Old page wikitext, before the edit (old_wikitext ) | '{{Use dmy dates|date=January 2015}}
{{Short description|Triple star system in the constellation of Lyra}}
{{Starbox begin
| name = Kepler-444
}}
{{Starbox observe
| epoch = J2000
| equinox = 2000
| constell = [[Lyra (constellation)|Lyra]]
| ra = {{RA|19|19|00.5488}}<ref name="Gaia DR2"/>
| dec = {{DEC|+41|38|04.5816}}<ref name="Gaia DR2"/>
| appmag_v =8.86<ref name=ducati2002/>
}}
{{Starbox character
| class = K0V<ref name=wilson1962/>
}}
{{Starbox astrometry
| radial_v = {{val|-123.05|0.17}}<ref name="Dupuy2016"/>
| prop_mo_ra = {{val|94.682|0.055}}<ref name="Gaia DR2"/>
| prop_mo_dec = {{val|−632.202|0.051}}<ref name="Gaia DR2"/>
| parallax = 27.4137
| p_error = 0.0295
| parallax_footnote = <ref name="Gaia DR2"/>
| absmag_v =
}}
{{Starbox orbit
| reference = <ref name=Zhang2023/>
| primary = A
| name = BC
| axis_unitless = {{val|52.2|+3.3|−2.7}} AU
| eccentricity = {{val|0.55|+0.05|−0.05}}
| inclination = {{val|85.4|+0.3|−0.4}}
| node = {{val|250.7|+0.2|−0.2}}
| periarg = {{val|227.3|+6.5|−5.2}}
| period = {{val|324|+31|−25}}
| periastron = JD {{val|2537060|+10881|−8533}}
}}
{{Starbox detail
| component1 = A
| mass = {{val|0.754|0.030}}<ref name="Buldgen2019"/>
| radius = {{val|0.753|0.010}}<ref name="Buldgen2019"/>
| luminosity_bolometric =
| temperature = {{val|5046|74.0}}<ref name="Campante2015"/>
| gravity = {{val|4.595|0.060}}<ref name="Campante2015"/>
| metal_fe = {{val|−0.55|0.07}}<ref name="Campante2015"/>
| rotation = {{val|49.40|6.04|u=days}}<ref name="Mazeh2015"/>
| age_gyr = {{val|11.00|0.8}}<ref name="Buldgen2019"/>
}}
{{Starbox detail |no_heading=y
| component1 = B
| mass = {{val|0.307|0.009|0.008}}<ref name=Zhang2023/>
| temperature = {{val|3,464|200|fmt=commas}}<ref name="Campante2015"/>
| gravity = {{val|5.0|0.2}}<ref name="Campante2015"/>
| component2 = C
| mass2 = {{val|0.296|0.008}}<ref name=Zhang2023/>
| temperature2 = 3,500 - 4,000<ref name="Campante2015"/>
| gravity2 = ~5<ref name="Campante2015"/>
}}
{{Starbox catalog
| names = {{odlist | 2MASS=J19190052+4138043 | BD=+41°3306 | KIC=6278762 | KOI=3158 | WDS=J19190+4138 }}
| component1 = Kepler-444A
| names1 = {{odlist | 2MASS=J19190052+4138043 | Gaia DR2=2101486923385239808 | HIP=94931 | LHS=3450 | TYC=3129-00329-1 }}<ref name="Simbad for A"/>
| component2 = Kepler-444BC
| names2 = {{odlist | Gaia DR2=2101486923382009472 }}<ref name="Simbad for B"/>
}}
{{Starbox reference
| Simbad = KOI-3158
| Simbad2 = KOI+3158B |sn2=B/C
}}
{{Starbox end}}
'''Kepler-444''' (or '''KOI-3158''', '''KIC 6278762''', '''2MASS J19190052+4138043''', '''BD+41°3306''')<ref name="Simbad for A"/> is a [[triple star system]], estimated to be 11.2 billion years old (more than 80% of the age of the [[universe]]),<ref name="SP-20150127" /> approximately {{convert|119|ly|pc}} away from [[Earth]] in the [[constellation]] [[Lyra (constellation)|Lyra]]. On 27 January 2015, the [[Kepler (spacecraft)|''Kepler'' spacecraft]] is reported to have confirmed the detection of five sub-Earth-sized [[Rocky planet|rocky]] [[exoplanets]] orbiting the main star. The star is a [[K-type main sequence star]].<ref name="NASA-20150128"/><ref name="AP-20150127"/><ref name="UT-20150127"/><ref name="SP-20150127"/><ref name="EX-20150127"/> All of the planets are far too close to their star to harbour life forms.<ref name="NASA-20150128" />
==Discovery==
Preliminary results of the planetary system around Kepler-444 were first announced at the second [[Kepler space telescope|Kepler Science Conference]] in 2013. At that conference, the star was known as KOI-3158.<ref name="CAL-201311"/>
==Characteristics==
The star, Kepler-444, is approximately 11.2 billion years old, whereas the [[Sun]] is only 4.6 billion years old. The age is that of Kepler-444 A, an [[Main sequence|orange main sequence star]] of spectral type K0.<ref name="SL-20140128"/> Despite this great age, it is in middle of its main-sequence lifespan, much like the Sun.
The original research on Kepler-444 was published in ''[[The Astrophysical Journal]]'' on 27 January 2015 under the title "An ancient extrasolar system with five sub-Earth-size planets" by a team of 40 authors, the abstract reads as follows:<ref name="Campante2015"/>
<blockquote>The chemical composition of stars hosting small exoplanets (with radii less than four Earth radii) appears to be more diverse than that of [[Gas giant|gas-giant hosts]], which tend to be [[Metallicity|metal-rich]]. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were more scarce. We report Kepler spacecraft observations of Kepler-444, a metal-poor Sun-like star from the old population of the [[Thick disk|Galactic thick disk]] and the host to a compact system of five transiting planets with sizes between those of Mercury and Venus. We validate this system as a true five-planet system orbiting the target star and provide a detailed characterization of its planetary and orbital parameters based on an analysis of the [[transit photometry]]. Kepler-444 is the densest star with detected solar-like oscillations. We use [[asteroseismology]] to directly measure a precise age of 11.2+/-1.0 Gyr for the host star, indicating that Kepler-444 formed when the Universe was less than 20% of its current age and making it the oldest known system of [[Terrestrial planet|terrestrial-size planets]]. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, leaving open the possibility for the existence of ancient life in the [[Galaxy]]. The age of Kepler-444 not only suggests that thick-disk stars were among the hosts to the first Galactic planets, but may also help to pinpoint the beginning of the era of [[planet formation]]." The star is believed to have 2 M dwarfs in orbit around it with the fainter companion 1.8 arc-seconds from the main star.
</blockquote>
==Stellar system==
The Kepler-444 system consists of the planet hosting primary and a pair of M-dwarf stars. The M-dwarfs orbit each other at a distance of less than 0.3 [[Astronomical unit|AU]] while the pair orbits the primary in a highly [[Orbital eccentricity|eccentric]] 324-year orbit. The pair comes within 23.55 AU of the primary potentially truncating the protoplanetary disk from which the planets formed at 8 AU. This would have depleted the availability of solid material to form the observed planets.<ref name="Zhang2023"/>
Previous stellar orbit solution was ever more extreme, period was shorter (211 years) and eccentricity was much larger (e=0.865), moving periastron to 5 AU, severely reducing the estimated protoplanetary disk size to 1–2 AU and its estimated mass from 600 to 4 Earth masses.<ref name="Dupuy2016"/>
==Planetary system==
All five rocky exoplanets (Kepler-444b; Kepler-444c; Kepler-444d; Kepler-444e; Kepler-444f) are confirmed,<ref name="EX-20150127" /> smaller than the size of [[Venus]] (but bigger than [[Mercury (planet)|Mercury]]) and each of the exoplanets completes an orbit around the host star in less than 10 days.<ref name="NASA-20150128" /><ref name="SP-20150127" /> Thus, the planetary system is very compact, as even the furthest known planet, Kepler-444f, still orbits closer to the star than Mercury is to the [[Sun]].<ref name="SL-20140128" /> According to NASA, no life as we know it could exist on these hot exoplanets, due to their close orbital distances to the host star.<ref name="NASA-20150128" /> To keep the known planetary system stable, no additional giant planets can be located within 5.5 [[astronomical unit|AU]] of the parent star.<ref>{{citation|arxiv=1702.07714|title=Effects of Unseen Additional Planetary Perturbers on Compact Extrasolar Planetary Systems|year=2017|doi=10.1093/mnras/stx461|last1=Becker|first1=Juliette C.|last2=Adams|first2=Fred C.|journal=Monthly Notices of the Royal Astronomical Society|volume=468|issue=1|pages=549–563|bibcode=2017MNRAS.468..549B|s2cid=119325005}}</ref>
Moreover, the system is pervaded by high-order resonance chain: period ratios are 4:5, 3:4, 4:5, 4:5. This tight chain is unperturbed and very likely continues farther from Kepler-444A.
