Astronomy:Kepler-22
Kepler-22 is a Sun-like star in the northern constellation of Cygnus, the swan, that is orbited by a planet found to be unequivocally within the star's habitable zone. It is located at the celestial coordinates: Right Ascension 19h 16m 52.2s, Declination +47° 53′ 3.9″.[1] With an apparent visual magnitude of 11.7,[2] this star is too faint to be seen with the naked eye. It can be viewed with a telescope having an aperture of at least 4 in (10 cm).[3] The estimated distance to Kepler-22 is 644 light-years (197 parsecs).[1]
Stellar characteristics
Kepler-22 is slightly smaller and cooler than the Sun,[4] with a lower abundance of elements having more mass than helium.[2] It has a spectral type of G5V, while the luminosity class remains undetermined.[5] This star is radiating 79%[2] of the Sun's luminosity from its outer atmosphere at an effective temperature of 5,518 K,[2] giving it the yellow-hued glow of a G-type star.[6] A projected rotational velocity of 0.6 km/s[2] suggests it has a long period of rotation. No flare activity has been detected.[7]
Planetary system
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | <9.1 M⊕ | 0.812+0.011 −0.013 |
289.863876±0.000013 | <0.72 | 89.764+0.025 −0.042° |
2.10±0.12 R⊕ |
On December 5, 2011, scientists from the Kepler mission announced that an exoplanet, Kepler-22b, had been discovered orbiting in the star's habitable zone by NASA's Kepler spacecraft.[9][10] This was significant in that it was the first relatively small exoplanet (about 2.4 R⊕)[10] confirmed to be orbiting within a star's habitable zone.[11] Its size suggests that it is not likely to be a rocky planet and is more likely to be a mini-Neptune or ocean world; while its mass has not been measured, radial velocity observations have set an upper limit of 9.1 M⊕ as of 2023[update].[8]
In popular culture
Kepler-22b is the source of the extraterrestrial signal which starts the events in the television show Pluribus.[12]
References
- ↑ 1.0 1.1 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 "Kepler-22b". http://kepler.nasa.gov/Mission/discoveries/kepler22b/.
- ↑ Sherrod, P. Clay; Koed, Thomas L. (2003), A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations, Astronomy Series, Courier Dover Publications, p. 9, ISBN 0486428206, https://books.google.com/books?id=4zjv84hHNPcC&pg=PA9
- ↑ "Kepler Confirms First Planet in Habitable Zone of Sun-Like Star". Universe Today. 2011-12-05. http://www.universetoday.com/91564/kepler-confirms-first-planet-in-habitable-zone-of-sun-like-star/#more-91564.
- ↑ Schneider, Jean, Star: Kepler-22, https://exoplanet.eu/catalog/kepler_22_b--1029/, retrieved 2020-12-17
- ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16
- ↑ Armstrong, D. J.; Pugh, C. E.; Broomhall, A.-M.; Brown, D. J. A.; Lund, M. N.; Osborn, H. P.; Pollacco, D. L. (2015), "The Host Stars of Kepler's Habitable Exoplanets: Superflares, Rotation and Activity", Monthly Notices of the Royal Astronomical Society 455 (3): 3110–3125, doi:10.1093/mnras/stv2419
- ↑ 8.0 8.1 Bonomo, A. S. et al. (April 2023). "Cold Jupiters and improved masses in 38 Kepler and K2 small-planet systems from 3661 high-precision HARPS-N radial velocities. No excess of cold Jupiters in small-planet systems". Astronomy & Astrophysics. doi:10.1051/0004-6361/202346211. Bibcode: 2023A&A...677A..33B.
- ↑ Borucki, William J. et al. (February 2012). "Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star". The Astrophysical Journal 745 (2): 120. doi:10.1088/0004-637X/745/2/120. Bibcode: 2012ApJ...745..120B.
- ↑ 10.0 10.1 Boyle, Rebecca (December 5, 2011). "Kepler Team Confirms First Earth-like planet in a habitable zone, And Finds 1,094 More Worlds". Popular Science. http://www.popsci.com/science/article/2011-12/Kepler-team-confirms-first-earth-planet-habitable-zone-and-finds-1094-more-worlds.
- ↑ "NASA Telescope Confirms Alien Planet in Habitable Zone". Space.com. 2011-12-05. http://www.space.com/13821-nasa-kepler-alien-planets-habitable-zone.html.
- ↑ "Charm Offensive". Pluribus. Season 1. Episode 8. 2025-12-19. Event occurs at 21:13. Apple TV.
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Coordinates: 
19h 16m 52.2s, +47° 53′ 4.2″
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