Kepler-56 is a red giant[8] in the constellation Cygnus. It is located roughly 3,030 light-years (930 pc) away[2] from the solar system and has slightly more mass than the Sun.

Characteristics

Kepler-56 is a red giant star. This means it is no longer fusing hydrogen in its core and is off the main sequence. Its mass is around 1.3 M☉. Its radius is about 4.2 R☉, putting the star's density at about 0.025 g/cm3. For reference, the Sun's density is about 1.408 g/cm3. Kepler-56's metallicity is about 0.0251 Z0/X0[clarification needed]. Its luminosity is about 9.6 L☉, and its effective temperature is 4,973 K (4,700 °C; 8,492 °F).[4]

Kepler-56 is about 3.9 billion years old,[4] placing it as about 600 million years younger than the Sun. Its apparent magnitude is +13, making it too dim to be visible to the naked eye.

Planetary system

In 2012, scientists discovered a two-planet planetary system around Kepler-56 via the transit method. Asteroseismological studies revealed that the orbits of Kepler-56b and Kepler-56c are coplanar but about 45° misaligned to the host star's equator. In addition, follow-up radial velocity measurements showed evidence of a gravitational perturbator.[8] It was confirmed in 2016 that the perturbations are caused by a third, non-transiting planet: Kepler-56d.[9]

The planetary system is very compact but is dynamically stable.[10]

Kepler-56 is expanding. As a result, it will devour Kepler-56b and Kepler-56c in 130 and 155 million years, respectively.[11][12] 56d will be far enough to survive its parent star's red giant phase.

The Kepler-56 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination
(°)		 Radius
b[13][14] 22.25344 M🜨 0.1028 10.5034294 — 79.640 3.61 R🜨
c[15][16] 0.569 MJ 0.1652 21.4050484 — 81.930 7.84 R🜨
d[9] >5.61±0.38 MJ 2.16±0.08 1002±5 0.20±0.01 — —

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
  2. 1 2 3 4 5 6 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.
  3. ↑ Furlan, E.; Ciardi, D. R.; Everett, M. E.; Saylors, M.; Teske, J. K.; Horch, E. P.; Howell, S. B.; Van Belle, G. T.; Hirsch, L. A.; Gautier, T. N., III; Adams, E. R.; Barrado, D.; Cartier, K. M. S.; Dressing, C. D.; Dupree, A. K.; Gilliland, R. L.; Lillo-Box, J.; Lucas, P. W.; Wang, J. (2017). "The Kepler Follow-up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging". The Astronomical Journal. 153 (2): 71. arXiv:1612.02392. Bibcode:2017AJ....153...71F. doi:10.3847/1538-3881/153/2/71.
  4. 1 2 3 4 5 6 7 8 Fellay, L.; Buldgen, G.; et al. (2021). "Asteroseismology of evolved stars to constrain the internal transport of angular momentum. IV. Internal rotation of Kepler 56 from an MCMC analysis of the rotational splittings". Astronomy & Astrophysics. 654. 12. arXiv:2108.02670. doi:10.1051/0004-6361/202140518. S2CID 239652877.
  5. ↑ Jönsson, Henrik; Holtzman, Jon A.; Allende Prieto, Carlos; Cunha, Katia; García-Hernández, D. A.; Hasselquist, Sten; Masseron, Thomas; Osorio, Yeisson; Shetrone, Matthew; Smith, Verne; Stringfellow, Guy S.; Bizyaev, Dmitry; Edvardsson, Bengt; Majewski, Steven R.; Mészáros, Szabolcs; Souto, Diogo; Zamora, Olga; Beaton, Rachael L.; Bovy, Jo; Donor, John; Pinsonneault, Marc H.; Poovelil, Vijith Jacob; Sobeck, Jennifer (2020). "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South". The Astronomical Journal. 160 (3): 120. arXiv:2007.05537. Bibcode:2020AJ....160..120J. doi:10.3847/1538-3881/aba592.
  6. 1 2 Matsuno, Tadafumi; Starkenburg, Else; Balbinot, Eduardo; Helmi, Amina (2024). "Improving metallicity estimates for very metal-poor stars in the Gaia DR3 GSP-Spec catalog". Astronomy and Astrophysics. 685: A59. arXiv:2212.11639. Bibcode:2024A&A...685A..59M. doi:10.1051/0004-6361/202245762.
  7. ↑ "Kepler-56". SIMBAD. Centre de données astronomiques de Strasbourg.
  8. 1 2 Huber, Daniel; et al. (2013). "Stellar Spin-Orbit Misalignment in a Multiplanet System". Science. 342 (6156): 331–334. arXiv:1310.4503. Bibcode:2013Sci...342..331H. doi:10.1126/science.1242066. PMID 24136961.
  9. 1 2 Otor, Oderah Justin; Montet, Benjamin T.; et al. (22 September 2016). "The Orbit and Mass of the Third Planet in the Kepler-56 System". The Astronomical Journal. 152 (6). Cornell University: 165. arXiv:1608.03627v2. Bibcode:2016AJ....152..165O. doi:10.3847/0004-6256/152/6/165. ISSN 0004-6256.
  10. ↑ Denham, Paul; Naoz, Smadar; et al. (29 October 2018). "Hidden planetary friends: on the stability of two-planet systems in the presence of a distant, inclined companion". Monthly Notices of the Royal Astronomical Society. 482 (3): 4146–4154. arXiv:1802.00447. doi:10.1093/mnras/sty2830. ISSN 0035-8711.
  11. ↑ Kramer, Miriam (June 10, 2014). "Chow Down! Star Will Devour 2 Alien Planets". Space.com. Retrieved 24 February 2022.
  12. ↑ Li, Gongjie; Naoz, Smadar; et al. (October 1, 2014). "The Dynamics of the Multi-planet System Orbiting Kepler-56". The Astrophysical Journal. 794 (2): 131. arXiv:1407.2249. Bibcode:2014ApJ...794..131L. doi:10.1088/0004-637X/794/2/131. S2CID 56224888.
  13. ↑ "Planet Kepler-56 b". Extrasolar Planets Encyclopaedia. Retrieved 2013-10-18.
  14. ↑ "KOI-1241.02 -- Extra-solar Confirmed Planet". SIMBAD.
  15. ↑ "Planet Kepler-56 c". Extrasolar Planets Encyclopaedia. 2018.
  16. ↑ "KOI-1241.01 -- Extra-solar Confirmed Planet". SIMBAD.
source: https://en.wikipedia.org/wiki/Kepler-56