{{OrbitboxPlanet begin
| table_ref = <ref name="EX-20150127" /><ref name="Mills2017"/>
}}
{{OrbitboxPlanet
| exoplanet = b
| mass_earth =
| semimajor = 0.04178
| period = {{val|3.600105|0.000031|0.000037}}
| eccentricity = 0.16
| inclination = 88
| radius_earth = 0.406{{±|0.013}}
}}
{{OrbitboxPlanet
| exoplanet = c
| mass_earth =
| semimajor = 0.04881
| period = 4.545876{{±|0.000031}}
| eccentricity = 0.31
| inclination = 88.2
| radius_earth = 0.521{{±|0.017}}
}}
{{OrbitboxPlanet
| exoplanet = d
| mass_earth = {{val|0.036|0.065|0.020}}
| semimajor = 0.06
| period = {{val|6.189437|0.000053|0.000037}}
| eccentricity = 0.18
| inclination = 88.16
| radius_earth = 0.54{{±|0.017}}
}}
{{OrbitboxPlanet
| exoplanet = e
| mass_earth = {{val|0.034|0.059|0.019}}
| semimajor = 0.0696
| period = {{val|7.743467|0.00006|0.0001}}
| eccentricity = 0.1
| inclination = 89.13
| radius_earth = {{val|0.555|0.018|0.016}}
}}
{{OrbitboxPlanet
| exoplanet = f
| mass_earth =
| semimajor = 0.0811
| period = {{val|9.740501|0.000078|0.000026}}
| eccentricity = 0.29
| inclination = 87.96
| radius_earth = 0.767{{±|0.025}}
}}
{{Orbitbox end}}
<!---
{{wide image|LombergA1024.jpg|600px|align-cap=center|The ''[[Kepler (spacecraft)|Kepler Space Telescope]]'' search volume, in the context of the [[Milky Way Galaxy]].}}
--->
{{-}}
==See also==
* [[Kepler-80]] - most compact 5-planet system discovered so far
* [[Lists of exoplanets|List of extrasolar planets]]
* [[PSR B1620-26]] - an ancient planetary system in [[Messier 4]]
==References==
{{Reflist|refs=
<ref name="Buldgen2019">{{cite journal | title=Revisiting Kepler-444. I. Seismic modeling and inversions of stellar structure | last1=Buldgen | first1=G. | last2=Farnir | first2=M. | last3=Pezzotti | first3=C. | last4=Eggenberger | first4=P. | last5=Salmon | first5=S. J. A. J. | last6=Montalban | first6=J. | last7=Ferguson | first7=J. W. | last8=Khan | first8=S. | last9=Bourrier | first9=V. | last10=Rendle | first10=B. M. | last11=Meynet | first11=G. | last12=Miglio | first12=A. | last13=Noels | first13=A. | display-authors=1 | journal=Astronomy & Astrophysics | volume=630 | at=A126 | year=2019 | arxiv=1907.10315 | bibcode=2019A&A...630A.126B | doi=10.1051/0004-6361/201936126 | s2cid=198229778 }}</ref>
<ref name="Campante2015">{{cite journal | title=An Ancient Extrasolar System with Five Sub-Earth-size Planets | last1=Campante | first1=T. L. | last2=Barclay | first2=T. | last3=Swift | first3=J. J. | last4=Huber | first4=D. | last5=Adibekyan | first5=V. Zh. | last6=Cochran | first6=W. | last7=Burke | first7=C. J. | last8=Isaacson | first8=H. | last9=Quintana | first9=E. V. | last10=Davies | first10=G. R. | last11=Silva Aguirre | first11=V. | last12=Ragozzine | first12=D. | last13=Riddle | first13=R. | last14=Baranec | first14=C. | last15=Basu | first15=S. | last16=Chaplin | first16=W. J. | last17=Christensen-Dalsgaard | first17=J. | last18=Metcalfe | first18=T. S. | last19=Bedding | first19=T. R. | last20=Handberg | first20=R. | last21=Stello | first21=D. | last22=Brewer | first22=J. M. | last23=Hekker | first23=S. | last24=Karoff | first24=C. | last25=Kolbl | first25=R. | last26=Law | first26=N. M. | last27=Lundkvist | first27=M. | last28=Miglio | first28=A. | last29=Rowe | first29=J. F. | last30=Santos | first30=N. C. | last31=Van Laerhoven | first31=C. | last32=Arentoft | first32=T. | last33=Elsworth | first33=Y. P. | last34=Fischer | first34=D. A. | last35=Kawaler | first35=S. D. | last36=Kjeldsen | first36=H. | last37=Lund | first37=M. N. | last38=Marcy | first38=G. W. | last39=Sousa | first39=S. G. | last40=Sozzetti | first40=A. | last41=White | first41=T. R. | display-authors=1 | journal=The Astrophysical Journal | volume=799 | issue=2 | at=170 | year=2015 | arxiv=1501.06227 | bibcode=2015ApJ...799..170C | bibcode-access=free | doi=10.1088/0004-637X/799/2/170 | doi-access=free }}</ref>
<ref name="Dupuy2016">{{cite journal | title=Orbital Architectures of Planet-Hosting Binaries. I. Forming Five Small Planets in the Truncated Disk of Kepler-444A | last1=Dupuy | first1=Trent J. | last2=Kratter | first2=Kaitlin M. | last3=Kraus | first3=Adam L. | last4=Isaacson | first4=Howard | last5=Mann | first5=Andrew W. | last6=Ireland | first6=Michael J. | last7=Howard | first7=Andrew W. | last8=Huber | first8=Daniel | display-authors=1 | journal=The Astrophysical Journal | volume=817 | issue=1 | at=80 | year=2016 | arxiv=1512.03428 | bibcode=2016ApJ...817...80D | bibcode-access=free | doi=10.3847/0004-637X/817/1/80 | doi-access=free }}</ref>
<ref name="Gaia DR2">{{Cite Gaia DR2|2101486923385239808}}</ref>
<ref name="Mazeh2015">{{cite journal | title=Photometric Amplitude Distribution of Stellar Rotation of KOIs—Indication for Spin-Orbit Alignment of Cool Stars and High Obliquity for Hot Stars | last1=Mazeh | first1=Tsevi | last2=Perets | first2=Hagai B. | last3=McQuillan | first3=Amy | last4=Goldstein | first4=Eyal S. | display-authors=1 | journal=The Astrophysical Journal | volume=801 | issue=1 | at=3 | year=2015 | arxiv=1501.01288 | bibcode=2015ApJ...801....3M | bibcode-access=free | doi=10.1088/0004-637X/801/1/3 | doi-access=free }}</ref>
<ref name="Mills2017">{{cite journal | title=Mass, Density, and Formation Constraints in the Compact, Sub-Earth Kepler-444 System including Two Mars-mass Planets | last1=Mills | first1=Sean M. | last2=Fabrycky | first2=Daniel C. | journal=The Astrophysical Journal Letters | volume=838 | issue=1 | at=L11 | year=2017 | arxiv=1703.03417 | bibcode=2017ApJ...838L..11M | bibcode-access=free | doi=10.3847/2041-8213/aa6543 | doi-access=free }}</ref>
<ref name="Simbad for A">{{cite simbad | title=BD+41 3306 | access-date=2020-08-20 }}</ref>
<ref name="Simbad for B">{{cite simbad | title=BD+41 3306B | access-date=2020-08-20 }}</ref>
<ref name="NASA-20150128">{{cite web |last=Johnson |first=Michele |title=Astronomers Discover Ancient System with Five Small Planets |url=http://www.nasa.gov/ames/kepler/astronomers-discover-ancient-system-with-five-small-planets |date=28 January 2015 |work=[[NASA]] |access-date=29 January 2015}}</ref>
<ref name="AP-20150127">{{cite news |last=Dunn |first=Marcia |title=Astronomers find solar system more than double ours in age |url=http://apnews.excite.com/article/20150127/us-sci--old_solar_system-56b7594709.html |date=27 January 2015 |work=[[AP News]] |access-date=27 January 2015}}</ref>
<ref name="UT-20150127">{{cite web |last1=Atkinson |first1=Nancy |title=Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere |url=http://www.universetoday.com/118510/oldest-planetary-system-discovered-improving-the-chances-for-intelligent-life-everywhere/ |date=27 January 2015 |work=[[Universe Today]] |access-date=27 January 2015}}</ref>
<ref name="SP-20150127">{{cite web |last=Wall |first=Mike |title=Found! 5 Ancient Alien Planets Nearly As Old As the Universe |url=http://www.space.com/28386-ancient-alien-planets-discovery-kepler-444.html |date=27 January 2015 |work=[[Space.com]] |access-date=27 January 2015}}</ref>
<ref name="EX-20150127">{{cite encyclopedia |author=Staff |title=Exoplanet Catalog |url=http://exoplanet.eu/catalog/ |date=27 January 2015 |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |access-date=27 January 2015}}</ref>
<ref name="CAL-201311">{{cite web |author=Staff |title=Second Kepler Science Conference - NASA Ames Research Center, Mountain View, CA - Nov. 4-8, 2013 - Agenda |url=http://nexsci.caltech.edu/conferences/KeplerII/agenda.shtml |date=8 November 2013 |work=[[Caltech]] |access-date=28 January 2014}}</ref>
<ref name="SL-20140128">{{cite news |last=Phil |first=Plait |author-link=Phil Plait |title=Astronomers Find Ancient Earth-Sized Planets in Our Galactic Backyard |url=http://www.slate.com/blogs/bad_astronomy/2015/01/27/exoplanets_five_extremely_old_planets_found_around_kepler_444.html |date=28 January 2015 |work=[[Slate (magazine)|Slate]] |access-date=28 January 2015}}</ref> is more than 80% of the [[age of the universe]].
