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{{Short description|Main belt asteroid target of the Lucy mission}} | {{Short description|Main belt asteroid target of the Lucy mission}} | ||
{{Use dmy dates|date=January 2023}} |
{{Use dmy dates|date=January 2023}}<!-- DISCLAIMER: The page numbers listed in the {{rp|page=}} templates refer to the actual publication page number, not the PDF page number --> | ||
{{Infobox planet | {{Infobox planet | ||
| minorplanet = yes | | minorplanet = yes | ||
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| background = #D6D6D6 | | background = #D6D6D6 | ||
| image = Dinkinesh First Look L'LORRI.png | | image = Dinkinesh First Look L'LORRI.png | ||
| |
| image_scale = | ||
| caption = Dinkinesh and its satellite imaged by the '']'' spacecraft's L'LORRI camera | | caption = Dinkinesh and its satellite Selam imaged by the '']'' spacecraft's L'LORRI camera | ||
| discovery_ref = <ref name="jpldata" /> | | discovery_ref = <ref name="jpldata" /> | ||
| discoverer = ] | | discoverer = ] | ||
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| mpc_name = (152830) Dinkinesh | | mpc_name = (152830) Dinkinesh | ||
| alt_names = {{mp|1999 VD|57}}{{·}}{{mp|2004 HJ|78}}{{·}}{{mp|2007 CB|63}}<ref name="MPC-object"/> | | alt_names = {{mp|1999 VD|57}}{{·}}{{mp|2004 HJ|78}}{{·}}{{mp|2007 CB|63}}<ref name="MPC-object"/> | ||
| pronounced = | | pronounced = {{IPAc-en|'|d|I|N|k|ᵻ|n|E|S}} | ||
| named_after = | | named_after = ] (Lucy fossil) | ||
| mp_category = ]<ref name="jpldata" />{{·}}{{small|(])}} | | mp_category = ]<ref name="jpldata" />{{·}}{{small|(])}} | ||
| orbit_ref =  <ref name="jpldata" /> | | orbit_ref =  <ref name="jpldata" /> | ||
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| semimajor = 2.191 AU | | semimajor = 2.191 AU | ||
| eccentricity = 0.1120 | | eccentricity = 0.1120 | ||
| period = 3.24 yr (1,185 |
| period = 3.24 yr (1,185 days) | ||
| mean_anomaly = 25.239] | | mean_anomaly = 25.239] | ||
| mean_motion = {{Deg2DMS|0.3038538|sup=ms}} / day | | mean_motion = {{Deg2DMS|0.3038538|sup=ms}} / day | ||
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| mass = | | mass = | ||
| density = | | density = | ||
| rotation = {{val| |
| rotation = {{val|3.7387|0.0013|u=h}}<ref name="Levison2024"/> | ||
| pole_ecliptic_lon = | | pole_ecliptic_lon = | ||
| pole_ecliptic_lat = | | pole_ecliptic_lat = | ||
Line 44: | Line 44: | ||
| albedo = {{val|0.27|0.25|0.06}}<ref name="McFadden2023"/> | | albedo = {{val|0.27|0.25|0.06}}<ref name="McFadden2023"/> | ||
| spectral_type = ]<ref name="Bolin2023"/><ref name="deLeon2023"/><br/>] = {{val|0.455|0.025}}<ref name="Mottola2023-09"/> | | spectral_type = ]<ref name="Bolin2023"/><ref name="deLeon2023"/><br/>] = {{val|0.455|0.025}}<ref name="Mottola2023-09"/> | ||
| abs_magnitude = {{val|17.62|0.04}} (])<ref name="Bolin2023"/><ref name="Mottola2023-09"/>{{rp|page=L3}} | | abs_magnitude = {{nowrap|{{val|17.62|0.04}} (])<ref name="Bolin2023"/><ref name="Mottola2023-09"/>{{rp|page=L3}}}} | ||
}} | }} | ||
'''152830 Dinkinesh''' (] '''{{mp|1999 VD|57}}''') is a ] ] about {{convert|790|m|ft|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered by the ] (LINEAR) survey at ] on 4 November 1999. Dinkinesh was the first ] target of ]'s ], which approached {{cvt|425|km|mi}} from the asteroid on 1 November 2023.<ref name="NASA-20230911"/> During the flyby, the ''Lucy'' spacecraft discovered that Dinkinesh has a ] {{convert|220|m|ft}} in diameter. |
'''152830 Dinkinesh''' (] '''{{mp|1999 VD|57}}''') is a ] ] about {{convert|790|m|ft|abbr=off|sigfig=2|sp=us}} in diameter. It was discovered by the ] (LINEAR) survey at ] on 4 November 1999. Dinkinesh, the name borrowed from an Ethiopian word for the ], was the first ] target of ]'s ], which approached {{cvt|425|km|mi}} from the asteroid on 1 November 2023.<ref name="NASA-20230911"/> During the flyby, the ''Lucy'' spacecraft discovered that Dinkinesh has a ] ], named Selam, which is {{convert|220|m|ft|sp=us}} in diameter. Dinkinesh is the ], though some smaller ]s have also been explored. | ||
== Discovery and observational history == | == Discovery and observational history == | ||
Dinkinesh was discovered on 4 November 1999 by the ] (LINEAR) sky survey at ].<ref name="MPC-object"/> The discovery observations were published by the ] (MPC) on 23 November 1999 and the asteroid was given the ] ] {{mp|1999 VD|57}}, which describes its discovery year, month, and order.<ref name="MPS7496"/> The LINEAR and ] (], ]) surveys continued observing Dinkinesh until 15 November 1999, after which the asteroid became ] and went unrecognized for years.<ref name="MPC-object"/> | Dinkinesh was discovered on 4 November 1999 by the ] (LINEAR) sky survey at ].<ref name="MPC-object"/> The discovery observations were published by the ] (MPC) on 23 November 1999 and the asteroid was given the ] ] {{mp|1999 VD|57}}, which describes its discovery year, month, and discovery order within the month.<ref name="MPS7496"/> The LINEAR and ] (], ]) surveys continued observing Dinkinesh until 15 November 1999, after which the asteroid became ] and went unrecognized for years.<ref name="MPC-object"/> | ||
On 19 April 2004, Spacewatch reobserved Dinkinesh as a seemingly new asteroid, but misattributed these observations to those of another unrelated asteroid, {{mp|2004 GZ|43}}, which was discovered by the same survey on 12 April 2004.<ref name="MPC-object"/><ref name="MPS105236"/> Dinkinesh was again reobserved as a seemingly new asteroid on 15 and 17 February 2007 by ]'s ] (NEAT) survey at ], which led the MPC to give Dinkinesh the provisional designation {{mp|2007 CB|63}} on 25 February 2007.<ref name="MPC-object"/><ref name="MPS200485"/> ], the associate director of the MPC at time, recognized that {{mp|1999 VD|57}} and {{mp|2007 CB|63}} were the same asteroid and published the linkage on 2 March 2007.<ref name="MPEC-2007-E01"/><ref name="MPO116514"/> The linkage between Dinkinesh's 1999 and 2007 observations enabled the MPC to find additional observations from 2001–2007, where the asteroid was previously detected unknowingly.<ref name="MPS201406"/><ref name="MPO115681"/> The linkage and additional observations extended Dinkinesh's ] to over 7 years and greatly ] |
On 19 April 2004, Spacewatch reobserved Dinkinesh as a seemingly new asteroid, but misattributed these observations to those of another unrelated asteroid, {{mp|2004 GZ|43}}, which was discovered by the same survey on 12 April 2004.<ref name="MPC-object"/><ref name="MPS105236"/> Dinkinesh was again reobserved as a seemingly new asteroid on 15 and 17 February 2007 by ]'s ] (NEAT) survey at ], which led the MPC to give Dinkinesh the provisional designation {{mp|2007 CB|63}} on 25 February 2007.<ref name="MPC-object"/><ref name="MPS200485"/> ], the associate director of the MPC at the time, recognized that {{mp|1999 VD|57}} and {{mp|2007 CB|63}} were the same asteroid and published the linkage on 2 March 2007.<ref name="MPEC-2007-E01"/><ref name="MPO116514"/> The linkage between Dinkinesh's 1999 and 2007 observations enabled the MPC to find additional observations from 2001–2007, where the asteroid was previously detected unknowingly.<ref name="MPS201406"/><ref name="MPO115681"/> The linkage and additional observations extended Dinkinesh's ] to over 7 years and greatly ]. This allowed the MPC to give Dinkinesh its permanent ] 152830 on 2 April 2007.<ref name="MPC59323"/><ref name="MPO116514"/> ] LINEAR observations of Dinkinesh from 15 October 1999 were later identified and published on 19 August 2007, extending the observation arc by another 5 years.<ref name="MPS213622"/> | ||
