Astronomy:Kepler-22
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cygnus[1] |
| Right ascension | 19h 16m 52.19023s[2] |
| Declination | +47° 53′ 03.9486″[2] |
| Apparent magnitude (V) | 11.664[3] |
| Characteristics | |
| Spectral type | G5V[4] |
| Astrometry | |
| Radial velocity (Rv) | −4.50±0.51[2] km/s |
| Proper motion (μ) | RA: −39.589[2] mas/yr Dec.: −66.773[2] mas/yr |
| Parallax (π) | 5.0627 ± 0.0110[2] mas |
| Distance | 644 ± 1 ly (197.5 ± 0.4 pc) |
| Absolute magnitude (MV) | ~5.27 |
| Absolute bolometric magnitude (Mbol) | ~4.98 |
| Details | |
| Mass | 0.857+0.051 −0.043[5] M☉ |
| Radius | 0.869±0.011[5] R☉ |
| Luminosity (bolometric) | 0.79 ± 0.04[3] L☉ |
| Luminosity (visual, LV) | ~0.67 L☉ |
| Temperature | 5596±61[5] K |
| Metallicity [Fe/H] | −0.255±0.065[5] dex |
| Rotational velocity (v sin i) | 0.6 ± 1.0[3] km/s |
| Age | 7.0+4.0 −4.2[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| KIC | data |
| Extrasolar Planets Encyclopaedia | data |
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″.[2] With an apparent visual magnitude of 11.7,[3] 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).[7] The estimated distance to Kepler-22 is 644 light-years (197 parsecs).[2]
Stellar characteristics
Kepler-22 is slightly smaller and cooler than the Sun,[8] with a lower abundance of elements having more mass than helium.[3] It has a spectral type of G5V, while the luminosity class remains undetermined.[4] This star is radiating 79%[3] of the Sun's luminosity from its outer atmosphere at an effective temperature of 5,518 K,[3] giving it the yellow-hued glow of a G-type star.[9] A projected rotational velocity of 0.6 km/s[3] suggests it has a long period of rotation. No flare activity has been detected.[10]
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.[11][12] This was significant in that it was the first relatively small exoplanet (about 2.4 R⊕)[12] confirmed to be orbiting within a star's habitable zone.[13] Its size suggests that it is not 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).[5]
References
- ↑ "Cygnus – constellation boundary", The Constellations, International Astronomical Union, http://www.iau.org/public/constellations/#cyg, retrieved 2011-12-15
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 "Kepler-22b". http://kepler.nasa.gov/Mission/discoveries/kepler22b/.
- ↑ 4.0 4.1 Schneider, Jean, Star: Kepler-22, https://exoplanet.eu/catalog/kepler_22_b--1029/, retrieved 2020-12-17
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 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.
- ↑ "GSC 03546-02301 -- Star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=%406293726&Name=GSC%2003546-02301, retrieved 2011-12-08
- ↑ 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.
- ↑ "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
- ↑ 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.
- ↑ 12.0 12.1 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.
Coordinates: 
19h 16m 52.2s, +47° 53′ 4.2″
 |  |