<ref name=wilson1962>{{cite journal |bibcode=1962ApJ...136..793W |title=Relationship Between Colors and Spectra of Late Main-Sequence Stars |last1=Wilson |first1=O. C. |journal=The Astrophysical Journal |year=1962 |volume=136 |page=793 |doi=10.1086/147437 }}</ref>
<ref name=ducati2002>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati, J. R.|year=2002}}</ref</ref>>
<!--
<ref name=Stalport2022>{{cite journal | arxiv=2209.06810 | doi=10.1051/0004-6361/202243971 | bibcode=2022A&A...667A.128S | title=Global dynamics and architecture of the Kepler-444 system | year=2022 | last1=Stalport | first1=M. | last2=Matthews | first2=E. C. | last3=Bourrier | first3=V. | last4=Leleu | first4=A. | last5=Delisle | first5=J.-B. | last6=Udry | first6=S. | journal=Astronomy & Astrophysics | volume=667 | pages=A128 | s2cid=252222215 }}</ref>
-->
<ref name=Zhang2023>{{cite journal |doi=10.3847/1538-3881/aca88c |title=The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-planet Host System Kepler-444 |year=2023 |last1=Zhang |first1=Zhoujian |last2=Bowler |first2=Brendan P. |last3=Dupuy |first3=Trent J. |last4=Brandt |first4=Timothy D. |last5=Brandt |first5=G. Mirek |last6=Cochran |first6=William D. |last7=Endl |first7=Michael |last8=MacQueen |first8=Phillip J. |last9=Kratter |first9=Kaitlin M. |last10=Isaacson |first10=Howard T. |last11=Franson |first11=Kyle |last12=Kraus |first12=Adam L. |last13=Morley |first13=Caroline V. |last14=Zhou |first14=Yifan |journal=The Astronomical Journal |volume=165 |issue=2 |page=73 |arxiv=2210.07252 |bibcode=2023AJ....165...73Z |s2cid=252907948 }}</ref>
}}
==External links==
* [http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=KOI-3158 NASA – Kepler-444/KOI-3158] at [[NASA Exoplanet Archive|The NASA Exoplanet Archive]]
* [http://exoplanet.eu/catalog/kepler-444_b/ NASA – Kepler-444'''b''']/[http://exoplanet.eu/catalog/kepler-444_c/ '''c''']/[http://exoplanet.eu/catalog/kepler-444_d/ '''d''']/[http://exoplanet.eu/catalog/kepler-444_e/ '''e''']/[http://exoplanet.eu/catalog/kepler-444_f/ '''f'''] at [[The Extrasolar Planets Encyclopaedia|Extrasolar Planets Encyclopaedia]]
{{Stars of Lyra}}
{{2015 in space}}
{{Portal bar|Astronomy|Biology}}
{{Sky|19|19|01.0|+|41|38|05|117}}
[[Category:Lyra (constellation)]]
[[Category:Planetary systems with five confirmed planets]]
[[Category:K-type main-sequence stars]]
[[Category:Kepler objects of interest|3158]]
[[Category:Planetary transit variables]]
[[Category:2MASS objects|J19190052+4138043]]
[[Category:Hipparcos objects|94931]]
[[Category:Durchmusterung objects]]
[[Category:M-type main-sequence stars]]
[[Category:Triple star systems]]
[[Category:TIC objects]]' |
Unified diff of changes made by edit (edit_diff ) | '@@ -1,214 +1,2 @@
-{{Use dmy dates|date=January 2015}}
-{{Short description|Triple star system in the constellation of Lyra}}
-{{Starbox begin
-| name = Kepler-444
-}}
-{{Starbox observe
-| epoch = J2000
-| equinox = 2000
-| constell = [[Lyra (constellation)|Lyra]]
-| ra = {{RA|19|19|00.5488}}<ref name="Gaia DR2"/>
-| dec = {{DEC|+41|38|04.5816}}<ref name="Gaia DR2"/>
-| appmag_v =8.86<ref name=ducati2002/>
-}}
-{{Starbox character
-| class = K0V<ref name=wilson1962/>
-}}
-{{Starbox astrometry
-| radial_v = {{val|-123.05|0.17}}<ref name="Dupuy2016"/>
-| prop_mo_ra = {{val|94.682|0.055}}<ref name="Gaia DR2"/>
-| prop_mo_dec = {{val|−632.202|0.051}}<ref name="Gaia DR2"/>
-| parallax = 27.4137
-| p_error = 0.0295
-| parallax_footnote = <ref name="Gaia DR2"/>
-| absmag_v =
-}}
-{{Starbox orbit
-| reference = <ref name=Zhang2023/>
-| primary = A
-| name = BC
-| axis_unitless = {{val|52.2|+3.3|−2.7}} AU
-| eccentricity = {{val|0.55|+0.05|−0.05}}
-| inclination = {{val|85.4|+0.3|−0.4}}
-| node = {{val|250.7|+0.2|−0.2}}
-| periarg = {{val|227.3|+6.5|−5.2}}
-| period = {{val|324|+31|−25}}
-| periastron = JD {{val|2537060|+10881|−8533}}
-}}
-{{Starbox detail
-| component1 = A
-| mass = {{val|0.754|0.030}}<ref name="Buldgen2019"/>
-| radius = {{val|0.753|0.010}}<ref name="Buldgen2019"/>
-| luminosity_bolometric =
-| temperature = {{val|5046|74.0}}<ref name="Campante2015"/>
-| gravity = {{val|4.595|0.060}}<ref name="Campante2015"/>
-| metal_fe = {{val|−0.55|0.07}}<ref name="Campante2015"/>
-| rotation = {{val|49.40|6.04|u=days}}<ref name="Mazeh2015"/>
-| age_gyr = {{val|11.00|0.8}}<ref name="Buldgen2019"/>
-}}
-{{Starbox detail |no_heading=y
-| component1 = B
-| mass = {{val|0.307|0.009|0.008}}<ref name=Zhang2023/>
-| temperature = {{val|3,464|200|fmt=commas}}<ref name="Campante2015"/>
-| gravity = {{val|5.0|0.2}}<ref name="Campante2015"/>
-| component2 = C
-| mass2 = {{val|0.296|0.008}}<ref name=Zhang2023/>
-| temperature2 = 3,500 - 4,000<ref name="Campante2015"/>
-| gravity2 = ~5<ref name="Campante2015"/>
-}}
-{{Starbox catalog
-| names = {{odlist | 2MASS=J19190052+4138043 | BD=+41°3306 | KIC=6278762 | KOI=3158 | WDS=J19190+4138 }}
-| component1 = Kepler-444A
-| names1 = {{odlist | 2MASS=J19190052+4138043 | Gaia DR2=2101486923385239808 | HIP=94931 | LHS=3450 | TYC=3129-00329-1 }}<ref name="Simbad for A"/>
-| component2 = Kepler-444BC
-| names2 = {{odlist | Gaia DR2=2101486923382009472 }}<ref name="Simbad for B"/>
-}}
-{{Starbox reference
-| Simbad = KOI-3158
-| Simbad2 = KOI+3158B |sn2=B/C
-}}
-{{Starbox end}}
-
-'''Kepler-444''' (or '''KOI-3158''', '''KIC 6278762''', '''2MASS J19190052+4138043''', '''BD+41°3306''')<ref name="Simbad for A"/> is a [[triple star system]], estimated to be 11.2 billion years old (more than 80% of the age of the [[universe]]),<ref name="SP-20150127" /> approximately {{convert|119|ly|pc}} away from [[Earth]] in the [[constellation]] [[Lyra (constellation)|Lyra]]. On 27 January 2015, the [[Kepler (spacecraft)|''Kepler'' spacecraft]] is reported to have confirmed the detection of five sub-Earth-sized [[Rocky planet|rocky]] [[exoplanets]] orbiting the main star. The star is a [[K-type main sequence star]].<ref name="NASA-20150128"/><ref name="AP-20150127"/><ref name="UT-20150127"/><ref name="SP-20150127"/><ref name="EX-20150127"/> All of the planets are far too close to their star to harbour life forms.<ref name="NASA-20150128" />
-
-==Discovery==
-Preliminary results of the planetary system around Kepler-444 were first announced at the second [[Kepler space telescope|Kepler Science Conference]] in 2013. At that conference, the star was known as KOI-3158.<ref name="CAL-201311"/>
-
-==Characteristics==
-The star, Kepler-444, is approximately 11.2 billion years old, whereas the [[Sun]] is only 4.6 billion years old. The age is that of Kepler-444 A, an [[Main sequence|orange main sequence star]] of spectral type K0.<ref name="SL-20140128"/> Despite this great age, it is in middle of its main-sequence lifespan, much like the Sun.