On 3 March 2007, the MPC established that Spacewatch's 2004 observations of Dinkinesh were not of {{mp|2004 GZ|43}}, and thus redesignated these observations as {{mp|2004 HJ|78}}.<ref name="MPC58994"/> However, the MPC did not recognize that {{mp|2004 HJ|78}} was Dinkinesh until Gareth Williams made the linkage and published it on 9 February 2009.<ref name="MPC64979"/> | On 3 March 2007, the MPC established that Spacewatch's 2004 observations of Dinkinesh were not of {{mp|2004 GZ|43}}, and thus redesignated these observations as {{mp|2004 HJ|78}}.<ref name="MPC58994"/> However, the MPC did not recognize that {{mp|2004 HJ|78}} was Dinkinesh until Gareth Williams made the linkage and published it on 9 February 2009.<ref name="MPC64979"/> | ||
== Name == | == Name == | ||
'' |
''Dinkinesh'' is the ] name for the ], after which ]'s '']'' mission is named.<ref name="SN-20230125"/> The name means "you are wonderful" in the Amharic language ({{lang|am|ድንቅነሽ}}).<ref name="WGSBN-V3-2"/><ref name="SciTechDaily-20230301"/> "Din(i)k’i" means "wonderful"<ref>{{Cite web |url=https://www.indifferentlanguages.com/words/wonderful/amharic |title=How to Say Wonderful in Amharic |access-date=29 October 2023 |archive-date=29 October 2023 |archive-url=https://web.archive.org/web/20231029042836/https://www.indifferentlanguages.com/words/wonderful/amharic |url-status=live }}</ref> and "nesh" means "you are" in feminine form of this pronoun and verb.<ref>{{Cite web |url=https://static1.squarespace.com/static/58d6b5f4e3df283d54bf151e/t/5a7125e1e4966be6e6de299b/1517364706102/3+-+Helpful+Amharic+Words+%26+Phrases.pdf |title=Helpful Amharic Words & Phrases |access-date=29 October 2023 |archive-date=29 October 2023 |archive-url=https://web.archive.org/web/20231029045439/https://static1.squarespace.com/static/58d6b5f4e3df283d54bf151e/t/5a7125e1e4966be6e6de299b/1517364706102/3+-+Helpful+Amharic+Words+%26+Phrases.pdf |url-status=live }}</ref> The asteroid was unnamed when it was selected for exploration by the ''Lucy'' spacecraft, so the ''Lucy'' mission team proposed the name Dinkinesh to the ]'s ] (WGSBN), which approved and announced the name on 6 February 2023.<ref name="SN-20230125"/><ref name="WGSBN-V3-2"/> | ||
== Orbit == | == Orbit == | ||
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== Exploration == | == Exploration == | ||
The ''Lucy'' spacecraft made a ] of Dinkinesh from a distance of {{cvt|425|km|mi}} on 1 November 2023 16:54 ].<ref name="NASA-20231101"/> ''Lucy''{{'}}s flyby of Dinkinesh was announced by NASA and the ''Lucy'' science team on 25 January 2023, more than one year after ''Lucy'' had launched in October 2021.<ref name="NASA-20230125"/> The asteroid was initially overlooked as a potential flyby target because it was too small.<ref name="NASA-20230125"/> It was identified in August 2022 by Raphael Marschall, mission collaborator of the ], who investigated 500,000 asteroids for potential close approaches with the spacecraft.<ref name="NASA-20230125"/><ref name="Spencer2023b"/> The original trajectory of ''Lucy'' took it within {{cvt|64000|km|mi}} of Dinkinesh, but a series of planned ]s from May to September 2023 allowed ''Lucy'' to approach much closer.<ref name="NASA-20230125"/><ref name="NASA-20230518"/><ref name="NASA-20231013"/> | |||
] | |||
]'' spacecraft in September 2023]] | |||
The ''Lucy'' spacecraft made a ] of Dinkinesh from a distance of {{cvt|425|km|mi}} on 1 November 2023 16:54 ].<ref name="NASA-20231101"/> ''Lucy''{{'}}s flyby of Dinkinesh was announced by NASA and the ''Lucy'' science team on 25 January 2023, more than one year after ''Lucy'' had launched in October 2021.<ref name="NASA-20230125"/> The asteroid was initially overlooked as a potential flyby target because it was too small.<ref name="NASA-20230125"/> It was identified in August 2022 by Raphael Marschall, mission collaborator of the ], after he investigated 500,000 asteroids for potential close approaches with the spacecraft.<ref name="NASA-20230125"/><ref name="Spencer2023b"/> The original trajectory of ''Lucy'' took it within {{cvt|64000|km|mi}} of Dinkinesh, but a series of planned ]s from May to September 2023 allowed ''Lucy'' to approach much closer.<ref name="NASA-20230125"/><ref name="NASA-20230518"/><ref name="NASA-20231013"/> | |||
Dinkinesh was ''Lucy''{{'}}s first and smallest asteroid flyby during its mission, and is the ].<ref name="NASA-20230125"/> The Dinkinesh flyby served to test ''Lucy''{{'}}s autonomous tracking capabilities before it will apply them to its main science targets, the ].<ref name="NASA-20230125"/><ref name="Spencer2023a"/> ''Lucy'' took its first images of Dinkinesh on 3–5 September 2023, when the asteroid was {{convert|23|e6km|e6mi|abbr=unit}} away from the spacecraft.<ref name="NASA-20230911"/> The spacecraft continued imaging Dinkinesh from afar to aid its optical navigation over the |
Dinkinesh was ''Lucy''{{'}}s first and smallest asteroid flyby during its mission, and is the ].<ref name="NASA-20230125"/> The Dinkinesh flyby served to test ''Lucy''{{'}}s autonomous tracking capabilities before it will apply them to its main science targets, the ].<ref name="NASA-20230125"/><ref name="Spencer2023a"/> ''Lucy'' took its first images of Dinkinesh on 3–5 September 2023, when the asteroid was {{convert|23|e6km|e6mi|abbr=unit}} away from the spacecraft.<ref name="NASA-20230911"/> The spacecraft continued imaging Dinkinesh from afar to aid its optical navigation over the days before the flyby.<ref name="NASA-20230911"/> Because Dinkinesh is very small, ''Lucy'' did not resolve surface detail on Dinkinesh until the day of the flyby.<ref name="NASA-20230911"/> At closest approach, ''Lucy'' was moving {{cvt|4.5|km/s|mi/s}} relative to Dinkinesh and it was expected to take 2 meters/pixel resolution images of the asteroid with the panchromatic L'LORRI imager, 15 m/pixel color images with the L'Ralph imager, and 24 m/pixel ] spectra and thermal measurements with the L'TES ].<ref name="NASA-20230911"/><ref name="Spencer2023a"/> After the flyby, ''Lucy''{{'}}s L'LORRI instrument continued observing Dinkinesh for four days to measure the asteroid's ].<ref name="NASA-20231101"/> | ||
{{Multiple image | |||
| image1 = Asteroid (152830) 1999 VD57 Lucy flyby diagram.webp | |||
| image2 = Dinkinesh opnav blink crop Sep 2023.gif | |||
| total_width = 800 | |||
| alt1 = Orbit diagram of Lucy's flyby of Dinkinesh (1999 VD57) on 1 November 2023 | |||
| caption1 = Orbit diagram of Lucy's flyby of Dinkinesh (1999 VD57) on 1 November 2023 | |||
| alt2 = First images of Dinkinesh (circled) by the Lucy spacecraft in September 2023 | |||
| caption2 = First images of Dinkinesh (circled) by the Lucy spacecraft in September 2023 | |||
| caption_align = center | |||
| align = center | |||
}} | |||
== Satellite == | == Satellite == | ||
{{anchor|Selam}} | |||
] | |||
During the flyby, the ''Lucy'' spacecraft discovered that Dinkinesh has a ] {{convert|220|m|ft}} in diameter.<ref name="NASA-20231102"/> Together, Dinkinesh and its satellite form a ] ]. The Dinkinesh binary system resembles the ] binary system in size and composition but differ in location from the Sun, which allows scientists to compare the nature of binary asteroids in different environments.<ref name="SA-20231103"/> In the weeks prior to the flyby, the ''Lucy'' spacecraft found that Dinkinesh's brightness did not vary as predicted, which provided the first hints of Dinkinesh's binary nature.<ref name="NASA-20231102"/><ref name="JHUAPL-20231102"/> | |||
{{Infobox planet | |||
| image = File:Lucy_Sees_Asteroid_Dinkinesh_in_Detail_(SVS14596_-_selamstereo_redblue_preview).png | |||
| caption = | |||
| name = Selam | |||
| discoverer = Lucy | |||
| discovered = 27 November 2023 | |||
| mpc_name = | |||
| alt_names = Dinkinesh I<br />S/2023 (152830) 1 | |||
| pronounced = {{IPAc-en|s|@|'|l|A:|m}} | |||
| note = | |||
| orbit_ref = <ref name="johnston"/><ref name="Levison2024"/> | |||
| periapsis = | |||
| apoapsis = | |||
| semimajor = {{val|3.11|0.05|u=km}} | |||
| eccentricity = ≈0 | |||
| period = {{val|52.67|0.04|u=h}} | |||
| inclination = | |||
| satellite_of = Dinkinesh | |||
| physical_ref = <ref name="johnston"/><ref name="Levison2024"/> | |||
