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| {{Short description|A magnetar, a type of neutron star, with the most powerful magnetic field known}} | |||
| {{Starbox begin | {{Starbox begin | ||
| | name=SGR |
| name=SGR 1806−20}} | ||
| {{Starbox image |
{{Starbox image | ||
| | image = ] | | image = ] | ||
| | caption = |
| caption = SGR 1806-20 is located in the constellation ]. | ||
| }} |
}} | ||
| {{Starbox observe | {{Starbox observe | ||
| | epoch=J2000 | | epoch=J2000 | ||
| | ra=18h 08m 39.32s |
| ra=18h 08m 39.32s | ||
| | dec=−20° 24' 39.5"' | | dec=−20° 24' 39.5"' | ||
| | appmag_v= totally obscured | | appmag_v= totally obscured | ||
| | constell=] |
| constell=] | ||
| }} | |||
| {{Starbox astrometry | |||
| |- style="vertical-align: top;" | |||
| | dist_ly = 42,000 | |||
| | '''] ''' | |||
| | dist_pc = 13,000<ref name="ATNF">{{cite web |url=https://www.atnf.csiro.au/research/pulsar/psrcat/proc_form.php?version=1.66&Name=Name&JName=JName&RaJD=RaJD&DecJD=DecJD&P0=P0&Dist=Dist&startUserDefined=true&c1_val=&c2_val=&c3_val=&c4_val=&sort_attr=jname&sort_order=asc&condition=&pulsar_names=J1808-2024&ephemeris=short&coords_unit=raj%2Fdecj&radius=&coords_1=&coords_2=&style=Long+with+last+digit+error&no_value=*&fsize=3&x_axis=&x_scale=linear&y_axis=&y_scale=linear&state=query&table_bottom.x=31&table_bottom.y=25 |title=PSR J1808-2024 in the ATNF Pulsar Database |last1=Manchester |first1=R. N. |last2=Hobbs |first2=G.B. |last3=Teoh |first3=A. |last4=Hobbs |first4=M. |date= |website=atnf.csiro.edu |publisher=] |access-date=9 January 2022 |quote=}}</ref> | |||
| | 50,000 ]s (14.5 ]s) | |||
| }} | |||
| {{Starbox detail | |||
| <!-- | |||
| | mass=12.391 | |||
| | radius=0.000025 | |||
| | luminosity=3000000{{Citation needed|date=October 2015}} | |||
| --> | |||
| | rotation = 7.55592 ]<ref name="ATNF"/> | |||
| }} | |||
| {{Starbox catalog | {{Starbox catalog | ||
| | names= ] 790107, ] 84, ] 1805.7-2025 |
| names= ] 790107, ] 84, ], ] 882, ] J180839.3-202439, ] 1566, KONUS 07.01.79, EQ 1805.7-2025, ] 3801, ] J1808−2024, ] 1806-20, ] 3800, ] J1808.6−2024 | ||
| }} | |||
| {{Starbox reference | |||
| | Simbad = SGR+1806-20 | |||
| }} | |||
| {{Starbox end}} | {{Starbox end}} | ||
| '''SGR |
'''SGR 1806−20''' is a ], a type of ] with a very powerful magnetic field, that was discovered in 1979 and identified as a ]. SGR 1806−20 is located about 13 ]s (42,000 ]s)<ref name="ATNF"/> from Earth on the far side of the ] in the ] of ]. It has a ] of no more than {{convert|20|km|mi}} and rotates on its axis every 7.5 seconds ({{convert|30,000|km/h}} rotation speed at the equator on the surface). {{As of|2016}}, SGR 1806-20 is the most highly magnetized object ever observed, with a magnetic field of over 10<sup>15</sup> ] (G) (10<sup>11</sup> ]) intensity<ref>{{cite web|url=http://www.gsfc.nasa.gov/topstory/20021030strongestmag.html|title=Top story – Scientists measure the most powerful magnet known|publisher=NASA, Goddard Space Flight Center |date=2002-11-04|access-date=2011-12-29|url-status=dead|archive-url=https://web.archive.org/web/20100428073012/http://www.gsfc.nasa.gov/topstory/20021030strongestmag.html|archive-date=2010-04-28}}</ref> (compared to the Sun's 1–5 G and ] 0.25–0.65 G). | ||
| ==Explosion== | ==Explosion== | ||
| ] | |||