-
-The original research on Kepler-444 was published in ''[[The Astrophysical Journal]]'' on 27 January 2015 under the title "An ancient extrasolar system with five sub-Earth-size planets" by a team of 40 authors, the abstract reads as follows:<ref name="Campante2015"/>
-
-<blockquote>The chemical composition of stars hosting small exoplanets (with radii less than four Earth radii) appears to be more diverse than that of [[Gas giant|gas-giant hosts]], which tend to be [[Metallicity|metal-rich]]. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were more scarce. We report Kepler spacecraft observations of Kepler-444, a metal-poor Sun-like star from the old population of the [[Thick disk|Galactic thick disk]] and the host to a compact system of five transiting planets with sizes between those of Mercury and Venus. We validate this system as a true five-planet system orbiting the target star and provide a detailed characterization of its planetary and orbital parameters based on an analysis of the [[transit photometry]]. Kepler-444 is the densest star with detected solar-like oscillations. We use [[asteroseismology]] to directly measure a precise age of 11.2+/-1.0 Gyr for the host star, indicating that Kepler-444 formed when the Universe was less than 20% of its current age and making it the oldest known system of [[Terrestrial planet|terrestrial-size planets]]. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, leaving open the possibility for the existence of ancient life in the [[Galaxy]]. The age of Kepler-444 not only suggests that thick-disk stars were among the hosts to the first Galactic planets, but may also help to pinpoint the beginning of the era of [[planet formation]]." The star is believed to have 2 M dwarfs in orbit around it with the fainter companion 1.8 arc-seconds from the main star.
-</blockquote>
-
-==Stellar system==
-The Kepler-444 system consists of the planet hosting primary and a pair of M-dwarf stars. The M-dwarfs orbit each other at a distance of less than 0.3 [[Astronomical unit|AU]] while the pair orbits the primary in a highly [[Orbital eccentricity|eccentric]] 324-year orbit. The pair comes within 23.55 AU of the primary potentially truncating the protoplanetary disk from which the planets formed at 8 AU. This would have depleted the availability of solid material to form the observed planets.<ref name="Zhang2023"/>
-
-Previous stellar orbit solution was ever more extreme, period was shorter (211 years) and eccentricity was much larger (e=0.865), moving periastron to 5 AU, severely reducing the estimated protoplanetary disk size to 1–2 AU and its estimated mass from 600 to 4 Earth masses.<ref name="Dupuy2016"/>
-
-==Planetary system==
-All five rocky exoplanets (Kepler-444b; Kepler-444c; Kepler-444d; Kepler-444e; Kepler-444f) are confirmed,<ref name="EX-20150127" /> smaller than the size of [[Venus]] (but bigger than [[Mercury (planet)|Mercury]]) and each of the exoplanets completes an orbit around the host star in less than 10 days.<ref name="NASA-20150128" /><ref name="SP-20150127" /> Thus, the planetary system is very compact, as even the furthest known planet, Kepler-444f, still orbits closer to the star than Mercury is to the [[Sun]].<ref name="SL-20140128" /> According to NASA, no life as we know it could exist on these hot exoplanets, due to their close orbital distances to the host star.<ref name="NASA-20150128" /> To keep the known planetary system stable, no additional giant planets can be located within 5.5 [[astronomical unit|AU]] of the parent star.<ref>{{citation|arxiv=1702.07714|title=Effects of Unseen Additional Planetary Perturbers on Compact Extrasolar Planetary Systems|year=2017|doi=10.1093/mnras/stx461|last1=Becker|first1=Juliette C.|last2=Adams|first2=Fred C.|journal=Monthly Notices of the Royal Astronomical Society|volume=468|issue=1|pages=549–563|bibcode=2017MNRAS.468..549B|s2cid=119325005}}</ref>
-
-Moreover, the system is pervaded by high-order resonance chain: period ratios are 4:5, 3:4, 4:5, 4:5. This tight chain is unperturbed and very likely continues farther from Kepler-444A.
-{{OrbitboxPlanet begin
-| table_ref = <ref name="EX-20150127" /><ref name="Mills2017"/>
-}}
-{{OrbitboxPlanet
-| exoplanet = b
-| mass_earth =
-| semimajor = 0.04178
-| period = {{val|3.600105|0.000031|0.000037}}
-| eccentricity = 0.16
-| inclination = 88
-| radius_earth = 0.406{{±|0.013}}
-}}
-{{OrbitboxPlanet
-| exoplanet = c
-| mass_earth =
-| semimajor = 0.04881
-| period = 4.545876{{±|0.000031}}
-| eccentricity = 0.31
-| inclination = 88.2
-| radius_earth = 0.521{{±|0.017}}
-}}
-{{OrbitboxPlanet
-| exoplanet = d
-| mass_earth = {{val|0.036|0.065|0.020}}
-| semimajor = 0.06
-| period = {{val|6.189437|0.000053|0.000037}}
-| eccentricity = 0.18
-| inclination = 88.16
-| radius_earth = 0.54{{±|0.017}}
-}}
-{{OrbitboxPlanet
-| exoplanet = e
-| mass_earth = {{val|0.034|0.059|0.019}}
-| semimajor = 0.0696
-| period = {{val|7.743467|0.00006|0.0001}}
-| eccentricity = 0.1
-| inclination = 89.13
-| radius_earth = {{val|0.555|0.018|0.016}}
-}}
-{{OrbitboxPlanet
-| exoplanet = f
-| mass_earth =
-| semimajor = 0.0811
-| period = {{val|9.740501|0.000078|0.000026}}
-| eccentricity = 0.29
-| inclination = 87.96
-| radius_earth = 0.767{{±|0.025}}
-}}
-{{Orbitbox end}}
-<!---
-{{wide image|LombergA1024.jpg|600px|align-cap=center|The ''[[Kepler (spacecraft)|Kepler Space Telescope]]'' search volume, in the context of the [[Milky Way Galaxy]].}}
---->
-{{-}}
-
-==See also==
-* [[Kepler-80]] - most compact 5-planet system discovered so far
-* [[Lists of exoplanets|List of extrasolar planets]]
-* [[PSR B1620-26]] - an ancient planetary system in [[Messier 4]]
-
-==References==
-{{Reflist|refs=
-
-<ref name="Buldgen2019">{{cite journal | title=Revisiting Kepler-444. I. Seismic modeling and inversions of stellar structure | last1=Buldgen | first1=G. | last2=Farnir | first2=M. | last3=Pezzotti | first3=C. | last4=Eggenberger | first4=P. | last5=Salmon | first5=S. J. A. J. | last6=Montalban | first6=J. | last7=Ferguson | first7=J. W. | last8=Khan | first8=S. | last9=Bourrier | first9=V. | last10=Rendle | first10=B. M. | last11=Meynet | first11=G. | last12=Miglio | first12=A. | last13=Noels | first13=A. | display-authors=1 | journal=Astronomy & Astrophysics | volume=630 | at=A126 | year=2019 | arxiv=1907.10315 | bibcode=2019A&A...630A.126B | doi=10.1051/0004-6361/201936126 | s2cid=198229778 }}</ref>
-
-<ref name="Campante2015">{{cite journal | title=An Ancient Extrasolar System with Five Sub-Earth-size Planets | last1=Campante | first1=T. L. | last2=Barclay | first2=T. | last3=Swift | first3=J. J. | last4=Huber | first4=D. | last5=Adibekyan | first5=V. Zh. | last6=Cochran | first6=W. | last7=Burke | first7=C. J. | last8=Isaacson | first8=H. | last9=Quintana | first9=E. V. | last10=Davies | first10=G. R. | last11=Silva Aguirre | first11=V. | last12=Ragozzine | first12=D. | last13=Riddle | first13=R. | last14=Baranec | first14=C. | last15=Basu | first15=S. | last16=Chaplin | first16=W. J. | last17=Christensen-Dalsgaard | first17=J. | last18=Metcalfe | first18=T. S. | last19=Bedding | first19=T. R. | last20=Handberg | first20=R. | last21=Stello | first21=D. | last22=Brewer | first22=J. M. | last23=Hekker | first23=S. | last24=Karoff | first24=C. | last25=Kolbl | first25=R. | last26=Law | first26=N. M. | last27=Lundkvist | first27=M. | last28=Miglio | first28=A. | last29=Rowe | first29=J. F. | last30=Santos | first30=N. C. | last31=Van Laerhoven | first31=C. | last32=Arentoft | first32=T. | last33=Elsworth | first33=Y. P. | last34=Fischer | first34=D. A. | last35=Kawaler | first35=S. D. | last36=Kjeldsen | first36=H. | last37=Lund | first37=M. N. | last38=Marcy | first38=G. W. | last39=Sousa | first39=S. G. | last40=Sozzetti | first40=A. | last41=White | first41=T. R. | display-authors=1 | journal=The Astrophysical Journal | volume=799 | issue=2 | at=170 | year=2015 | arxiv=1501.06227 | bibcode=2015ApJ...799..170C | bibcode-access=free | doi=10.1088/0004-637X/799/2/170 | doi-access=free }}</ref>
