| 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−Vcolor index | 0.64 |
| Astrometry | |
| Radial velocity (Rv) | −44.00±0.12[1] km/s |
| Proper motion (μ) | RA: 195.306mas/yr[1] Dec.: -117.335mas/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 | |
| BD+48 4112,Gaia DR2 1943363751009454976,HD 222155,HIP 116616,SAO 53211,TYC 3646-2286-1,2MASS J23380027+4859475[5] | |
| Database references | |
| SIMBAD | data |
HD 222155 is astar in the northernconstellation ofAndromeda.[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 anapparent visual magnitude of 7.1. The imaging survey in 2017 did not detect any stellar companions to HD 222155.[6]
This is an oldmain sequence star with astellar 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 asuperjovian 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 viaastrometry.[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 or115+13 −16° | — |
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