Kepler-28

Kepler-28
	; Kepler-28 compared to the Sun
Observation data; Epoch J2000 Equinox J2000
Constellation	Cygnus
Right ascension	19h 28m 32.8905s
Declination	+42° 25′ 45.959″
Apparent magnitude (V)	15.036
Characteristics
Spectral type	M0V
Astrometry
Radial velocity (Rv)	−26.99±6.00 km/s
Proper motion (μ)	RA: −0.463(21) mas/yr ; Dec.: 11.691(21) mas/yr
Parallax (π)	2.2537 ± 0.0185 mas
Distance	1,450 ± 10 ly ; (444 ± 4 pc)
Details
Mass	0.684±0.026 M☉
Radius	0.664±0.013 R☉
Temperature	4499±75 K
Metallicity [Fe/H]	−0.17±0.11 dex
Rotation	17.951±0.016 days
Rotational velocity (v sin i)	0.6 km/s
Age	2.2 Gyr
Other designations
	KOI-870, KIC 6949607, 2MASS J19283288+4225459
Database references
SIMBAD	data
KIC	data

Kepler-28 is an M-type main-sequence star about 1,450 light-years (440 parsecs) away in the northern constellation of Cygnus.^[2] With an apparent visual magnitude of 15.036,^[3] this star is too faint to be seen with the naked eye. It is orbited by two exoplanets.

Planetary system

The two transiting planets of Kepler-28 were discovered in 2011 using the Kepler space telescope, and were confirmed in early 2012.^[9] They are both warm sub-Neptune gas planets.^[7] The planetary parameters were updated in 2023, with lower values for all of mass, radius, and density compared to previous estimates.^[5]

The Kepler-28 planetary system^[4]^[5]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	1.63+0.51 −0.40 $M$ _🜨	0.062	5.91213(17)	<0.08	—	1.959+0.043 −0.042 $R$ _🜨
c	2.06+0.70 −0.52 $M$ _🜨	0.081	8.98597(27)	0.017+0.023 −0.014	—	1.857±0.042 $R$ _🜨

References

^ "Cygnus – constellation boundary", The Constellations, International Astronomical Union, retrieved 2011-12-15
^ ^a ^b ^c ^d ^e ^f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
^ ^a ^b ^c Kepler-28b, NASA Ames Research Center, archived from the original on 2012-05-03, retrieved 2011-12-06
^ ^a ^b ^c Muirhead, Philip S.; Hamren, Katherine; et al. (May 2012). "Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars". The Astrophysical Journal Letters. 750 (2): L37. arXiv:1109.1819. Bibcode:2012ApJ...750L..37M. doi:10.1088/2041-8205/750/2/L37.
^ ^a ^b ^c ^d ^e Leleu, A.; Delisle, J.-B.; et al. (January 2023). "Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets". Astronomy & Astrophysics. 669: A117. arXiv:2207.07456. Bibcode:2023A&A...669A.117L. doi:10.1051/0004-6361/202244132.
^ McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11.
^ ^a ^b Cubillos, Patricio; Erkaev, Nikolai V.; Juvan, Ines; Fossati, Luca; Johnstone, Colin P.; Lammer, Helmut; Lendl, Monika; Odert, Petra; Kislyakova, Kristina G. (2016), "An overabundance of low-density Neptune-like planets", Monthly Notices of the Royal Astronomical Society, 466 (2): 1868–1879, arXiv:1611.09236, Bibcode:2017MNRAS.466.1868C, doi:10.1093/mnras/stw3103, S2CID 119408956
^ "Kepler-28". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 January 2017.
^ Steffen, Jason H.; Fabrycky, Daniel C.; Ford, Eric B.; Carter, Joshua A.; Desert, Jean-Michel; Fressin, Francois; Holman, Matthew J.; Lissauer, Jack J.; Moorhead, Althea V.; Rowe, Jason F.; Ragozzine, Darin; Welsh, William F.; Batalha, Natalie M.; Borucki, William J.; Buchhave, Lars A.; Bryson, Steve; Caldwell, Douglas A.; Charbonneau, David; Ciardi, David R.; Cochran, William D.; Endl, Michael; Everett, Mark E.; Gautier III, Thomas N.; Gilliland, Ron L.; Girouard, Forrest R.; Jenkins, Jon M.; Horch, Elliott; Howell, Steve B.; Isaacson, Howard; et al. (2012), Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations, arXiv:1201.5412, Bibcode:2012MNRAS.421.2342S, doi:10.1111/j.1365-2966.2012.20467.x, S2CID 11898578

[IAU_const-1] "Cygnus – constellation boundary", The Constellations, International Astronomical Union, retrieved 2011-12-15

[Gaia_DR3-2] ^ ^a ^b ^c ^d ^e ^f Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.

[nasa_ames-3] Kepler-28b, NASA Ames Research Center, archived from the original on 2012-05-03, retrieved 2011-12-06

[Muirhead2012-4] Muirhead, Philip S.; Hamren, Katherine; et al. (May 2012). "Characterizing the Cool Kepler Objects of Interests. New Effective Temperatures, Metallicities, Masses, and Radii of Low-mass Kepler Planet-candidate Host Stars". The Astrophysical Journal Letters. 750 (2): L37. arXiv:1109.1819. Bibcode:2012ApJ...750L..37M. doi:10.1088/2041-8205/750/2/L37.

[Leleu2023-5] Leleu, A.; Delisle, J.-B.; et al. (January 2023). "Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets". Astronomy & Astrophysics. 669: A117. arXiv:2207.07456. Bibcode:2023A&A...669A.117L. doi:10.1051/0004-6361/202244132.

[McQuillan2013-6] McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11.

[Cubillos2016-7] Cubillos, Patricio; Erkaev, Nikolai V.; Juvan, Ines; Fossati, Luca; Johnstone, Colin P.; Lammer, Helmut; Lendl, Monika; Odert, Petra; Kislyakova, Kristina G. (2016), "An overabundance of low-density Neptune-like planets", Monthly Notices of the Royal Astronomical Society, 466 (2): 1868–1879, arXiv:1611.09236, Bibcode:2017MNRAS.466.1868C, doi:10.1093/mnras/stw3103, S2CID 119408956

[SIMBAD-8] "Kepler-28". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 January 2017.

[Steffen2012-9] Steffen, Jason H.; Fabrycky, Daniel C.; Ford, Eric B.; Carter, Joshua A.; Desert, Jean-Michel; Fressin, Francois; Holman, Matthew J.; Lissauer, Jack J.; Moorhead, Althea V.; Rowe, Jason F.; Ragozzine, Darin; Welsh, William F.; Batalha, Natalie M.; Borucki, William J.; Buchhave, Lars A.; Bryson, Steve; Caldwell, Douglas A.; Charbonneau, David; Ciardi, David R.; Cochran, William D.; Endl, Michael; Everett, Mark E.; Gautier III, Thomas N.; Gilliland, Ron L.; Girouard, Forrest R.; Jenkins, Jon M.; Horch, Elliott; Howell, Steve B.; Isaacson, Howard; et al. (2012), Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations, arXiv:1201.5412, Bibcode:2012MNRAS.421.2342S, doi:10.1111/j.1365-2966.2012.20467.x, S2CID 11898578

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Kepler-28

Planetary system

References

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