-
-<ref name="Dupuy2016">{{cite journal | title=Orbital Architectures of Planet-Hosting Binaries. I. Forming Five Small Planets in the Truncated Disk of Kepler-444A | last1=Dupuy | first1=Trent J. | last2=Kratter | first2=Kaitlin M. | last3=Kraus | first3=Adam L. | last4=Isaacson | first4=Howard | last5=Mann | first5=Andrew W. | last6=Ireland | first6=Michael J. | last7=Howard | first7=Andrew W. | last8=Huber | first8=Daniel | display-authors=1 | journal=The Astrophysical Journal | volume=817 | issue=1 | at=80 | year=2016 | arxiv=1512.03428 | bibcode=2016ApJ...817...80D | bibcode-access=free | doi=10.3847/0004-637X/817/1/80 | doi-access=free }}</ref>
-
-<ref name="Gaia DR2">{{Cite Gaia DR2|2101486923385239808}}</ref>
-
-<ref name="Mazeh2015">{{cite journal | title=Photometric Amplitude Distribution of Stellar Rotation of KOIs—Indication for Spin-Orbit Alignment of Cool Stars and High Obliquity for Hot Stars | last1=Mazeh | first1=Tsevi | last2=Perets | first2=Hagai B. | last3=McQuillan | first3=Amy | last4=Goldstein | first4=Eyal S. | display-authors=1 | journal=The Astrophysical Journal | volume=801 | issue=1 | at=3 | year=2015 | arxiv=1501.01288 | bibcode=2015ApJ...801....3M | bibcode-access=free | doi=10.1088/0004-637X/801/1/3 | doi-access=free }}</ref>
-
-<ref name="Mills2017">{{cite journal | title=Mass, Density, and Formation Constraints in the Compact, Sub-Earth Kepler-444 System including Two Mars-mass Planets | last1=Mills | first1=Sean M. | last2=Fabrycky | first2=Daniel C. | journal=The Astrophysical Journal Letters | volume=838 | issue=1 | at=L11 | year=2017 | arxiv=1703.03417 | bibcode=2017ApJ...838L..11M | bibcode-access=free | doi=10.3847/2041-8213/aa6543 | doi-access=free }}</ref>
-
-<ref name="Simbad for A">{{cite simbad | title=BD+41 3306 | access-date=2020-08-20 }}</ref>
-
-<ref name="Simbad for B">{{cite simbad | title=BD+41 3306B | access-date=2020-08-20 }}</ref>
-
-<ref name="NASA-20150128">{{cite web |last=Johnson |first=Michele |title=Astronomers Discover Ancient System with Five Small Planets |url=http://www.nasa.gov/ames/kepler/astronomers-discover-ancient-system-with-five-small-planets |date=28 January 2015 |work=[[NASA]] |access-date=29 January 2015}}</ref>
-
-<ref name="AP-20150127">{{cite news |last=Dunn |first=Marcia |title=Astronomers find solar system more than double ours in age |url=http://apnews.excite.com/article/20150127/us-sci--old_solar_system-56b7594709.html |date=27 January 2015 |work=[[AP News]] |access-date=27 January 2015}}</ref>
-
-<ref name="UT-20150127">{{cite web |last1=Atkinson |first1=Nancy |title=Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere |url=http://www.universetoday.com/118510/oldest-planetary-system-discovered-improving-the-chances-for-intelligent-life-everywhere/ |date=27 January 2015 |work=[[Universe Today]] |access-date=27 January 2015}}</ref>
-
-<ref name="SP-20150127">{{cite web |last=Wall |first=Mike |title=Found! 5 Ancient Alien Planets Nearly As Old As the Universe |url=http://www.space.com/28386-ancient-alien-planets-discovery-kepler-444.html |date=27 January 2015 |work=[[Space.com]] |access-date=27 January 2015}}</ref>
-
-<ref name="EX-20150127">{{cite encyclopedia |author=Staff |title=Exoplanet Catalog |url=http://exoplanet.eu/catalog/ |date=27 January 2015 |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |access-date=27 January 2015}}</ref>
-
-<ref name="CAL-201311">{{cite web |author=Staff |title=Second Kepler Science Conference - NASA Ames Research Center, Mountain View, CA - Nov. 4-8, 2013 - Agenda |url=http://nexsci.caltech.edu/conferences/KeplerII/agenda.shtml |date=8 November 2013 |work=[[Caltech]] |access-date=28 January 2014}}</ref>
-
-<ref name="SL-20140128">{{cite news |last=Phil |first=Plait |author-link=Phil Plait |title=Astronomers Find Ancient Earth-Sized Planets in Our Galactic Backyard |url=http://www.slate.com/blogs/bad_astronomy/2015/01/27/exoplanets_five_extremely_old_planets_found_around_kepler_444.html |date=28 January 2015 |work=[[Slate (magazine)|Slate]] |access-date=28 January 2015}}</ref> is more than 80% of the [[age of the universe]].
-
-<ref name=wilson1962>{{cite journal |bibcode=1962ApJ...136..793W |title=Relationship Between Colors and Spectra of Late Main-Sequence Stars |last1=Wilson |first1=O. C. |journal=The Astrophysical Journal |year=1962 |volume=136 |page=793 |doi=10.1086/147437 }}</ref>
-
-<ref name=ducati2002>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati, J. R.|year=2002}}</ref</ref>>
-<!--
-<ref name=Stalport2022>{{cite journal | arxiv=2209.06810 | doi=10.1051/0004-6361/202243971 | bibcode=2022A&A...667A.128S | title=Global dynamics and architecture of the Kepler-444 system | year=2022 | last1=Stalport | first1=M. | last2=Matthews | first2=E. C. | last3=Bourrier | first3=V. | last4=Leleu | first4=A. | last5=Delisle | first5=J.-B. | last6=Udry | first6=S. | journal=Astronomy & Astrophysics | volume=667 | pages=A128 | s2cid=252222215 }}</ref>
--->
-<ref name=Zhang2023>{{cite journal |doi=10.3847/1538-3881/aca88c |title=The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-planet Host System Kepler-444 |year=2023 |last1=Zhang |first1=Zhoujian |last2=Bowler |first2=Brendan P. |last3=Dupuy |first3=Trent J. |last4=Brandt |first4=Timothy D. |last5=Brandt |first5=G. Mirek |last6=Cochran |first6=William D. |last7=Endl |first7=Michael |last8=MacQueen |first8=Phillip J. |last9=Kratter |first9=Kaitlin M. |last10=Isaacson |first10=Howard T. |last11=Franson |first11=Kyle |last12=Kraus |first12=Adam L. |last13=Morley |first13=Caroline V. |last14=Zhou |first14=Yifan |journal=The Astronomical Journal |volume=165 |issue=2 |page=73 |arxiv=2210.07252 |bibcode=2023AJ....165...73Z |s2cid=252907948 }}</ref>
-}}
-
-==External links==
-* [http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=KOI-3158 NASA – Kepler-444/KOI-3158] at [[NASA Exoplanet Archive|The NASA Exoplanet Archive]]
-* [http://exoplanet.eu/catalog/kepler-444_b/ NASA – Kepler-444'''b''']/[http://exoplanet.eu/catalog/kepler-444_c/ '''c''']/[http://exoplanet.eu/catalog/kepler-444_d/ '''d''']/[http://exoplanet.eu/catalog/kepler-444_e/ '''e''']/[http://exoplanet.eu/catalog/kepler-444_f/ '''f'''] at [[The Extrasolar Planets Encyclopaedia|Extrasolar Planets Encyclopaedia]]
-
-{{Stars of Lyra}}
-{{2015 in space}}
-{{Portal bar|Astronomy|Biology}}
-{{Sky|19|19|01.0|+|41|38|05|117}}
-
-[[Category:Lyra (constellation)]]
-[[Category:Planetary systems with five confirmed planets]]
-[[Category:K-type main-sequence stars]]
-[[Category:Kepler objects of interest|3158]]
