| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 33m 35.555s[1] |
| Declination | −11° 37′ 18.73″[1] |
| Apparent magnitude (V) | 8.05 ± 0.01[2] |
| Characteristics | |
| Spectral type | G5 V[2] + DA[3] |
| B−Vcolor index | +0.658±0.002[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.971±0.0011[4] km/s |
| Proper motion (μ) | RA: −169.971mas/yr[1] Dec.: 81.000mas/yr[1] |
| Parallax (π) | 17.9082±0.0379 mas[1] |
| Distance | 182.1 ± 0.4 ly (55.8 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.1±0.1[2] |
| Position (relative to HD 109271 A)[3] | |
| Component | HD 109271 B |
| Epoch of observation | 2018 |
| Angular distance | 5.425″ |
| Position angle | 267.354° |
| Projected separation | 304AU |
| Details[2] | |
| HD 109271 A | |
| Mass | 1.047±0.024 M☉ |
| Radius | 1.295+0.023 −0.020[5] R☉ |
| Luminosity | 1.649±0.008[5] L☉ |
| Surface gravity (log g) | 4.28±0.10 cgs |
| Temperature | 5,783±62 K |
| Metallicity [Fe/H] | 0.10±0.05 dex |
| Rotational velocity (v sin i) | 2.7 km/s |
| Age | 7.3±1.2 Gyr |
| HD 109271 B | |
| Mass | ~0.6[3] M☉ |
| Other designations | |
| BD−10° 3494,HD 109271,HIP 61300,SAO 157362,LTT 4770[6] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 109271 is a widebinary star system in theconstellation ofVirgo. The brighter member of the binary has a pair of orbitingexoplanets. With anapparent visual magnitude of 8.05,[2] it cannot be seen with the naked eye.Parallax measurements made byGaia put the star at a distance of 181 light-years (55 parsecs) away from the Sun, but it is drifting closer with aradial velocity of −5 km/s.[4] The system shows a highproper motion, traversing thecelestial sphere at anangular rate of0.232 arcsec yr−1.[7]
The primary component is an ordinaryG-type main-sequence star with astellar classification of G5 V. It is a much older star than the Sun with an age of about 7.3 billion years, and is spinning with aprojected rotational velocity of 2.7 km/s.[2] This star has 7% more mass than the Sun and a 30% greater girth.[5] The abundance of iron, a measure of the star'smetallicity, is similar but slightly higher than in the Sun.[2] It is radiating 1.65[5] times the luminosity of the Sun from itsphotosphere at aneffective temperature of around 5,783 K.[2]
In 2020, awhite dwarf companion of 0.6 M☉ was found orbiting the primary at anangular separation of5.4″ along aposition angle of 267°. At the distance of this system, this corresponds to aprojected separation of304 AU. That is, they are physically separated by at least this distance. Additional stellar companions are ruled out down to a separation of0.15″ from the primary.[3]
From 2003 to 2012, the star was under observance from theHigh Accuracy Radial Velocity Planet Searcher (HARPS).[2] In 2012, two eccentric hot Neptune-massplanets were deduced byradial velocity. They were published in January 2013. These are close to a 1:4 resonance, so the system is similar toHD 69830. A third Neptune in the Venus zone was hypothesised from the data. These planets managed to survive the post main-sequence epoch of the companion star, when it shed much of its original mass.[3]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.054 ± 0.004 MJ | 0.079 ± 0.001 | 7.8543 ± 0.0009 | 0.25 ± 0.08 | — | — |
| c | >0.076 ± 0.007 MJ | 0.196 ± 0.003 | 30.93 ± 0.02 | 0.15 ± 0.09 | — | — |
| d(unconfirmed) | >1.3 neptuneMJ | 1 | 430 | 0.36 | — | — |