| mean_diameter = {{val|220|u=m}} | |||
| dimensions = {{val|240|x|200|x|200|u=m}} <small>(inner lobe)</small><br/>{{val|280|x|220|x|210|u=m}} <small>(outer lobe)</small> | |||
| mean_radius = | |||
| spectral_type = | |||
| magnitude = | |||
| abs_magnitude = | |||
| rotation = {{val|52.44|0.14|u=h}} <small>(likely ])</small> | |||
}} | |||
During the flyby, the ''Lucy'' spacecraft discovered that Dinkinesh has a ] {{cvt|220|m|ft}} in diameter.<ref name="NASA-20231102"/> The satellite is named ''']''' ({{IPAc-en|s|@|'|l|A:|m}}; full designation '''Dinkinesh I Selam'''), after the fossil remains of a three-year-old '']'' female hominin (the same species as the Lucy fossil) found in ], Ethiopia in 2000.<ref name="WGSBN-V3-16"/>{{rp|page=5}} Selam means "peace" in the Amharic language ({{lang|am|ሰላም}}) and it was proposed by Raphael Marschall.<ref name="NASA-20231129"/> The name was approved by the International Astronomical Union's WGSBN on 27 November 2023.<ref name="NASA-20231129"/><ref name="WGSBN-V3-16"/>{{rp|page=5}} | |||
Together, Dinkinesh and Selam form a ] ]. Dinkinesh is the second binary main-belt asteroid explored by spacecraft, after ] by '']'' in 1993. The Dinkinesh binary system resembles the ] ] binary system in size and composition, but differs in location from the Sun, which allows scientists to compare the nature of binary asteroids in different environments.<ref name="SA-20231103"/><ref name="Merrill2024"/> In the weeks prior to the flyby, the ''Lucy'' spacecraft found that Dinkinesh's brightness did not vary as predicted, which provided the first hints of Dinkinesh's binary nature.<ref name="NASA-20231102"/><ref name="JHUAPL-20231102"/> Images of Selam taken after ''Lucy''{{'}}s approach revealed that it is a ] with two lobes attached to each other. While contact binary asteroids are common in the Solar System, Selam is the first known example of a contact binary satellite of an asteroid.<ref name="NASA-20231107"/> | |||
{{Multiple image | |||
| direction = horizontal | |||
| total_width = 900 | |||
| image1 = Dinkinesh-family-portrait-2.png | |||
| image2 = Ttcam1-deconv-2023305-dinkinesh-ql-cropped-north.gif | |||
| image3 = MVIC Selam.jpg | |||
| alt3 = Dinkinesh and Selam imaged in false color by Lucy's L'Ralph imager | |||
| caption3 = Dinkinesh and Selam imaged in ] by Lucy's L'Ralph imager | |||
| alt2 = Dinkinesh and Selam imaged by Lucy's terminal tracking camera during approach. Selam's apparent motion is primarily due to the changing perspective during Lucy's approach. | |||
| caption2 = Dinkinesh and Selam imaged by Lucy's terminal tracking camera during approach. Selam's apparent motion is primarily due to the changing perspective during Lucy's approach. | |||
| alt1 = Dinkinesh and Selam imaged six minutes after closest approach, revealing the satellite's contact binary shape | |||
| caption1 = Dinkinesh and Selam imaged six minutes after closest approach, revealing the satellite's contact binary shape | |||
| align = center | |||
}} | |||
=== Origin === | |||
Selam is expected to have a similar origin as the satellites of ] asteroids, which are thought to have originated from mass shedding events from the primary body in the past.<ref name="S&T-20231103"/><ref name="Merrill2024"/> These mass shedding events occur when the asteroid rotates fast enough that material accumulates along the equator and becomes ejected into orbit by the ].<ref name="S&T-20231103"/><ref name="Hyodo2022"/> The ejected material forms a disk around the asteroid, which eventually coalesces into a satellite.<ref name="S&T-20231103"/> The uneven reflection of sunlight off an asteroid's surface, which is called the ], is responsible for rotationally accelerating asteroids to the point of mass shedding.<ref name="S&T-20231103"/> During a mass shedding event, the asteroid's ] is transferred to its ejected material, which slows down the asteroid's rotation rate as a result.<ref name="S&T-20231103"/> | |||
One possible explanation for the origin of Selam's contact binary nature is rotational fissioning by the YORP effect.<ref name="Jacobson2011"/><ref name="UT-20231109"/> In this scenario, the fissioned satellite is split into two separate satellites in orbit around Dinkinesh, making it a triple asteroid system. This triple asteroid system is unstable due to chaotic ] between the satellites, and eventually leads to one of the satellites colliding with either the primary asteroid or the other satellite.<ref name="Jacobson2011"/>{{rp|page=170}} If the collision between two satellites occurs at slow enough speeds (less than {{cvt|50|mm/s|in/s|disp=or}}), the impact does not disrupt the shapes of the two bodies and instead forms a contact binary.<ref name="Jacobson2011"/>{{rp|page=167}} | |||
Dinkinesh's satellite is expected to have a similar origin as the satellites of ] asteroids, which are thought to have originated from mass shedding events from the primary body in the past. These mass shedding events occur when the asteroid rotates fast enough that material accumulates along the equator and becomes ejected into orbit.<ref name="S&T-20231103"/> The ejected material forms a disk around the asteroid, which eventually coalesces into a satellite.<ref name="S&T-20231103"/> The uneven reflection of sunlight off an asteroid's surface, which is called the ], is responsible for rotationally accelerating asteroids to the point of mass shedding.<ref name="S&T-20231103"/> During a mass shedding event, the asteroid's ] is transferred to its ejected material, which slows down the asteroid's rotation rate as a result.<ref name="S&T-20231103"/> | |||
== Physical characteristics == | == Physical characteristics == | ||
=== Geology === | === Geology === | ||
] | |||
The surfaces of Dinkinesh and its satellite are covered with boulders and ]s.<ref name="S&T-20231103"/> The outline of Dinkinesh's shape is not smooth, which suggests that the asteroid is relatively old.<ref name="SA-20231103"/> Dinkinesh bears an ], which suggests that the asteroid has experienced mass shedding in the past.<ref name="S&T-20231103"/> Dinkinesh's equatorial ridge also has a secondary ridge that branches off it.<ref name="SA-20231103"/> Dinkinesh's shape resembles the near-Earth asteroid ] and ], which are known to have ] interior structures consisting of rocks and dust loosely held by gravity. Because of this similarity, Dinkinesh is thought to likely have a rubble pile structure as well.<ref name="S&T-20231103"/> | |||
The surfaces of Dinkinesh and Selam are covered with boulders and ]s.<ref name="S&T-20231103"/> The outline of Dinkinesh's shape is not smooth, which suggests that the asteroid is relatively old.<ref name="SA-20231103"/> Dinkinesh bears an ], which suggests that the asteroid has experienced mass shedding in the past.<ref name="S&T-20231103"/> Dinkinesh's equatorial ridge also has a secondary ] that branches off it.<ref name="SA-20231103"/> Dinkinesh's shape resembles the near-Earth asteroids ] and ], which are known to have ] interior structures consisting of rocks and dust loosely held by gravity. Because of this similarity, Dinkinesh is thought to likely have a rubble pile structure as well.<ref name="S&T-20231103"/> | |||
A ridge is also present on |
A ridge is also present on Selam, but it is not oriented along its equator.<ref name="SA-20231103"/> The reason for Selam's unaligned ridge remains yet to be determined.<ref name="SA-20231103"/> | ||
=== Surface composition === | === Surface composition === | ||
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=== Rotation and light curve === | === Rotation and light curve === | ||