-[[Category:Planetary transit variables]]
-[[Category:2MASS objects|J19190052+4138043]]
-[[Category:Hipparcos objects|94931]]
-[[Category:Durchmusterung objects]]
-[[Category:M-type main-sequence stars]]
-[[Category:Triple star systems]]
-[[Category:TIC objects]]
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Lines removed in edit (removed_lines ) | [
0 => '{{Use dmy dates|date=January 2015}}',
1 => '{{Short description|Triple star system in the constellation of Lyra}}',
2 => '{{Starbox begin',
3 => '| name = Kepler-444',
4 => '}}',
5 => '{{Starbox observe',
6 => '| epoch = J2000',
7 => '| equinox = 2000',
8 => '| constell = [[Lyra (constellation)|Lyra]]',
9 => '| ra = {{RA|19|19|00.5488}}<ref name="Gaia DR2"/>',
10 => '| dec = {{DEC|+41|38|04.5816}}<ref name="Gaia DR2"/>',
11 => '| appmag_v =8.86<ref name=ducati2002/>',
12 => '}}',
13 => '{{Starbox character',
14 => '| class = K0V<ref name=wilson1962/>',
15 => '}}',
16 => '{{Starbox astrometry',
17 => '| radial_v = {{val|-123.05|0.17}}<ref name="Dupuy2016"/>',
18 => '| prop_mo_ra = {{val|94.682|0.055}}<ref name="Gaia DR2"/>',
19 => '| prop_mo_dec = {{val|−632.202|0.051}}<ref name="Gaia DR2"/>',
20 => '| parallax = 27.4137',
21 => '| p_error = 0.0295',
22 => '| parallax_footnote = <ref name="Gaia DR2"/>',
23 => '| absmag_v =',
24 => '}}',
25 => '{{Starbox orbit',
26 => '| reference = <ref name=Zhang2023/>',
27 => '| primary = A',
28 => '| name = BC',
29 => '| axis_unitless = {{val|52.2|+3.3|−2.7}} AU',
30 => '| eccentricity = {{val|0.55|+0.05|−0.05}}',
31 => '| inclination = {{val|85.4|+0.3|−0.4}}',
32 => '| node = {{val|250.7|+0.2|−0.2}}',
33 => '| periarg = {{val|227.3|+6.5|−5.2}}',
34 => '| period = {{val|324|+31|−25}}',
35 => '| periastron = JD {{val|2537060|+10881|−8533}}',
36 => '}}',
37 => '{{Starbox detail',
38 => '| component1 = A',
39 => '| mass = {{val|0.754|0.030}}<ref name="Buldgen2019"/>',
40 => '| radius = {{val|0.753|0.010}}<ref name="Buldgen2019"/>',
41 => '| luminosity_bolometric = ',
42 => '| temperature = {{val|5046|74.0}}<ref name="Campante2015"/>',
43 => '| gravity = {{val|4.595|0.060}}<ref name="Campante2015"/>',
44 => '| metal_fe = {{val|−0.55|0.07}}<ref name="Campante2015"/>',
45 => '| rotation = {{val|49.40|6.04|u=days}}<ref name="Mazeh2015"/>',
46 => '| age_gyr = {{val|11.00|0.8}}<ref name="Buldgen2019"/>',
47 => '}}',
48 => '{{Starbox detail |no_heading=y',
49 => '| component1 = B',
50 => '| mass = {{val|0.307|0.009|0.008}}<ref name=Zhang2023/>',
51 => '| temperature = {{val|3,464|200|fmt=commas}}<ref name="Campante2015"/>',
52 => '| gravity = {{val|5.0|0.2}}<ref name="Campante2015"/>',
53 => '| component2 = C',
54 => '| mass2 = {{val|0.296|0.008}}<ref name=Zhang2023/>',
55 => '| temperature2 = 3,500 - 4,000<ref name="Campante2015"/>',
56 => '| gravity2 = ~5<ref name="Campante2015"/>',
57 => '}}',
58 => '{{Starbox catalog',
59 => '| names = {{odlist | 2MASS=J19190052+4138043 | BD=+41°3306 | KIC=6278762 | KOI=3158 | WDS=J19190+4138 }}',
60 => '| component1 = Kepler-444A',
61 => '| names1 = {{odlist | 2MASS=J19190052+4138043 | Gaia DR2=2101486923385239808 | HIP=94931 | LHS=3450 | TYC=3129-00329-1 }}<ref name="Simbad for A"/>',
62 => '| component2 = Kepler-444BC',
63 => '| names2 = {{odlist | Gaia DR2=2101486923382009472 }}<ref name="Simbad for B"/>',
64 => '}}',
65 => '{{Starbox reference',
66 => '| Simbad = KOI-3158',
67 => '| Simbad2 = KOI+3158B |sn2=B/C',
68 => '}}',
69 => '{{Starbox end}}',
70 => '',
71 => ''''Kepler-444''' (or '''KOI-3158''', '''KIC 6278762''', '''2MASS J19190052+4138043''', '''BD+41°3306''')<ref name="Simbad for A"/> is a [[triple star system]], estimated to be 11.2 billion years old (more than 80% of the age of the [[universe]]),<ref name="SP-20150127" /> approximately {{convert|119|ly|pc}} away from [[Earth]] in the [[constellation]] [[Lyra (constellation)|Lyra]]. On 27 January 2015, the [[Kepler (spacecraft)|''Kepler'' spacecraft]] is reported to have confirmed the detection of five sub-Earth-sized [[Rocky planet|rocky]] [[exoplanets]] orbiting the main star. The star is a [[K-type main sequence star]].<ref name="NASA-20150128"/><ref name="AP-20150127"/><ref name="UT-20150127"/><ref name="SP-20150127"/><ref name="EX-20150127"/> All of the planets are far too close to their star to harbour life forms.<ref name="NASA-20150128" />',
72 => '',
73 => '==Discovery==',
74 => 'Preliminary results of the planetary system around Kepler-444 were first announced at the second [[Kepler space telescope|Kepler Science Conference]] in 2013. At that conference, the star was known as KOI-3158.<ref name="CAL-201311"/>',
75 => '',
76 => '==Characteristics==',
77 => 'The star, Kepler-444, is approximately 11.2 billion years old, whereas the [[Sun]] is only 4.6 billion years old. The age is that of Kepler-444 A, an [[Main sequence|orange main sequence star]] of spectral type K0.<ref name="SL-20140128"/> Despite this great age, it is in middle of its main-sequence lifespan, much like the Sun.',
78 => '',
79 => 'The original research on Kepler-444 was published in ''[[The Astrophysical Journal]]'' on 27 January 2015 under the title "An ancient extrasolar system with five sub-Earth-size planets" by a team of 40 authors, the abstract reads as follows:<ref name="Campante2015"/>',
80 => '',
81 => '<blockquote>The chemical composition of stars hosting small exoplanets (with radii less than four Earth radii) appears to be more diverse than that of [[Gas giant|gas-giant hosts]], which tend to be [[Metallicity|metal-rich]]. This implies that small, including Earth-size, planets may have readily formed at earlier epochs in the Universe's history when metals were more scarce. We report Kepler spacecraft observations of Kepler-444, a metal-poor Sun-like star from the old population of the [[Thick disk|Galactic thick disk]] and the host to a compact system of five transiting planets with sizes between those of Mercury and Venus. We validate this system as a true five-planet system orbiting the target star and provide a detailed characterization of its planetary and orbital parameters based on an analysis of the [[transit photometry]]. Kepler-444 is the densest star with detected solar-like oscillations. We use [[asteroseismology]] to directly measure a precise age of 11.2+/-1.0 Gyr for the host star, indicating that Kepler-444 formed when the Universe was less than 20% of its current age and making it the oldest known system of [[Terrestrial planet|terrestrial-size planets]]. We thus show that Earth-size planets have formed throughout most of the Universe's 13.8-billion-year history, leaving open the possibility for the existence of ancient life in the [[Galaxy]]. The age of Kepler-444 not only suggests that thick-disk stars were among the hosts to the first Galactic planets, but may also help to pinpoint the beginning of the era of [[planet formation]]." The star is believed to have 2 M dwarfs in orbit around it with the fainter companion 1.8 arc-seconds from the main star.',
82 => '</blockquote>',
83 => '',
84 => '==Stellar system==',
