Kepler-31#Planetary system
{{short description|Star in the constellation Cygnus}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000
| constell = Cygnus
| appmag_v = 14.0{{citation
| title=Kepler-31b
| publisher=NASA Ames Research Center
| url=http://kepler.nasa.gov/Mission/discoveries/kepler30b/
| archive-url=https://web.archive.org/web/20120503111252/http://kepler.nasa.gov/Mission/discoveries/kepler30b/
| url-status=dead
| archive-date=2012-05-03
| access-date=2011-12-06 }}
}}
{{Starbox character
| class = G5{{citation
|first1=Jean
|last1=Schneider
|title=Star: Kepler-23
|url=http://exoplanet.eu/star.php?st=Kepler-31
|access-date=2011-12-06
|url-status=dead
|archive-url=https://web.archive.org/web/20120505101439/http://exoplanet.eu/star.php?st=Kepler-31
|encyclopedia=Extrasolar Planets Encyclopaedia
|archive-date=2012-05-05
}}
| appmag_1_passband =
| appmag_1 =
| appmag_2_passband =
| appmag_2 =
| appmag_3_passband =
| appmag_3 =
| appmag_4_passband =
| appmag_4 =
| appmag_5_passband =
| appmag_5 =
| r-i =
| v-r =
| b-v =
| u-b =
| variable =
}}
{{Starbox astrometry
| radial_v =
| prop_mo_ra = {{val|−1.007|(25)}}
| prop_mo_dec = {{val|−7.439|(23)}}
| parallax = 0.6013
| p_error = 0.0200
| absmag_v =
}}
{{Starbox detail
| mass = {{nowrap|1.21 ± 0.17}}
| luminosity = {{nowrap|0.79 ± 0.04}}
| habitable zone = {{nowrap|0.85-1.22}}
| temperature = {{nowrap|6340 ± 200}}
| metal_fe = {{nowrap|–0.076 ± 0.400}}
| radius = {{nowrap|1.22 ± 0.24}}
| rotational_velocity =
| age =
}}
{{Starbox catalog
| names = KOI-935, KIC 9347899, 2MASS J19360552+4551110, Gaia DR2 2128013019361703936
}}
{{Starbox reference
| Simbad = Kepler-31
| KIC = 9347899
}}
{{Starbox end}}
Kepler-31 is a star in the northern constellation of Cygnus, the swan. It is orbited by three known exoplanets. It is located at the celestial coordinates: Right Ascension {{RA|19|36|05.5270}}, Declination {{DEC|+45|51|11.108}}. With an apparent visual magnitude of 14.0, this star is too faint to be seen with the naked eye.
Planetary system
The three gas giant planets orbiting Kepler-31 were discovered in early 2011, albeit with large false alarm probability, and were confirmed in 2012.{{citation|arxiv=1102.0543|title=Architecture and Dynamics of Kepler 'S Candidate Multiple Transiting Planet Systems|year=2011|doi=10.1088/0067-0049/197/1/8 |last1=Lissauer |first1=Jack J. |last2=Ragozzine |first2=Darin |last3=Fabrycky |first3=Daniel C. |last4=Steffen |first4=Jason H. |last5=Ford |first5=Eric B. |last6=Jenkins |first6=Jon M. |last7=Shporer |first7=Avi |last8=Holman |first8=Matthew J. |last9=Rowe |first9=Jason F. |last10=Quintana |first10=Elisa V. |last11=Batalha |first11=Natalie M. |last12=Borucki |first12=William J. |last13=Bryson |first13=Stephen T. |last14=Caldwell |first14=Douglas A. |last15=Carter |first15=Joshua A. |last16=Ciardi |first16=David |last17=Dunham |first17=Edward W. |last18=Fortney |first18=Jonathan J. |last19=Gautier, Iii |first19=Thomas N. |last20=Howell |first20=Steve B. |last21=Koch |first21=David G. |last22=Latham |first22=David W. |last23=Marcy |first23=Geoffrey W. |last24=Morehead |first24=Robert C. |last25=Sasselov |first25=Dimitar |journal=The Astrophysical Journal Supplement Series |volume=197 |issue=1 |page=8 |bibcode=2011ApJS..197....8L |s2cid=43095783 }}[https://www.researchgate.net/publication/221659891_Transit_Timing_Observations_from_Kepler_IV_Confirmation_of_4_MultiplePlanet_Systems_by_Simple_Physical_Models Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models] The planets form a resonant chain, with orbital periods ratio 1:2:4, although 20% probability exists that these period ratios may be coincidental.{{citation|arxiv=1903.09474|title=The role of dissipative evolution for three-planet, near-resonant extrasolar systems|year=2019|doi=10.1051/0004-6361/201935259|last1=Pichierri|first1=Gabriele|last2=Batygin|first2=Konstantin|last3=Morbidelli|first3=Alessandro|journal=Astronomy & Astrophysics|volume=625|pages=A7|bibcode=2019A&A...625A...7P |s2cid=85459759}}
{{OrbitboxPlanet begin
| table_ref = [https://exoplanet.eu/catalog/kepler_31_d--2217/ Planet Kepler-31 d at exoplanets.eu]
}}
{{OrbitboxPlanet
| exoplanet= .04(unconfirmed)
| mass=
| semimajor = 0.0937
| period = 9.61730282{{±|3.35e-5}}
| radius = 0.173
}}
{{OrbitboxPlanet
| exoplanet = b
| mass = <6.8
| semimajor = 0.16
| period = 20.8613
| radius = 0.38{{±|0.07}}
}}
{{OrbitboxPlanet
| exoplanet = c
| mass = <4.7
| semimajor = 0.26
| period = 42.6318
| radius = 0.38{{±|0.07}}
}}
{{OrbitboxPlanet
| exoplanet = d
| mass =
| semimajor = 0.39
| period = 87.648901{{±|0.000801}}
| radius = 0.407{{±|0.099}}
}}
{{Orbitbox end}}
References
{{reflist|refs=
{{Cite Gaia DR3|2128013019361703936}}
{{Cite constellation|Kepler-31}}
}}
{{Sky|19|36|05.523|+|45|51|11.09}}
{{Stars of Cygnus}}
Category:Cygnus (constellation)
Category:G-type main-sequence stars