Dinkinesh ] every {{val|3.7387|0.0013|u=h}}. As Dinkinesh rotates, its brightness from Earth fluctuates due to its non-spherical shape, which can be inferred from the ] of the asteroid's rotational ].<ref name="Mottola2023-06"/><ref name="Mottola2023-09"/> The first ] observations of Dinkinesh's rotational light curve were attempted with the ]'s 0.8-m IAC-80 telescope at ], Spain in November 2022, but it did not observe Dinkinesh long enough to make conclusive findings.<ref name="deLeon2023"/>{{rp|page=4}} Longer photometric observations of Dinkinesh were made with the ]'s 1.23-m telescope at ], Spain from November 2022–February 2023, which discovered that Dinkinesh rotates slowly and had a light curve amplitude of {{val|0.39|0.02}} ].<ref name="Mottola2023-06"/><ref name="Mottola2023-09"/>{{rp|page=1}} | |||
{{update section|date=November 2023|reason=The discovery of Dinkinesh's satellite may change information about Dinkinesh's rotation. Additional updates will be made as later announcements release new information}} | |||
Dinkinesh rotates slowly with a ] of {{val|52.67|0.04|u=h}}. As Dinkinesh rotates, its brightness from Earth fluctuates due to its non-spherical shape, which can be inferred from the ] of the asteroid's rotational ].<ref name="Mottola2023-06"/><ref name="Mottola2023-09"/> The first ] observations of Dinkinesh's rotational light curve were attempted with the ]'s 0.8-m IAC-80 telescope at ], Spain in November 2022, but it did not observe Dinkinesh long enough to make conclusive findings.<ref name="deLeon2023"/>{{rp|page=4}} Longer photometric observations of Dinkinesh were made with the ]'s 1.23-m telescope at ], Spain from November 2022–February 2023, which discovered that Dinkinesh rotates slowly and had a light curve amplitude of {{val|0.39|0.02}} ].<ref name="Mottola2023-06"/><ref name="Mottola2023-09"/>{{rp|page=1}} | |||
=== Diameter and albedo === | === Diameter and albedo === | ||
''Lucy'' images of Dinkinesh show that it measures {{cvt|790|m|ft}} across its |
''Lucy'' images of Dinkinesh show that it measures approximately {{cvt|790|m|ft}} across its equator.<ref name="NASA-20231102"/><ref name="S&T-20231103"/> This is in agreement with the previous diameter estimates from measured ] and average S-type asteroid albedo.<ref name="Bolin2023" /><ref name="deLeon2023" /><ref name="Mottola2023-09" /> Reprocessing of archival ] ] observations by the ] (WISE) from March 2010 give a consistent result.<ref name="McFadden2023"/><ref name="S&T-20231103"/> | ||
{{clear|left}} | {{clear|left}} | ||
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<ref name="jpldata">{{cite web | <ref name="jpldata">{{cite web | ||
|type = 2022-11-05 last obs. | |type = 2022-11-05 last obs. | ||
|title = JPL Small-Body Database Browser: 152830 (1999 VD57) | |title = JPL Small-Body Database Browser: 152830 Dinkinesh (1999 VD57) | ||
|url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2152830 | |url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2152830 | ||
|publisher = ] | |publisher = ] | ||
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<ref name="MPC-object">{{cite web | <ref name="MPC-object">{{cite web | ||
|title = (152830) = 2004 HJ78 = 1999 VD57 = 2007 CB63 | |title = (152830) Dinkinesh = 2004 HJ78 = 1999 VD57 = 2007 CB63 | ||
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=152830 | |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=152830 | ||
|publisher = Minor Planet Center | |publisher = Minor Planet Center | ||
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|archive-url = https://web.archive.org/web/20230913073229/https://www.minorplanetcenter.net/iau/ECS/MPCArchive/1999/MPS_19991123.pdf | |archive-url = https://web.archive.org/web/20230913073229/https://www.minorplanetcenter.net/iau/ECS/MPCArchive/1999/MPS_19991123.pdf | ||
|archive-date = 13 September 2023}}</ref> | |archive-date = 13 September 2023}}</ref> | ||
<ref name="johnston">{{cite web | |||
|title = (152830) Dinkinesh and Selam | |||
|url = https://johnstonsarchive.net/astro/astmoons/am-152830.html | |||
|work = Johnston's Archive | |||
|publisher = Wm. Robert Johnston | |||
|accessdate = 27 March 2024}}</ref> | |||
<ref name="MPS105236">{{cite web | <ref name="MPS105236">{{cite web | ||
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|publisher = Minor Planet Center | |publisher = Minor Planet Center | ||
|date = 2 March 2007 | |date = 2 March 2007 | ||
|accessdate = 13 September 2023 |
|accessdate = 13 September 2023 | ||
|archive-date = 8 November 2023 | |||
|archive-url = https://web.archive.org/web/20231108114513/https://minorplanetcenter.net/mpec/K07/K07E01.html | |||
|url-status = live}}</ref> | |||
<ref name="MPC58994">{{cite web | <ref name="MPC58994">{{cite web | ||
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|archive-url = https://web.archive.org/web/20170828093841/http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2009/MPC_20090209.pdf | |archive-url = https://web.archive.org/web/20170828093841/http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2009/MPC_20090209.pdf | ||
|archive-date = 28 August 2017}}</ref> | |archive-date = 28 August 2017}}</ref> | ||
<ref name="Jacobson2011">{{cite journal | |||
|first1 = Seth A. |last1 = Jacobson | |||
|first2 = Daniel J. |last2 = Scheeres | |||
|title = Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems | |||
|journal = Icarus | |||
|date = July 2011 | |||
|volume = 214 | |||
|issue = 1 | |||
|pages = 161–178 | |||
|doi = 10.1016/j.icarus.2011.04.009 | |||
|arxiv = 1404.0801 | |||
|bibcode = 2011Icar..214..161J | |||
|s2cid = 119245876}}</ref> | |||
<ref name="Merrill2024">{{cite journal | |||
|last1=Merrill |first1=Colby | |||
|last2=Kubas |first2=Alexia | |||
|last3=Meyer |first3=Alex | |||
|last4=Raducan |first4=Sabina | |||
|title=Age of (152830) Dinkinesh I Selam constrained by secular tidal-BYORP theory | |||
|journal=Astronomy and Astrophysics | |||
|date=2024 | |||
|volume=684 | |||
|page=L20 | |||
|doi=10.1051/0004-6361/202449716 | |||
|bibcode=2024A&A...684L..20M | |||
|url=https://doi.org/10.1051/0004-6361/202449716}}</ref> | |||
<ref name="Hyodo2022">{{cite journal | |||
|first1 = Ryuki |last1 = Hyodo | |||
|first2 = Keisuke |last2 = Sugiura | |||
|title = Formation of Moons and Equatorial Ridge around Top-shaped Asteroids after Surface Landslide | |||
|journal = The Astrophysical Journal Letters | |||
|date = October 2022 | |||
|volume = 937 | |||
|issue = 2 | |||
|id = L36 | |||
|pages = 6 | |||
|doi-access = free | |||
|doi = 10.3847/2041-8213/ac922d | |||
|arxiv = 2209.07045 | |||
|bibcode = 2022ApJ...937L..36H | |||
|s2cid = 252280407}}</ref> | |||
<ref name="NASA-20230125">{{cite web | <ref name="NASA-20230125">{{cite web | ||
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|title = NASA adds asteroid flyby to Lucy mission | |title = NASA adds asteroid flyby to Lucy mission | ||
|url = https://spacenews.com/nasa-adds-asteroid-flyby-to-lucy-mission/ | |url = https://spacenews.com/nasa-adds-asteroid-flyby-to-lucy-mission/ | ||
|first = Jeff |last = Foust |
|first = Jeff | ||
|last = Foust | |||
|work = SpaceNews | |work = SpaceNews | ||
|date = 26 January 2023 | |date = 26 January 2023 | ||
|accessdate = 26 January 2023 |
|accessdate = 26 January 2023 | ||
|archive-date = 8 November 2023 | |||
|archive-url = https://web.archive.org/web/20231108114515/https://spacenews.com/nasa-adds-asteroid-flyby-to-lucy-mission/ | |||
|url-status = live}}</ref> | |||
<ref name="WGSBN-V3-2">{{cite journal | <ref name="WGSBN-V3-2">{{cite journal | ||
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|doi-access = free | |doi-access = free | ||
|doi = 10.3847/PSJ/acc848 | |doi = 10.3847/PSJ/acc848 | ||
|bibcode = 2023PSJ.....4...72P |
|bibcode = 2023PSJ.....4...72P|hdl= 10138/358328 | ||
|hdl-access= free | |||
}}</ref> | |||
<ref name="Spencer2023a">{{cite conference | <ref name="Spencer2023a">{{cite conference | ||
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|pages = L1–L4 | |pages = L1–L4 | ||
|doi = 10.1093/mnrasl/slad066 | |doi = 10.1093/mnrasl/slad066 | ||
| |
|doi-access = free | ||
|arxiv = | |||
|bibcode = 2023MNRAS.524L...1M}}</ref> | |bibcode = 2023MNRAS.524L...1M}}</ref> | ||
