Observation data Epoch J2000 Equinox J2000 | |
---|---|
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
mas/
yr
[2] Dec.: −66.773 mas/ yr [2] |
Parallax (π) | 5.0627 ± 0.0110 mas [2] |
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]
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]
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 ME as of 2023 [update]. [5]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
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
mas/
yr
[2] Dec.: −66.773 mas/ yr [2] |
Parallax (π) | 5.0627 ± 0.0110 mas [2] |
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]
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]
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 ME as of 2023 [update]. [5]