| On December 27, 2004, the radiation from an explosion on the surface of SGR 1806-20 reached ].<ref name="top">{{citeweb|url=http://www.gsfc.nasa.gov/topstory/20021030strongestmag.html|title=Top story – Scientists measure the most powerful magnet known|accessdate=14 December 2007}}</ref> In terms of gamma rays the burst had an absolute magnitude around −29{{ref|1|1}}. It was the brightest event known to have been sighted on this planet from an origin outside our solar system. The gamma rays struck the ] and created more ionization which briefly expanded the ionosphere. The magnetar released more energy in one-tenth of a second (1.3×10<sup>39</sup> ]) than our sun has released in 100,000 years (4×10<sup>26</sup> ] × 3.2×10<sup>12</sup> s = 1.3×10<sup>39</sup> J). Such a burst is thought to be the largest explosion observed by humans in the galaxy since the ] supernova observed by ] in 1604. | |||
| ]]] Forty-two thousand years after a ] occurred on the surface of SGR 1806-20, the radiation from the resultant explosion reached Earth on December 27, 2004 (]).<ref name="top">{{cite web|url=http://www.nasa.gov/vision/universe/watchtheskies/swift_nsu_0205.html|title=Cosmic Explosion Among the Brightest in Recorded History|publisher=NASA, Goddard Space Flight Center |date=2005-02-18|access-date=2011-12-29}}</ref> In terms of gamma rays, the burst had an absolute magnitude of around −29.{{efn|As measured by various space-based and land-based astronomical ], including the '']'' spacecraft.}} It was the brightest event known to have been sighted on this planet from an origin outside the ] until ]. The magnetar released more energy in one-tenth of a second (1.0{{e|40}} ]) than the Sun releases in 150,000 years (4{{e|26}} ] × 4.8{{e|12}} s = 1.85{{e|39}} J).<ref name="top" /> Such a burst is thought to be the largest explosion observed in this galaxy by humans since the ], a supernova observed by ] in 1604. The gamma rays struck Earth's ] and created more ionization, which briefly expanded the ionosphere. The quake was equivalent to a magnitude 32 on the ].<ref>{{Cite web |last=Plait |first=Phil |author-link=Phil Plait |date=2009-06-18 |title=OK, so maybe we can be a *little* frightened. |url=https://www.discovermagazine.com/the-sciences/ok-so-maybe-we-can-be-a-little-frightened |access-date=2024-05-13 |website=Discover Magazine |language=en}}</ref> | |||
| A similar blast within 3 parsecs (10 light years) of Earth would |
A similar blast within 3 parsecs (10 light years) of Earth would severely affect the atmosphere,<ref name="top" /> by destroying the ] and causing mass extinction,<ref name="Astronomy.com-Berman-2015">{{cite web |author1=Bob Berman |author1-link=Bob Berman |title=Weird Object: Magnetar SGR 1806-20 |url=https://astronomy.com/magazine/weirdest-objects/2015/09/17-magnetar-sgr-1806-20#:~:text=If%20it%20were%20located%20within,some%2050%2C000%20light%2Dyears%20away. |website=Astronomy.com |access-date=30 December 2020 |language=en |date=4 September 2015}}</ref><ref name="ScienceDaily-Blast Affected Earth-2005">{{cite web |title=Harvard-Smithsonian Center For Astrophysics: Blast Affected Earth From Halfway Across The Milky Way |url=https://www.sciencedaily.com/releases/2005/02/050222195452.htm |website=ScienceDaily |access-date=30 December 2020 |language=en |date=23 February 2005}}</ref> and be similar in effect to a 12-] nuclear blast at {{convert|7.5|km}}.{{citation needed|date=August 2019}} The nearest known magnetar to Earth is ], located 9,000 light-years away in the constellation ]. | ||
| ==Location== | ==Location== | ||
| SGR |
SGR 1806−20 lies at the core of radio nebula G10.0-0.3 and is a member of ] named after it, itself a component of ], one of the largest ]s in the Milky Way. Cluster 1806-20 is made up of some highly unusual stars, including at least two carbon-rich ]s (WC9d and WCL), two blue ], and ], one of the brightest/most massive stars in the galaxy. | ||