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|volume = 55 | |volume = 55 | ||
|id = 102.06 | |id = 102.06 | ||
| |
|bibcode = | ||
| |
|access-date = 2 October 2023 | ||
|archive-date = 8 November 2023 | |||
|archive-url = https://web.archive.org/web/20231108115021/https://submissions.mirasmart.com/DPS55/Itinerary/EventsAAG.aspx | |||
|url-status = live}}</ref> | |||
<ref name="NASA-20230518">{{cite web | <ref name="NASA-20230518">{{cite web | ||
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<ref name="NASA-20231101">{{cite web | <ref name="NASA-20231101">{{cite web | ||
|title = NASAs Lucy Spacecraft Hours Away from 1st Asteroid Encounter | |||
|url = https://blogs.nasa.gov/lucy/2023/11/01/nasas-lucy-spacecraft-hours-away-from-1st-asteroid-encounter/ | |||
|first = Erin |last = Morton | |||
|work = NASA Blogs | |||
|publisher = NASA | |||
|date = 1 November 2023 | |||
|accessdate = 1 November 2023 | |||
|archive-date = 2 November 2023 | |||
|archive-url = https://web.archive.org/web/20231102001611/https://blogs.nasa.gov/lucy/2023/11/01/nasas-lucy-spacecraft-hours-away-from-1st-asteroid-encounter/ | |||
|url-status = live}}</ref> | |||
<ref name="NASA-20231102">{{cite web | <ref name="NASA-20231102">{{cite web | ||
|title = NASA's Lucy Spacecraft Discovers 2nd Asteroid During Dinkinesh Flyby | |title = NASA's Lucy Spacecraft Discovers 2nd Asteroid During Dinkinesh Flyby | ||
|url = https://www.nasa.gov/image-article/nasas-lucy-spacecraft-discovers-2nd-asteroid-during-dinkinesh-flyby/ | |url = https://www.nasa.gov/image-article/nasas-lucy-spacecraft-discovers-2nd-asteroid-during-dinkinesh-flyby/ | ||
|first = Katherine |last = Kretke | |first = Katherine |last = Kretke | ||
|publisher = NASA | |publisher = NASA | ||
|date = 2 November 2023 | |date = 2 November 2023 | ||
|accessdate = 2 November 2023 |
|accessdate = 2 November 2023 | ||
|archive-date = 3 November 2023 | |||
|archive-url = https://web.archive.org/web/20231103065932/https://www.nasa.gov/image-article/nasas-lucy-spacecraft-discovers-2nd-asteroid-during-dinkinesh-flyby/ | |||
|url-status = live}}</ref> | |||
<ref name="JHUAPL-20231102">{{cite web | <ref name="JHUAPL-20231102">{{cite web | ||
|title = NASA's Lucy Mission Gets an Unexpected Twofer in First Asteroid Encounter | |title = NASA's Lucy Mission Gets an Unexpected Twofer in First Asteroid Encounter | ||
|url = https://www.jhuapl.edu/news/news-releases/231102-nasa-lucy-lorri-captures-unexpected-twofer-in-first-asteroid-encounter-dinkinesh | |url = https://www.jhuapl.edu/news/news-releases/231102-nasa-lucy-lorri-captures-unexpected-twofer-in-first-asteroid-encounter-dinkinesh | ||
|publisher = Johns Hopkins University Applied Physics Laboratory | |publisher = Johns Hopkins University Applied Physics Laboratory | ||
|date = 2 November 2023 | |date = 2 November 2023 | ||
|accessdate = 2 November 2023 |
|accessdate = 2 November 2023 | ||
|archive-date = 3 November 2023 | |||
|archive-url = https://web.archive.org/web/20231103021239/https://www.jhuapl.edu/news/news-releases/231102-nasa-lucy-lorri-captures-unexpected-twofer-in-first-asteroid-encounter-dinkinesh | |||
|url-status = live}}</ref> | |||
<ref name="S&T-20231103">{{cite news | <ref name="S&T-20231103">{{cite news | ||
|title = Lucy Mission Flies By Asteroid Dinkinesh, Finds a Little Surprise | |title = Lucy Mission Flies By Asteroid Dinkinesh, Finds a Little Surprise | ||
|url = https://skyandtelescope.org/astronomy-news/lucy-mission-flies-by-asteroid-dinkinesh-finds-a-little-surprise/ | |url = https://skyandtelescope.org/astronomy-news/lucy-mission-flies-by-asteroid-dinkinesh-finds-a-little-surprise/ | ||
|first = Emily |last = Lakdawalla | |first = Emily |last = Lakdawalla | ||
|work = Sky & Telescope | |work = Sky & Telescope | ||
|date = 3 November 2023 | |date = 3 November 2023 | ||
|accessdate = 3 November 2023 |
|accessdate = 3 November 2023 | ||
|archive-date = 3 November 2023 | |||
|archive-url = https://web.archive.org/web/20231103211054/https://skyandtelescope.org/astronomy-news/lucy-mission-flies-by-asteroid-dinkinesh-finds-a-little-surprise/ | |||
|url-status = live}}</ref> | |||
<ref name="SA-20231103">{{cite news | <ref name="SA-20231103">{{cite news | ||
|title = NASA Asteroid Mission Discovers Tiny Surprise Moon with 'Really Bizarre' Shape | |title = NASA Asteroid Mission Discovers Tiny Surprise Moon with 'Really Bizarre' Shape | ||
|url = https://www.scientificamerican.com/article/nasa-asteroid-mission-discovers-tiny-surprise-moon-with-really-bizarre-shape/ | |url = https://www.scientificamerican.com/article/nasa-asteroid-mission-discovers-tiny-surprise-moon-with-really-bizarre-shape/ | ||
|first = Meghan |last = Bartels | |first = Meghan |last = Bartels | ||
|work = Scientific American | |work = Scientific American | ||
|date = 3 November 2023 | |date = 3 November 2023 | ||
|accessdate = 3 November 2023 |
|accessdate = 3 November 2023 | ||
|archive-date = 3 November 2023 | |||
|archive-url = https://web.archive.org/web/20231103160810/https://www.scientificamerican.com/article/nasa-asteroid-mission-discovers-tiny-surprise-moon-with-really-bizarre-shape/ | |||
|url-status = live}}</ref> | |||
<ref name="NASA-20231107">{{cite web | |||
|title = NASA's Lucy Surprises Again, Observes 1st-ever Contact Binary Orbiting Asteroid | |||
|url = https://science.nasa.gov/missions/lucy/nasas-lucy-surprises-again-observes-1st-ever-contact-binary-orbiting-asteroid/ | |||
|first = Katherine |last = Kretke | |||
|publisher = NASA | |||
|date = 7 November 2023 | |||
|accessdate = 7 November 2023 | |||
|archive-date = 7 November 2023 | |||
|archive-url = https://web.archive.org/web/20231107193335/https://science.nasa.gov/missions/lucy/nasas-lucy-surprises-again-observes-1st-ever-contact-binary-orbiting-asteroid/ | |||
|url-status = live}}</ref> | |||
<ref name="UT-20231109">{{cite web | |||
|title = What? Wow! That New Asteroid Image from Lucy Just Got Even More Interesting | |||
|url = https://www.universetoday.com/164152/what-wow-that-new-asteroid-image-from-lucy-just-got-even-more-interesting/ | |||
|first = Collins |last = Petersen | |||
|work = Universe Today | |||
|date = 9 November 2023 | |||
|accessdate = 9 November 2023 | |||
|archive-date = 10 November 2023 | |||
|archive-url = https://web.archive.org/web/20231110053455/https://www.universetoday.com/164152/what-wow-that-new-asteroid-image-from-lucy-just-got-even-more-interesting/ | |||
|url-status = live}}</ref> | |||
<ref name="WGSBN-V3-16">{{cite journal | |||
|title = ''WGSBN Bulletin'' 3, #16 | |||
|url = https://www.wgsbn-iau.org/files/Bulletins/V003/WGSBNBull_V003_016.pdf | |||
|journal = WGSBN Bulletin | |||
|publisher = International Astronomical Union | |||
|volume = 3 | |||
|issue = 16 | |||
|pages = 12 | |||
|date = 27 November 2023 | |||
|accessdate = 27 November 2023 | |||
|archive-date = 28 November 2023 | |||
|archive-url = https://web.archive.org/web/20231128012438/https://www.wgsbn-iau.org/files/Bulletins/V003/WGSBNBull_V003_016.pdf | |||
|url-status = live}}</ref> | |||
<ref name="NASA-20231129">{{cite web | |||
|title = Satellite Discovered by NASA's Lucy Mission Gets Name | |||
|url = https://blogs.nasa.gov/lucy/2023/11/29/satellite-discovered-by-nasas-lucy-mission-gets-name/ | |||
|first = Erin |last = Morton | |||
|work = NASA Blogs | |||
|publisher = NASA | |||
|date = 29 November 2023 | |||
|accessdate = 29 November 2023 | |||
|archive-date = 30 November 2023 | |||
|archive-url = https://web.archive.org/web/20231130013309/https://blogs.nasa.gov/lucy/2023/11/29/satellite-discovered-by-nasas-lucy-mission-gets-name/ | |||
|url-status = live}}</ref> | |||
<ref name="Levison2024">{{cite journal |last1=Levison |first1=Harold F. |last2=Marchi |first2=Simone |last3=Noll |first3=Keith S. |display-authors=et al. |title=A contact binary satellite of the asteroid (152830) Dinkinesh |date=29 May 2024 |journal=Nature |volume=629 |issue=8014 |pages=1015–1020 |doi=10.1038/s41586-024-07378-0 |doi-access=free |pmid=38811709 |pmc=11136651 |arxiv=2406.19337 |bibcode=2024Natur.629.1015L }}</ref> | |||