85 => 'The Kepler-444 system consists of the planet hosting primary and a pair of M-dwarf stars. The M-dwarfs orbit each other at a distance of less than 0.3 [[Astronomical unit|AU]] while the pair orbits the primary in a highly [[Orbital eccentricity|eccentric]] 324-year orbit. The pair comes within 23.55 AU of the primary potentially truncating the protoplanetary disk from which the planets formed at 8 AU. This would have depleted the availability of solid material to form the observed planets.<ref name="Zhang2023"/>',
86 => '',
87 => 'Previous stellar orbit solution was ever more extreme, period was shorter (211 years) and eccentricity was much larger (e=0.865), moving periastron to 5 AU, severely reducing the estimated protoplanetary disk size to 1–2 AU and its estimated mass from 600 to 4 Earth masses.<ref name="Dupuy2016"/>',
88 => '',
89 => '==Planetary system==',
90 => 'All five rocky exoplanets (Kepler-444b; Kepler-444c; Kepler-444d; Kepler-444e; Kepler-444f) are confirmed,<ref name="EX-20150127" /> smaller than the size of [[Venus]] (but bigger than [[Mercury (planet)|Mercury]]) and each of the exoplanets completes an orbit around the host star in less than 10 days.<ref name="NASA-20150128" /><ref name="SP-20150127" /> Thus, the planetary system is very compact, as even the furthest known planet, Kepler-444f, still orbits closer to the star than Mercury is to the [[Sun]].<ref name="SL-20140128" /> According to NASA, no life as we know it could exist on these hot exoplanets, due to their close orbital distances to the host star.<ref name="NASA-20150128" /> To keep the known planetary system stable, no additional giant planets can be located within 5.5 [[astronomical unit|AU]] of the parent star.<ref>{{citation|arxiv=1702.07714|title=Effects of Unseen Additional Planetary Perturbers on Compact Extrasolar Planetary Systems|year=2017|doi=10.1093/mnras/stx461|last1=Becker|first1=Juliette C.|last2=Adams|first2=Fred C.|journal=Monthly Notices of the Royal Astronomical Society|volume=468|issue=1|pages=549–563|bibcode=2017MNRAS.468..549B|s2cid=119325005}}</ref>',
91 => '',
92 => 'Moreover, the system is pervaded by high-order resonance chain: period ratios are 4:5, 3:4, 4:5, 4:5. This tight chain is unperturbed and very likely continues farther from Kepler-444A.',
93 => '{{OrbitboxPlanet begin',
94 => '| table_ref = <ref name="EX-20150127" /><ref name="Mills2017"/>',
95 => '}}',
96 => '{{OrbitboxPlanet',
97 => '| exoplanet = b',
98 => '| mass_earth = ',
99 => '| semimajor = 0.04178',
100 => '| period = {{val|3.600105|0.000031|0.000037}}',
101 => '| eccentricity = 0.16',
102 => '| inclination = 88 ',
103 => '| radius_earth = 0.406{{±|0.013}}',
104 => '}}',
105 => '{{OrbitboxPlanet',
106 => '| exoplanet = c',
107 => '| mass_earth = ',
108 => '| semimajor = 0.04881',
109 => '| period = 4.545876{{±|0.000031}}',
110 => '| eccentricity = 0.31',
111 => '| inclination = 88.2',
112 => '| radius_earth = 0.521{{±|0.017}}',
113 => '}}',
114 => '{{OrbitboxPlanet',
115 => '| exoplanet = d',
116 => '| mass_earth = {{val|0.036|0.065|0.020}}',
117 => '| semimajor = 0.06',
118 => '| period = {{val|6.189437|0.000053|0.000037}}',
119 => '| eccentricity = 0.18',
120 => '| inclination = 88.16',
121 => '| radius_earth = 0.54{{±|0.017}}',
122 => '}}',
123 => '{{OrbitboxPlanet',
124 => '| exoplanet = e',
125 => '| mass_earth = {{val|0.034|0.059|0.019}}',
126 => '| semimajor = 0.0696',
127 => '| period = {{val|7.743467|0.00006|0.0001}}',
128 => '| eccentricity = 0.1',
129 => '| inclination = 89.13',
130 => '| radius_earth = {{val|0.555|0.018|0.016}}',
131 => '}}',
132 => '{{OrbitboxPlanet',
133 => '| exoplanet = f',
134 => '| mass_earth = ',
135 => '| semimajor = 0.0811',
136 => '| period = {{val|9.740501|0.000078|0.000026}}',
137 => '| eccentricity = 0.29',
138 => '| inclination = 87.96',
139 => '| radius_earth = 0.767{{±|0.025}}',
140 => '}}',
141 => '{{Orbitbox end}}',
142 => '<!---',
143 => '{{wide image|LombergA1024.jpg|600px|align-cap=center|The ''[[Kepler (spacecraft)|Kepler Space Telescope]]'' search volume, in the context of the [[Milky Way Galaxy]].}}',
144 => '--->',
145 => '{{-}}',
146 => '',
147 => '==See also==',
148 => '* [[Kepler-80]] - most compact 5-planet system discovered so far',
149 => '* [[Lists of exoplanets|List of extrasolar planets]]',
150 => '* [[PSR B1620-26]] - an ancient planetary system in [[Messier 4]]',
151 => '',
152 => '==References==',
153 => '{{Reflist|refs=',
154 => '',
155 => '<ref name="Buldgen2019">{{cite journal | title=Revisiting Kepler-444. I. Seismic modeling and inversions of stellar structure | last1=Buldgen | first1=G. | last2=Farnir | first2=M. | last3=Pezzotti | first3=C. | last4=Eggenberger | first4=P. | last5=Salmon | first5=S. J. A. J. | last6=Montalban | first6=J. | last7=Ferguson | first7=J. W. | last8=Khan | first8=S. | last9=Bourrier | first9=V. | last10=Rendle | first10=B. M. | last11=Meynet | first11=G. | last12=Miglio | first12=A. | last13=Noels | first13=A. | display-authors=1 | journal=Astronomy & Astrophysics | volume=630 | at=A126 | year=2019 | arxiv=1907.10315 | bibcode=2019A&A...630A.126B | doi=10.1051/0004-6361/201936126 | s2cid=198229778 }}</ref>',
156 => '',
157 => '<ref name="Campante2015">{{cite journal | title=An Ancient Extrasolar System with Five Sub-Earth-size Planets | last1=Campante | first1=T. L. | last2=Barclay | first2=T. | last3=Swift | first3=J. J. | last4=Huber | first4=D. | last5=Adibekyan | first5=V. Zh. | last6=Cochran | first6=W. | last7=Burke | first7=C. J. | last8=Isaacson | first8=H. | last9=Quintana | first9=E. V. | last10=Davies | first10=G. R. | last11=Silva Aguirre | first11=V. | last12=Ragozzine | first12=D. | last13=Riddle | first13=R. | last14=Baranec | first14=C. | last15=Basu | first15=S. | last16=Chaplin | first16=W. J. | last17=Christensen-Dalsgaard | first17=J. | last18=Metcalfe | first18=T. S. | last19=Bedding | first19=T. R. | last20=Handberg | first20=R. | last21=Stello | first21=D. | last22=Brewer | first22=J. M. | last23=Hekker | first23=S. | last24=Karoff | first24=C. | last25=Kolbl | first25=R. | last26=Law | first26=N. M. | last27=Lundkvist | first27=M. | last28=Miglio | first28=A. | last29=Rowe | first29=J. F. | last30=Santos | first30=N. C. | last31=Van Laerhoven | first31=C. | last32=Arentoft | first32=T. | last33=Elsworth | first33=Y. P. | last34=Fischer | first34=D. A. | last35=Kawaler | first35=S. D. | last36=Kjeldsen | first36=H. | last37=Lund | first37=M. N. | last38=Marcy | first38=G. W. | last39=Sousa | first39=S. G. | last40=Sozzetti | first40=A. | last41=White | first41=T. R. | display-authors=1 | journal=The Astrophysical Journal | volume=799 | issue=2 | at=170 | year=2015 | arxiv=1501.06227 | bibcode=2015ApJ...799..170C | bibcode-access=free | doi=10.1088/0004-637X/799/2/170 | doi-access=free }}</ref>',
158 => ' ',
159 => '<ref name="Dupuy2016">{{cite journal | title=Orbital Architectures of Planet-Hosting Binaries. I. Forming Five Small Planets in the Truncated Disk of Kepler-444A | last1=Dupuy | first1=Trent J. | last2=Kratter | first2=Kaitlin M. | last3=Kraus | first3=Adam L. | last4=Isaacson | first4=Howard | last5=Mann | first5=Andrew W. | last6=Ireland | first6=Michael J. | last7=Howard | first7=Andrew W. | last8=Huber | first8=Daniel | display-authors=1 | journal=The Astrophysical Journal | volume=817 | issue=1 | at=80 | year=2016 | arxiv=1512.03428 | bibcode=2016ApJ...817...80D | bibcode-access=free | doi=10.3847/0004-637X/817/1/80 | doi-access=free }}</ref>',
160 => '',
161 => '<ref name="Gaia DR2">{{Cite Gaia DR2|2101486923385239808}}</ref>',