| ==Planetary system== | |||
| A 2024 paper posited that periodic gamma-ray and x-ray bursts from the pulsar are caused by a planet orbiting SGR 1806-20. This SGR 1806-20 b would be some kind of rocky world with a mass between 10-18 ] with an orbital period of 398 days and a semi-major axis of 1.18 ]. SGR 1806-20 b is notable for its eccentricity of 0.994, which would make it the most eccentric exoplanet known.<ref>https://exoplanet.eu/catalog/sgr_1806_20_b--10023/</ref><ref>{{cite journal |last1=Kurban |first1=Abdusattar |last2=Zhou |first2=Xia |last3=Wang |first3=Na |last4=Huang |first4=Yong-Feng |last5=Wang |first5=Yu-Bin |last6=Nurmamat |first6=Nurimangul |date=3 June 2024 |title=Repeating X-ray bursts: Interaction between a neutron star and clumps partially disrupted from a planet |journal=Astronomy & Astrophysics |volume=686 |pages=A87 |doi=10.1051/0004-6361/202347828 |url=https://www.aanda.org/articles/aa/full_html/2024/06/aa47828-23/aa47828-23.html |arxiv=2403.13333}}</ref> | |||
| ==See also== | ==See also== | ||
| * ] |
* ] – ] | ||
| * ] –- ] | |||
| ⚫ | |||
| * ] | |||
| ==Notes== | ==Notes== | ||
| {{notelist}} | |||
| :*{{note|1|1}} As measured by various space-based and land-based astronomical ], including the '']'' spacecraft. | |||
| ==References== | ==References== | ||
| {{Reflist}} | {{Reflist}} | ||
| * | |||
| ==External links== | ==External links== | ||
| {{Commons category}} | |||
| ⚫ | *, 2005-04-28 (]) | ||
| * (] Dec. 27, 2012) | |||
| ⚫ | *, 2005-02-18, (]) |
||
| ⚫ | *, 2005-04-28 ('']'') | ||
| ⚫ | *, 2005-02-18, (]) | ||
| * 2005-02-18 (]) | * 2005-02-18 (]) | ||
| * 2005-02-20 (]) '''Registration required.''' | * 2005-02-20 ('']'') '''Registration required.''' | ||
| * 2005-09-27 (space.com) | * 2005-09-27 (space.com) | ||
| * (SpaceDaily) April 26, 2006 | * (''SpaceDaily'') April 26, 2006 | ||
| {{Sky|18|08|39.32|-|20|24|39.5|50000}} | {{Sky|18|08|39.32|-|20|24|39.5|50000}} | ||
| ⚫ | {{Sagittarius (constellation)}} | ||
| {{DEFAULTSORT:Sgr 1806-20}} | |||
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| {{DEFAULTSORT:SGR 1806-20}} | |||
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Latest revision as of 19:02, 3 January 2025
A magnetar, a type of neutron star, with the most powerful magnetic field known SGR 1806-20 is located in the constellation Sagittarius. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 08m 39.32s |
| Declination | −20° 24' 39.5"' |
| Apparent magnitude (V) | totally obscured |
| Astrometry | |
| Distance | 42,000 ly (13,000 pc) |
| Details | |
| Rotation | 7.55592 s |
| Other designations | |
| GRB 790107, INTEGRAL1 84, AX 1805.7-2025 GRB 970912, INTREF 882, CXOU J180839.3-202439, HETE Trigger 1566, KONUS 07.01.79, EQ 1805.7-2025, HETE Trigger 3801, PSR J1808−2024, GBS 1806-20, HETE Trigger 3800, RX J1808.6−2024 | |
| Database references | |
| SIMBAD | data |
SGR 1806−20 is a magnetar, a type of neutron star with a very powerful magnetic field, that was discovered in 1979 and identified as a soft gamma repeater. SGR 1806−20 is located about 13 kiloparsecs (42,000 light-years) from Earth on the far side of the Milky Way in the constellation of Sagittarius. It has a diameter of no more than 20 kilometres (12 mi) and rotates on its axis every 7.5 seconds (30,000 kilometres per hour (19,000 mph) rotation speed at the equator on the surface). As of 2016, SGR 1806-20 is the most highly magnetized object ever observed, with a magnetic field of over 10 gauss (G) (10 tesla) intensity (compared to the Sun's 1–5 G and Earth's 0.25–0.65 G).