}} | }} | ||
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{{Minor planets navigator| |number=152830| }} | {{Minor planets navigator| |number=152830| }} | ||
{{Solar System moons (compact)}} | |||
{{Small Solar System bodies}} | {{Small Solar System bodies}} | ||
{{2023 in space}} | {{2023 in space}} | ||
{{Portal bar|Astronomy|Stars|Spaceflight|Solar System}} | {{Portal bar|Astronomy|Stars|Spaceflight|Solar System}} | ||
{{Authority control}} | |||
{{DEFAULTSORT:152830}} | {{DEFAULTSORT:152830}} |
Latest revision as of 15:51, 4 January 2025
Main belt asteroid target of the Lucy mission
Dinkinesh and its satellite Selam imaged by the Lucy spacecraft's L'LORRI camera | |
Discovery | |
---|---|
Discovered by | LINEAR |
Discovery site | Lincoln Lab ETS |
Discovery date | 4 November 1999 |
Designations | |
MPC designation | (152830) Dinkinesh |
Pronunciation | /ˈdɪŋkɪnɛʃ/ |
Named after | Dinkʼinesh (Lucy fossil) |
Alternative designations | 1999 VD57 · 2004 HJ78 · 2007 CB63 |
Minor planet category | main-belt · (inner) |
Orbital characteristics | |
Epoch 25 February 2023 (JD 2460000.5) | |
Uncertainty parameter 0 | |
Observation arc | 23.06 yr (8,422 days) |
Earliest precovery date | 15 October 1999 |
Aphelion | 2.437 AU |
Perihelion | 1.946 AU |
Semi-major axis | 2.191 AU |
Eccentricity | 0.1120 |
Orbital period (sidereal) | 3.24 yr (1,185 days) |
Mean anomaly | 25.239° |
Mean motion | 0° 18 13.874 / day |
Inclination | 2.094° |
Longitude of ascending node | 21.380° |
Argument of perihelion | 66.711° |
Known satellites | 1 |
Physical characteristics | |
Mean diameter | 790 m (primary) |
Synodic rotation period | 3.7387±0.0013 h |
Geometric albedo | 0.27+0.25 −0.06 |
Spectral type | Sq V–R = 0.455±0.025 |
Absolute magnitude (H) | 17.62±0.04 (V-band) |
152830 Dinkinesh (provisional designation 1999 VD57) is a binary main-belt asteroid about 790 meters (2,600 feet) in diameter. It was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey at Socorro, New Mexico on 4 November 1999. Dinkinesh, the name borrowed from an Ethiopian word for the Lucy fossil, was the first flyby target of NASA's Lucy mission, which approached 425 km (264 mi) from the asteroid on 1 November 2023. During the flyby, the Lucy spacecraft discovered that Dinkinesh has a contact-binary natural satellite, named Selam, which is 220 meters (720 ft) in diameter. Dinkinesh is the smallest main-belt asteroid explored by spacecraft yet, though some smaller near-Earth asteroids have also been explored.
Discovery and observational history
Dinkinesh was discovered on 4 November 1999 by the Lincoln Near-Earth Asteroid Research (LINEAR) sky survey at Socorro, New Mexico. The discovery observations were published by the Minor Planet Center (MPC) on 23 November 1999 and the asteroid was given the minor planet provisional designation 1999 VD57, which describes its discovery year, month, and discovery order within the month. The LINEAR and Spacewatch (Kitt Peak, Arizona) surveys continued observing Dinkinesh until 15 November 1999, after which the asteroid became lost and went unrecognized for years.
On 19 April 2004, Spacewatch reobserved Dinkinesh as a seemingly new asteroid, but misattributed these observations to those of another unrelated asteroid, 2004 GZ43, which was discovered by the same survey on 12 April 2004. Dinkinesh was again reobserved as a seemingly new asteroid on 15 and 17 February 2007 by Palomar Observatory's Near-Earth Asteroid Tracking (NEAT) survey at San Diego County, California, which led the MPC to give Dinkinesh the provisional designation 2007 CB63 on 25 February 2007. Gareth V. Williams, the associate director of the MPC at the time, recognized that 1999 VD57 and 2007 CB63 were the same asteroid and published the linkage on 2 March 2007. The linkage between Dinkinesh's 1999 and 2007 observations enabled the MPC to find additional observations from 2001–2007, where the asteroid was previously detected unknowingly. The linkage and additional observations extended Dinkinesh's observation arc to over 7 years and greatly reduced uncertainties in its orbit. This allowed the MPC to give Dinkinesh its permanent minor planet catalog number 152830 on 2 April 2007. Pre-discovery LINEAR observations of Dinkinesh from 15 October 1999 were later identified and published on 19 August 2007, extending the observation arc by another 5 years.
On 3 March 2007, the MPC established that Spacewatch's 2004 observations of Dinkinesh were not of 2004 GZ43, and thus redesignated these observations as 2004 HJ78. However, the MPC did not recognize that 2004 HJ78 was Dinkinesh until Gareth Williams made the linkage and published it on 9 February 2009.
Name
Dinkinesh is the Amharic name for the Lucy fossil, after which NASA's Lucy mission is named. The name means "you are wonderful" in the Amharic language (ድንቅነሽ). "Din(i)k’i" means "wonderful" and "nesh" means "you are" in feminine form of this pronoun and verb. The asteroid was unnamed when it was selected for exploration by the Lucy spacecraft, so the Lucy mission team proposed the name Dinkinesh to the International Astronomical Union's Working Group for Small Bodies Nomenclature (WGSBN), which approved and announced the name on 6 February 2023.
Orbit
Dinkinesh orbits the Sun in the inner main asteroid belt on an elliptical orbit with an average distance of 2.19 astronomical units (328 million km, 204 million mi) and an orbital period of 3.24 years. With an orbital eccentricity of 0.112, Dinkinesh comes as close as 1.95 AU (292 million km; 181 million mi) from the Sun at perihelion to as far as 2.44 AU (365 million km; 227 million mi) at aphelion. The asteroid's orbit is inclined 2.1° with respect to the plane of the Solar System. Dinkinesh is possibly a member of the Flora family, a group of asteroids that share similar orbital characteristics as the family's parent asteroid 8 Flora.
Exploration
The Lucy spacecraft made a flyby of Dinkinesh from a distance of 425 km (264 mi) on 1 November 2023 16:54 UTC. Lucy's flyby of Dinkinesh was announced by NASA and the Lucy science team on 25 January 2023, more than one year after Lucy had launched in October 2021. The asteroid was initially overlooked as a potential flyby target because it was too small. It was identified in August 2022 by Raphael Marschall, mission collaborator of the Nice Observatory, who investigated 500,000 asteroids for potential close approaches with the spacecraft. The original trajectory of Lucy took it within 64,000 km (40,000 mi) of Dinkinesh, but a series of planned trajectory correction maneuvers from May to September 2023 allowed Lucy to approach much closer.
Dinkinesh was Lucy's first and smallest asteroid flyby during its mission, and is the smallest main-belt asteroid explored by spacecraft yet. The Dinkinesh flyby served to test Lucy's autonomous tracking capabilities before it will apply them to its main science targets, the Jupiter trojans. Lucy took its first images of Dinkinesh on 3–5 September 2023, when the asteroid was 23 million km (14 million mi) away from the spacecraft. The spacecraft continued imaging Dinkinesh from afar to aid its optical navigation over the days before the flyby. Because Dinkinesh is very small, Lucy did not resolve surface detail on Dinkinesh until the day of the flyby. At closest approach, Lucy was moving 4.5 km/s (2.8 mi/s) relative to Dinkinesh and it was expected to take 2 meters/pixel resolution images of the asteroid with the panchromatic L'LORRI imager, 15 m/pixel color images with the L'Ralph imager, and 24 m/pixel near-infrared spectra and thermal measurements with the L'TES spectrometer. After the flyby, Lucy's L'LORRI instrument continued observing Dinkinesh for four days to measure the asteroid's light curve.