162 => '',
163 => '<ref name="Mazeh2015">{{cite journal | title=Photometric Amplitude Distribution of Stellar Rotation of KOIs—Indication for Spin-Orbit Alignment of Cool Stars and High Obliquity for Hot Stars | last1=Mazeh | first1=Tsevi | last2=Perets | first2=Hagai B. | last3=McQuillan | first3=Amy | last4=Goldstein | first4=Eyal S. | display-authors=1 | journal=The Astrophysical Journal | volume=801 | issue=1 | at=3 | year=2015 | arxiv=1501.01288 | bibcode=2015ApJ...801....3M | bibcode-access=free | doi=10.1088/0004-637X/801/1/3 | doi-access=free }}</ref>',
164 => '',
165 => '<ref name="Mills2017">{{cite journal | title=Mass, Density, and Formation Constraints in the Compact, Sub-Earth Kepler-444 System including Two Mars-mass Planets | last1=Mills | first1=Sean M. | last2=Fabrycky | first2=Daniel C. | journal=The Astrophysical Journal Letters | volume=838 | issue=1 | at=L11 | year=2017 | arxiv=1703.03417 | bibcode=2017ApJ...838L..11M | bibcode-access=free | doi=10.3847/2041-8213/aa6543 | doi-access=free }}</ref>',
166 => '',
167 => '<ref name="Simbad for A">{{cite simbad | title=BD+41 3306 | access-date=2020-08-20 }}</ref>',
168 => '',
169 => '<ref name="Simbad for B">{{cite simbad | title=BD+41 3306B | access-date=2020-08-20 }}</ref>',
170 => '',
171 => '<ref name="NASA-20150128">{{cite web |last=Johnson |first=Michele |title=Astronomers Discover Ancient System with Five Small Planets |url=http://www.nasa.gov/ames/kepler/astronomers-discover-ancient-system-with-five-small-planets |date=28 January 2015 |work=[[NASA]] |access-date=29 January 2015}}</ref>',
172 => '',
173 => '<ref name="AP-20150127">{{cite news |last=Dunn |first=Marcia |title=Astronomers find solar system more than double ours in age |url=http://apnews.excite.com/article/20150127/us-sci--old_solar_system-56b7594709.html |date=27 January 2015 |work=[[AP News]] |access-date=27 January 2015}}</ref>',
174 => '',
175 => '<ref name="UT-20150127">{{cite web |last1=Atkinson |first1=Nancy |title=Oldest Planetary System Discovered, Improving the Chances for Intelligent Life Everywhere |url=http://www.universetoday.com/118510/oldest-planetary-system-discovered-improving-the-chances-for-intelligent-life-everywhere/ |date=27 January 2015 |work=[[Universe Today]] |access-date=27 January 2015}}</ref>',
176 => '',
177 => '<ref name="SP-20150127">{{cite web |last=Wall |first=Mike |title=Found! 5 Ancient Alien Planets Nearly As Old As the Universe |url=http://www.space.com/28386-ancient-alien-planets-discovery-kepler-444.html |date=27 January 2015 |work=[[Space.com]] |access-date=27 January 2015}}</ref>',
178 => '',
179 => '<ref name="EX-20150127">{{cite encyclopedia |author=Staff |title=Exoplanet Catalog |url=http://exoplanet.eu/catalog/ |date=27 January 2015 |encyclopedia=[[Extrasolar Planets Encyclopaedia]] |access-date=27 January 2015}}</ref>',
180 => '',
181 => '<ref name="CAL-201311">{{cite web |author=Staff |title=Second Kepler Science Conference - NASA Ames Research Center, Mountain View, CA - Nov. 4-8, 2013 - Agenda |url=http://nexsci.caltech.edu/conferences/KeplerII/agenda.shtml |date=8 November 2013 |work=[[Caltech]] |access-date=28 January 2014}}</ref>',
182 => '',
183 => '<ref name="SL-20140128">{{cite news |last=Phil |first=Plait |author-link=Phil Plait |title=Astronomers Find Ancient Earth-Sized Planets in Our Galactic Backyard |url=http://www.slate.com/blogs/bad_astronomy/2015/01/27/exoplanets_five_extremely_old_planets_found_around_kepler_444.html |date=28 January 2015 |work=[[Slate (magazine)|Slate]] |access-date=28 January 2015}}</ref> is more than 80% of the [[age of the universe]].',
184 => '',
185 => '<ref name=wilson1962>{{cite journal |bibcode=1962ApJ...136..793W |title=Relationship Between Colors and Spectra of Late Main-Sequence Stars |last1=Wilson |first1=O. C. |journal=The Astrophysical Journal |year=1962 |volume=136 |page=793 |doi=10.1086/147437 }}</ref>',
186 => '',
187 => '<ref name=ducati2002>{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|author1=Ducati, J. R.|year=2002}}</ref</ref>>',
188 => '<!--',
189 => '<ref name=Stalport2022>{{cite journal | arxiv=2209.06810 | doi=10.1051/0004-6361/202243971 | bibcode=2022A&A...667A.128S | title=Global dynamics and architecture of the Kepler-444 system | year=2022 | last1=Stalport | first1=M. | last2=Matthews | first2=E. C. | last3=Bourrier | first3=V. | last4=Leleu | first4=A. | last5=Delisle | first5=J.-B. | last6=Udry | first6=S. | journal=Astronomy & Astrophysics | volume=667 | pages=A128 | s2cid=252222215 }}</ref>',
190 => '-->',
191 => '<ref name=Zhang2023>{{cite journal |doi=10.3847/1538-3881/aca88c |title=The McDonald Accelerating Stars Survey: Architecture of the Ancient Five-planet Host System Kepler-444 |year=2023 |last1=Zhang |first1=Zhoujian |last2=Bowler |first2=Brendan P. |last3=Dupuy |first3=Trent J. |last4=Brandt |first4=Timothy D. |last5=Brandt |first5=G. Mirek |last6=Cochran |first6=William D. |last7=Endl |first7=Michael |last8=MacQueen |first8=Phillip J. |last9=Kratter |first9=Kaitlin M. |last10=Isaacson |first10=Howard T. |last11=Franson |first11=Kyle |last12=Kraus |first12=Adam L. |last13=Morley |first13=Caroline V. |last14=Zhou |first14=Yifan |journal=The Astronomical Journal |volume=165 |issue=2 |page=73 |arxiv=2210.07252 |bibcode=2023AJ....165...73Z |s2cid=252907948 }}</ref>',
192 => '}}',
193 => '',
194 => '==External links==',
195 => '* [http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?objname=KOI-3158 NASA – Kepler-444/KOI-3158] at [[NASA Exoplanet Archive|The NASA Exoplanet Archive]]',
196 => '* [http://exoplanet.eu/catalog/kepler-444_b/ NASA – Kepler-444'''b''']/[http://exoplanet.eu/catalog/kepler-444_c/ '''c''']/[http://exoplanet.eu/catalog/kepler-444_d/ '''d''']/[http://exoplanet.eu/catalog/kepler-444_e/ '''e''']/[http://exoplanet.eu/catalog/kepler-444_f/ '''f'''] at [[The Extrasolar Planets Encyclopaedia|Extrasolar Planets Encyclopaedia]]',
197 => '',
198 => '{{Stars of Lyra}}',
199 => '{{2015 in space}}',
200 => '{{Portal bar|Astronomy|Biology}}',
201 => '{{Sky|19|19|01.0|+|41|38|05|117}}',
202 => '',
203 => '[[Category:Lyra (constellation)]]',
204 => '[[Category:Planetary systems with five confirmed planets]]',
205 => '[[Category:K-type main-sequence stars]]',
206 => '[[Category:Kepler objects of interest|3158]]',
207 => '[[Category:Planetary transit variables]]',
208 => '[[Category:2MASS objects|J19190052+4138043]]',
209 => '[[Category:Hipparcos objects|94931]]',
210 => '[[Category:Durchmusterung objects]]',
211 => '[[Category:M-type main-sequence stars]]',
212 => '[[Category:Triple star systems]]',
213 => '[[Category:TIC objects]]'
] |
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35 => 'https://arxiv.org/abs/1907.10315',
36 => 'https://arxiv.org/abs/2210.07252',
37 => 'https://doi.org/10.1051%2F0004-6361%2F201833051',
38 => 'https://doi.org/10.1051%2F0004-6361%2F201936126',
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41 => 'https://doi.org/10.1088%2F0004-637X%2F801%2F1%2F3',
42 => 'https://doi.org/10.1093%2Fmnras%2Fstx461',
43 => 'https://doi.org/10.3847%2F0004-637X%2F817%2F1%2F80',
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48 => 'https://api.semanticscholar.org/CorpusID:252907948'
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