Explosion
Forty-two thousand years after a starquake occurred on the surface of SGR 1806-20, the radiation from the resultant explosion reached Earth on December 27, 2004 (GRB 041227). In terms of gamma rays, the burst had an absolute magnitude of around −29. It was the brightest event known to have been sighted on this planet from an origin outside the Solar System until GRB 080319B. The magnetar released more energy in one-tenth of a second (1.0×10 J) than the Sun releases in 150,000 years (4×10 W × 4.8×10 s = 1.85×10 J). Such a burst is thought to be the largest explosion observed in this galaxy by humans since the SN 1604, a supernova observed by Johannes Kepler in 1604. The gamma rays struck Earth's ionosphere and created more ionization, which briefly expanded the ionosphere. The quake was equivalent to a magnitude 32 on the Richter scale.
A similar blast within 3 parsecs (10 light years) of Earth would severely affect the atmosphere, by destroying the ozone layer and causing mass extinction, and be similar in effect to a 12-kiloton nuclear blast at 7.5 kilometres (4.7 mi). The nearest known magnetar to Earth is 1E 1048.1-5937, located 9,000 light-years away in the constellation Carina.
Location
SGR 1806−20 lies at the core of radio nebula G10.0-0.3 and is a member of an open cluster named after it, itself a component of W31, one of the largest H II regions in the Milky Way. Cluster 1806-20 is made up of some highly unusual stars, including at least two carbon-rich Wolf–Rayet stars (WC9d and WCL), two blue hypergiants, and LBV 1806-20, one of the brightest/most massive stars in the galaxy.
Planetary system
A 2024 paper posited that periodic gamma-ray and x-ray bursts from the pulsar are caused by a planet orbiting SGR 1806-20. This SGR 1806-20 b would be some kind of rocky world with a mass between 10-18 Earth masses with an orbital period of 398 days and a semi-major axis of 1.18 astronomical units. SGR 1806-20 b is notable for its eccentricity of 0.994, which would make it the most eccentric exoplanet known.
See also
Notes
- As measured by various space-based and land-based astronomical observatories, including the Swift spacecraft.
References
- ^ Manchester, R. N.; Hobbs, G.B.; Teoh, A.; Hobbs, M. "PSR J1808-2024 in the ATNF Pulsar Database". atnf.csiro.edu. Australia Telescope National Facility. Retrieved 9 January 2022.
- "Top story – Scientists measure the most powerful magnet known". NASA, Goddard Space Flight Center. 2002-11-04. Archived from the original on 2010-04-28. Retrieved 2011-12-29.
- ^ "Cosmic Explosion Among the Brightest in Recorded History". NASA, Goddard Space Flight Center. 2005-02-18. Retrieved 2011-12-29.
- Plait, Phil (2009-06-18). "OK, so maybe we can be a *little* frightened". Discover Magazine. Retrieved 2024-05-13.
- Bob Berman (4 September 2015). "Weird Object: Magnetar SGR 1806-20". Astronomy.com. Retrieved 30 December 2020.
- "Harvard-Smithsonian Center For Astrophysics: Blast Affected Earth From Halfway Across The Milky Way". ScienceDaily. 23 February 2005. Retrieved 30 December 2020.
- https://exoplanet.eu/catalog/sgr_1806_20_b--10023/
- Kurban, Abdusattar; Zhou, Xia; Wang, Na; Huang, Yong-Feng; Wang, Yu-Bin; Nurmamat, Nurimangul (3 June 2024). "Repeating X-ray bursts: Interaction between a neutron star and clumps partially disrupted from a planet". Astronomy & Astrophysics. 686: A87. arXiv:2403.13333. doi:10.1051/0004-6361/202347828.
External links
- Anniversary of a Cosmic Blast (Phil Plait Dec. 27, 2012)
- An exceptionally bright flare from SGR 1806-20 and the origins of short-duration big gamma-ray bursts, 2005-04-28 (Nature)
- Huge 'star-quake' rocks Milky Way, 2005-02-18, (BBC News Online)
- Brightest galactic flash ever detected hits Earth 2005-02-18 (space.com)
- 2005-02-20 (The Age) Registration required.
- Huge quake cracks star 2005-09-27 (space.com)
- NASA Sees Hidden Structure Of Neutron Star In Starquake (SpaceDaily) April 26, 2006