Orbit diagram of Lucy's flyby of Dinkinesh (1999 VD57) on 1 November 2023First images of Dinkinesh (circled) by the Lucy spacecraft in September 2023Satellite
Discovery | |
---|---|
Discovered by | Lucy |
Discovery date | 27 November 2023 |
Designations | |
Pronunciation | /səˈlɑːm/ |
Alternative names | Dinkinesh I S/2023 (152830) 1 |
Orbital characteristics | |
Semi-major axis | 3.11±0.05 km |
Eccentricity | ≈0 |
Orbital period (sidereal) | 52.67±0.04 h |
Satellite of | Dinkinesh |
Physical characteristics | |
Dimensions | 240 m × 200 m × 200 m (inner lobe) 280 m × 220 m × 210 m (outer lobe) |
Mean diameter | 220 m |
Synodic rotation period | 52.44±0.14 h (likely synchronous) |
During the flyby, the Lucy spacecraft discovered that Dinkinesh has a natural satellite 220 m (720 ft) in diameter. The satellite is named Selam (/səˈlɑːm/; full designation Dinkinesh I Selam), after the fossil remains of a three-year-old Australopithecus afarensis female hominin (the same species as the Lucy fossil) found in Dikika, Ethiopia in 2000. Selam means "peace" in the Amharic language (ሰላም) and it was proposed by Raphael Marschall. The name was approved by the International Astronomical Union's WGSBN on 27 November 2023.
Together, Dinkinesh and Selam form a binary asteroid system. Dinkinesh is the second binary main-belt asteroid explored by spacecraft, after 243 Ida by Galileo in 1993. The Dinkinesh binary system resembles the 65803 Didymos near-Earth asteroid binary system in size and composition, but differs in location from the Sun, which allows scientists to compare the nature of binary asteroids in different environments. In the weeks prior to the flyby, the Lucy spacecraft found that Dinkinesh's brightness did not vary as predicted, which provided the first hints of Dinkinesh's binary nature. Images of Selam taken after Lucy's approach revealed that it is a contact binary with two lobes attached to each other. While contact binary asteroids are common in the Solar System, Selam is the first known example of a contact binary satellite of an asteroid.
Dinkinesh and Selam imaged six minutes after closest approach, revealing the satellite's contact binary shapeDinkinesh and Selam imaged by Lucy's terminal tracking camera during approach. Selam's apparent motion is primarily due to the changing perspective during Lucy's approach.Dinkinesh and Selam imaged in false color by Lucy's L'Ralph imagerOrigin
Selam is expected to have a similar origin as the satellites of rubble pile asteroids, which are thought to have originated from mass shedding events from the primary body in the past. These mass shedding events occur when the asteroid rotates fast enough that material accumulates along the equator and becomes ejected into orbit by the centrifugal force. The ejected material forms a disk around the asteroid, which eventually coalesces into a satellite. The uneven reflection of sunlight off an asteroid's surface, which is called the Yarkovsky–O'Keefe–Radzievskii–Paddack (YORP) effect, is responsible for rotationally accelerating asteroids to the point of mass shedding. During a mass shedding event, the asteroid's angular momentum is transferred to its ejected material, which slows down the asteroid's rotation rate as a result.
One possible explanation for the origin of Selam's contact binary nature is rotational fissioning by the YORP effect. In this scenario, the fissioned satellite is split into two separate satellites in orbit around Dinkinesh, making it a triple asteroid system. This triple asteroid system is unstable due to chaotic gravitational perturbations between the satellites, and eventually leads to one of the satellites colliding with either the primary asteroid or the other satellite. If the collision between two satellites occurs at slow enough speeds (less than 50 mm/s or 2.0 in/s), the impact does not disrupt the shapes of the two bodies and instead forms a contact binary.
Physical characteristics
Geology
The surfaces of Dinkinesh and Selam are covered with boulders and craters. The outline of Dinkinesh's shape is not smooth, which suggests that the asteroid is relatively old. Dinkinesh bears an equatorial ridge, which suggests that the asteroid has experienced mass shedding in the past. Dinkinesh's equatorial ridge also has a secondary ridge that branches off it. Dinkinesh's shape resembles the near-Earth asteroids 101955 Bennu and 162173 Ryugu, which are known to have rubble pile interior structures consisting of rocks and dust loosely held by gravity. Because of this similarity, Dinkinesh is thought to likely have a rubble pile structure as well.
A ridge is also present on Selam, but it is not oriented along its equator. The reason for Selam's unaligned ridge remains yet to be determined.
Surface composition
Visible light spectroscopy of Dinkinesh by two independent teams of researchers in November–December 2022 showed that it is an S-type asteroid, meaning it is mainly composed of rocky silicates and small amounts of metal. Spectral data obtained from the 10-meter Keck I telescope at Mauna Kea, Hawaii indicates that Dinkinesh belongs to the Sq subclass of S-type asteroids because it exhibits the 1 μm olivine and pyroxene spectral absorption band that is characteristically seen in Q-type asteroids. On the other hand, spectral data from the 8.1-meter Gemini South telescope at Cerro Pachón, Chile showed that Dinkinesh's spectrum more closely resembles a standard S-type asteroid with a shallower 1 μm band. This difference between the two measured spectra of Dinkinesh may be caused by either observational artifacts or compositional variations across Dinkinesh's surface as it rotates. If the latter possibility is true, then Dinkinesh's varying 1 μm band would indicate that there is space-weathered material that is unevenly distributed across its surface, likely due to impacts and surface topography.
Rotation and light curve
Dinkinesh rotates every 3.7387±0.0013 h. As Dinkinesh rotates, its brightness from Earth fluctuates due to its non-spherical shape, which can be inferred from the amplitude of the asteroid's rotational light curve. The first photometric observations of Dinkinesh's rotational light curve were attempted with the Teide Observatory's 0.8-m IAC-80 telescope at Tenerife, Spain in November 2022, but it did not observe Dinkinesh long enough to make conclusive findings. Longer photometric observations of Dinkinesh were made with the Calar Alto Observatory's 1.23-m telescope at Almería, Spain from November 2022–February 2023, which discovered that Dinkinesh rotates slowly and had a light curve amplitude of 0.39±0.02 magnitudes.
Diameter and albedo
Lucy images of Dinkinesh show that it measures approximately 790 m (2,590 ft) across its equator. This is in agreement with the previous diameter estimates from measured absolute magnitude and average S-type asteroid albedo. Reprocessing of archival infrared thermal emission observations by the Wide-field Infrared Survey Explorer (WISE) from March 2010 give a consistent result.
See also
- 52246 Donaldjohanson, Lucy's next flyby target in 2025
- List of minor planets and comets visited by spacecraft
References
- ^ "JPL Small-Body Database Browser: 152830 Dinkinesh (1999 VD57)" (2022-11-05 last obs.). Jet Propulsion Laboratory. Archived from the original on 18 November 2022. Retrieved 25 January 2023.
- ^ "(152830) Dinkinesh = 2004 HJ78 = 1999 VD57 = 2007 CB63". Minor Planet Center. Archived from the original on 13 March 2023. Retrieved 25 January 2023.
- ^ Kretke, Katherine (2 November 2023). "NASA's Lucy Spacecraft Discovers 2nd Asteroid During Dinkinesh Flyby". NASA. Archived from the original on 3 November 2023. Retrieved 2 November 2023.
- ^ Levison, Harold F.; Marchi, Simone; Noll, Keith S.; et al. (29 May 2024). "A contact binary satellite of the asteroid (152830) Dinkinesh". Nature. 629 (8014): 1015–1020. arXiv:2406.19337. Bibcode:2024Natur.629.1015L. doi:10.1038/s41586-024-07378-0. PMC 11136651. PMID 38811709.
- ^ McFadden, Kiana D.; Mainzer, Amy K.; Masiero, Joseph R.; Bauer, James M.; Cutri, Roc M.; Dahlen, Dar; et al. (November 2023). "Size and Albedo Constraints for (152830) Dinkinesh Using WISE Data". Astrophysical Journal Letters. 957 (1): 6. arXiv:2309.13158. Bibcode:2023ApJ...957L...2M. doi:10.3847/2041-8213/acff61. L2.
- ^ Bolin, B. T.; Noll, K. S.; Caiazzo, I.; Fremling, C.; Binzel, R. P. (August 2023). "Keck and Gemini spectral characterization of Lucy mission fly-by target (152830) Dinkinesh". Icarus. 400. arXiv:2303.08130. Bibcode:2023Icar..40015562B. doi:10.1016/j.icarus.2023.115562. S2CID 257505087. 115562.
- ^ de León, J.; Licandro, J.; Pinilla-Alonso, N.; Moskovitz, N.; Kareta, T.; Popescu, M.; et al. (April 2023). "Characterisation of the new target of the NASA Lucy mission: asteroid 152830 Dinkinesh (1999 VD57)". Astronomy & Astrophysics. 672: 4. arXiv:2303.05918. Bibcode:2023A&A...672A.174D. doi:10.1051/0004-6361/202346278. A174.
- ^ Mottola, Stephano; Denk, Tilmann; Marchi, Simone; Binzel, Richard P.; Noll, Keith S.; Spencer, John R.; Levison, Harold F. (September 2023). "Characterizing asteroid (152830) Dinkinesh in preparation for the encounter with the NASA Lucy mission: a photometric study". Monthly Notices of the Royal Astronomical Society: Letters. 524 (1): L1 – L4. Bibcode:2023MNRAS.524L...1M. doi:10.1093/mnrasl/slad066.
