Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Andromeda |
Right ascension | 23h 38m 00.30719s [1] |
Declination | +48° 59′ 47.4874″ [1] |
Apparent magnitude (V) | 7.1 [2] |
Characteristics | |
Evolutionary stage | main sequence star |
Spectral type | G0V |
B−V color index | 0.64 |
Astrometry | |
Radial velocity (Rv) | −44.00±0.12 [1] km/s |
Proper motion (μ) | RA: 195.306 mas/yr [1] Dec.: -117.335 mas/yr [1] |
Parallax (π) | 19.8020 ± 0.0160 mas [1] |
Distance | 164.7 ± 0.1 ly (50.50 ± 0.04 pc) |
Details [2] [3] [4] | |
Mass | 1.21±0.10 M☉ |
Radius | 1.85±0.04 R☉ |
Luminosity | 3.2 L☉ |
Surface gravity (log g) | 4.10±0.13 cgs |
Temperature | 5720±44 K |
Metallicity [Fe/H] | -0.11±0.05 dex |
Rotational velocity (v sin i) | 3.2±1.0 km/s |
Age | 8.2±0.7 Gyr |
Other designations | |
Database references | |
SIMBAD | data |
HD 222155 is a star in the northern constellation of Andromeda. [5] It is a yellow star that can be viewed with binoculars or a small telescope, but is too faint to be seen with the naked eye at an apparent visual magnitude of 7.1. The imaging survey in 2017 did not detect any stellar companions to HD 222155. [6]
This is an old main sequence star with a stellar classification of G0V; [5] a star that is nearing an exhaustion of its hydrogen fuel. It is already beginning to expand its gaseous envelope, [2] having radius of 1.85R☉. [3] The star is relatively depleted of heavy elements, having about 80% of solar abundance, and has weak yet noticeable ultraviolet flare activity. [7] [8]
Based on radial velocity data gathered in 2007-2011, the discovery of a superjovian planet b outside the habitable zone [4] was announced in May 2012. [2] The stellar and planetary parameters were refined in 2016. [3] In 2023, the inclination and true mass of HD 222155 b were measured via astrometry. [9]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 2.1+0.3 −0.2 MJ | 4.7±0.1 | 3470+102 −106 | 0.34±0.09 | 66+14 −11 or 115+13 −16 ° | — |
79 Ceti, also known as HD 16141, is a binary star system located 123 light-years from the Sun in the southern constellation of Cetus. It has an apparent visual magnitude of +6.83, which puts it below the normal limit for visibility with the average naked eye. The star is drifting closer to the Earth with a heliocentric radial velocity of −51 km/s.
BD−10°3166 is a K-type main sequence star approximately 268 light-years away in the constellation of Crater. It was inconspicuous enough not be included in the Draper catalog (HD). The Hipparcos satellite also did not study it, so its true distance is poorly known. The distance measured by the Gaia spacecraft of 268 light years rules out a suggested companion star, LP 731-076, being its true binary star companion.
HD 219134 is a main-sequence star in the constellation of Cassiopeia. It is smaller and less luminous than the Sun, with a spectral class of K3V, which makes it an orange-hued star. HD 219134 is relatively close to our system, with an estimated distance of 21.34 light years. This star is close to the limit of apparent magnitude that can still be seen by the unaided eye. The limit is considered to be magnitude 6 for most observers. This star has a magnitude 9.4 optical companion at an angular separation of 106.6 arcseconds.
HD 125612 is a binary star system with three exoplanetary companions in the equatorial constellation of Virgo. It is too dim to be visible to the naked eye, having an apparent visual magnitude of 8.31. The system is located at a distance of 188 light years from the Sun based on parallax measurements, but it is drifting closer with a radial velocity of −18 km/s.
HD 81040 is a star in the equatorial constellation of Leo. With an apparent visual magnitude of +7.73 it is too dim to be visible to the naked eye but can be viewed with a small telescope. The star is located at a distance of 112 light years from the Sun based on parallax. It is drifting further away with a radial velocity of +49 km/s, having come to within 48 light-years some 527,000 years ago.
HD 136118 is a star in the Serpens Caput section of the Serpens constellation. The star is too dim to be readily visible to the naked eye, having an apparent visual magnitude of 6.93. It is located at a distance of 165 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −3 km/s.
HD 72659 is a star in the equatorial constellation of Hydra. With an apparent visual magnitude of 7.46, his yellow-hued star is too faint to be viewed with the naked eye. Parallax measurements provide a distance estimate of 169.4 light years from the Sun, and it has an absolute magnitude of 3.98. The star is drifting closer with a radial velocity of −18.3 km/s.
HD 213240 is a possible binary star system in the constellation Grus. It has an apparent visual magnitude of 6.81, which lies below the limit of visibility for normal human sight. The system is located at a distance of 133.5 light years from the Sun based on parallax. The primary has an absolute magnitude of 3.77.
HD 87883 is star in the northern constellation of Leo Minor. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 7.56. The star is located at a distance of 59.7 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +9.3 km/s. It has an absolute magnitude of 6.27.
HD 126614 is a trinary star system in the equatorial constellation of Virgo. The primary member, designated component A, is host to an exoplanetary companion. With an apparent visual magnitude of 8.81, it is too faint to be seen with the naked eye. The system is located at a distance of 239 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −33 km/s.
Gliese 179 is a small red dwarf star with an exoplanetary companion in the equatorial constellation of Orion. It is much too faint to be visible to the naked eye with an apparent visual magnitude of 11.94. The system is located at a distance of 40.5 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of –9 km/s. It is a high proper motion star, traversing the celestial sphere at an angular rate of 0.370″·yr−1.
Kepler-51 is a Sun-like star that is only about 500 million years old. It is orbited by three super-puff planets—Kepler-51b, c, and d—which have the lowest known densities of any exoplanet. The planets are all Jupiter-sized but with masses only a few times Earth's.
HD 217786 is a binary star system in the equatorial constellation of Pisces. With an apparent visual magnitude of 7.78, it requires binoculars or a small telescope to view. The system is located at a distance of 181 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +10 km/s. Kinematically, the star system belongs to the thin disk population of the Milky Way.
HD 7449 is a binary star system about 126 light-years way. The primary star, HD 7449 A, is a main-sequence star belonging to the spectral class F9.5. It is younger than the Sun. The primary star is slightly depleted of heavy elements, having 80% of solar abundance.
HD 142245 is a hierarchical triple star system about 318 light-years away.
HD 197037 is a binary star system. Its primary or visible star, HD 197037A, is a F-type main-sequence star. Its surface temperature is 6150±34 K. HD 197037A is depleted in heavy elements compared to the Sun, with a metallicity Fe/H index of −0.16±0.03, but is younger at an age of 3.408±0.924 billion years.
HD 221420 is a likely binary star system in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.81, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of 102 light years but is receding with a heliocentric radial velocity of 26.5 km/s.