- ^ Kretke, Katherine (11 September 2023). "NASA's Lucy Spacecraft Captures its 1st Images of Asteroid Dinkinesh". NASA. Archived from the original on 15 September 2023. Retrieved 12 September 2023.
- "M. P. S. 7496" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 23 November 1999. p. 284. Archived (PDF) from the original on 13 September 2023. Retrieved 13 September 2023.
- "M. P. S. 105236" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 25 April 2004. p. 414. Archived (PDF) from the original on 28 August 2017. Retrieved 13 September 2023.
- "M. P. S. 200485" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 25 February 2007. p. 253. Archived (PDF) from the original on 4 October 2017. Retrieved 13 September 2023.
- "MPEC 2007-E01 : DAILY ORBIT UPDATE (2007 MAR. 2 UT)". Minor Planet Electronic Circulars. Minor Planet Center. 2 March 2007. Archived from the original on 8 November 2023. Retrieved 13 September 2023.
- ^ "M. P. O. 116514" (PDF). Minor Planet Circulars Orbit Supplement. Minor Planet Center. 2 April 2007. p. 96. Archived (PDF) from the original on 14 September 2016. Retrieved 13 September 2023.
- "M. P. S. 201406" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 3 March 2007. p. 10. Archived (PDF) from the original on 4 October 2017. Retrieved 13 September 2023.
- "M. P. O. 115681" (PDF). Minor Planet Circulars Orbit Supplement. Minor Planet Center. 3 March 2007. p. 839. Archived (PDF) from the original on 14 September 2016. Retrieved 13 September 2023.
- "M. P. C. 59323" (PDF). Minor Planet Circulars. Minor Planet Center. 2 April 2007. p. 47. Archived (PDF) from the original on 14 August 2016. Retrieved 13 September 2023.
- "M. P. O. 213622" (PDF). Minor Planet Circulars Supplement. Minor Planet Center. 19 August 2007. p. 620. Archived (PDF) from the original on 14 September 2016. Retrieved 13 September 2023.
- "M. P. C. 58994" (PDF). Minor Planet Circulars. Minor Planet Center. 3 March 2007. p. 4. Archived (PDF) from the original on 28 August 2017. Retrieved 13 September 2023.
- "M. P. C. 64979" (PDF). Minor Planet Circulars. Minor Planet Center. 9 February 2007. p. 9. Archived (PDF) from the original on 28 August 2017. Retrieved 13 September 2023.
- ^ Foust, Jeff (26 January 2023). "NASA adds asteroid flyby to Lucy mission". SpaceNews. Archived from the original on 8 November 2023. Retrieved 26 January 2023.
- ^ "WGSBN Bulletin 3, #2" (PDF). WGSBN Bulletin. 3 (2). International Astronomical Union: 22. 6 February 2023. Archived (PDF) from the original on 6 February 2023. Retrieved 6 February 2023.
- Kretke, Katherine (1 March 2023). "Introducing "Dinkinesh" – First Asteroid Target for NASA's Lucy Mission Gets a Name". SciTechDaily. Archived from the original on 2 March 2023. Retrieved 2 March 2023.
- "How to Say Wonderful in Amharic". Archived from the original on 29 October 2023. Retrieved 29 October 2023.
- "Helpful Amharic Words & Phrases" (PDF). Archived (PDF) from the original on 29 October 2023. Retrieved 29 October 2023.
- ^ Morton, Erin (1 November 2023). "NASAs Lucy Spacecraft Hours Away from 1st Asteroid Encounter". NASA Blogs. NASA. Archived from the original on 2 November 2023. Retrieved 1 November 2023.
- ^ Evans, Jessica (25 January 2023). "NASA's Lucy Team Announces New Asteroid Target". NASA. Archived from the original on 25 January 2023. Retrieved 25 January 2023.
- Spencer, J.; Levison, H.; Marchi, S.; Noll, K.; Salmon, J.; Marschall, R.; et al. (October 2023). The Lucy Encounter with (152830) Dinkinesh. 55th Annual DPS Meeting Joint with EPSC. Vol. 55. San Antonio, Texas. 102.06. Archived from the original on 8 November 2023. Retrieved 2 October 2023.
- Morton, Erin (18 May 2023). "NASA's Lucy Spacecraft Adjusts Course for Asteroid Flyby in November". NASA Blogs. NASA. Archived from the original on 28 October 2023. Retrieved 21 October 2023.
- Kretke, Katherine (13 October 2023). "NASA's Lucy Spacecraft Continues Approach to Asteroid Dinkinesh". NASA. Archived from the original on 19 October 2023. Retrieved 21 October 2023.
- ^ Spencer, J. R.; Levison, H. A.; Marchi, S.; Salmon, J. J.; Noll, K. S.; Solanki, I.; Olkin, C. A. (June 2023). Planning Close Encounter Science Observations for the Lucy Mission (PDF). Asteroids, Comets, Meteors Conference 2023. Lunar and Planetary Institute. 2456. Archived (PDF) from the original on 14 September 2023. Retrieved 12 September 2023.
- ^ "(152830) Dinkinesh and Selam". Johnston's Archive. Wm. Robert Johnston. Retrieved 27 March 2024.
- ^ "WGSBN Bulletin 3, #16" (PDF). WGSBN Bulletin. 3 (16). International Astronomical Union: 12. 27 November 2023. Archived (PDF) from the original on 28 November 2023. Retrieved 27 November 2023.
- ^ Morton, Erin (29 November 2023). "Satellite Discovered by NASA's Lucy Mission Gets Name". NASA Blogs. NASA. Archived from the original on 30 November 2023. Retrieved 29 November 2023.
- ^ Bartels, Meghan (3 November 2023). "NASA Asteroid Mission Discovers Tiny Surprise Moon with 'Really Bizarre' Shape". Scientific American. Archived from the original on 3 November 2023. Retrieved 3 November 2023.
- ^ Merrill, Colby; Kubas, Alexia; Meyer, Alex; Raducan, Sabina (2024). "Age of (152830) Dinkinesh I Selam constrained by secular tidal-BYORP theory". Astronomy and Astrophysics. 684: L20. Bibcode:2024A&A...684L..20M. doi:10.1051/0004-6361/202449716.
- "NASA's Lucy Mission Gets an Unexpected Twofer in First Asteroid Encounter". Johns Hopkins University Applied Physics Laboratory. 2 November 2023. Archived from the original on 3 November 2023. Retrieved 2 November 2023.
- Kretke, Katherine (7 November 2023). "NASA's Lucy Surprises Again, Observes 1st-ever Contact Binary Orbiting Asteroid". NASA. Archived from the original on 7 November 2023. Retrieved 7 November 2023.
- ^ Lakdawalla, Emily (3 November 2023). "Lucy Mission Flies By Asteroid Dinkinesh, Finds a Little Surprise". Sky & Telescope. Archived from the original on 3 November 2023. Retrieved 3 November 2023.
- Hyodo, Ryuki; Sugiura, Keisuke (October 2022). "Formation of Moons and Equatorial Ridge around Top-shaped Asteroids after Surface Landslide". The Astrophysical Journal Letters. 937 (2): 6. arXiv:2209.07045. Bibcode:2022ApJ...937L..36H. doi:10.3847/2041-8213/ac922d. S2CID 252280407. L36.
- ^ Jacobson, Seth A.; Scheeres, Daniel J. (July 2011). "Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems". Icarus. 214 (1): 161–178. arXiv:1404.0801. Bibcode:2011Icar..214..161J. doi:10.1016/j.icarus.2011.04.009. S2CID 119245876.
- Petersen, Collins (9 November 2023). "What? Wow! That New Asteroid Image from Lucy Just Got Even More Interesting". Universe Today. Archived from the original on 10 November 2023. Retrieved 9 November 2023.
- Palamakumbure, Lakshika; Mizohata, Kenichiro; Flanderová, Kateřina; Korda, David; Penttilä, Antti; Kouhout, Tomáš (April 2023). "Simulation of Space Weathering on Asteroid Spectra through Hydrogen Ion Irradiation of Meteorites". The Planetary Science Journal. 4 (4): 10. Bibcode:2023PSJ.....4...72P. doi:10.3847/PSJ/acc848. hdl:10138/358328. 72.
- ^ Mottola, S.; Denk, T.; Marchi, S.; Binzel, R. P.; Noll, K. S.; Spencer, J. R.; Levison, H. F. (June 2023). Pre-Encounter Characterization of the Lucy Target (152830) Dinkinesh (PDF). Asteroids, Comets, Meteors Conference 2023. Lunar and Planetary Institute. 2486. Archived (PDF) from the original on 1 July 2023. Retrieved 23 May 2023.
External links
- "Flyby of Dinkinesh Simulation". NASA's Eyes on the Solar System. NASA. Archived from the original on 2 November 2023.
- 152830 Dinkinesh at AstDyS-2, Asteroids—Dynamic Site
- 152830 Dinkinesh at the JPL Small-Body Database
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