HD 109271
HD 109271 is a wide binary star system in the constellation of Virgo. The brighter member of the binary has a pair of orbiting exoplanets. With an apparent visual magnitude of 8.05, it cannot be seen with the naked eye. Parallax measurements made by Gaia put the star at a distance of 181 light-years (55 parsecs) away from the Sun, but it is drifting closer with a radial velocity of −5 km/s. The system shows a high proper motion, traversing the celestial sphere at an angular rate of 0.232 arcsec yr−1.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 33m 35.555s |
| Declination | −11° 37′ 18.73″ |
| Apparent magnitude (V) | 8.05 ± 0.01 |
| Characteristics | |
| Spectral type | G5 V + DA |
| B−V color index | +0.658±0.002 |
| Astrometry | |
| Radial velocity (Rv) | −4.971±0.0011 km/s |
| Proper motion (μ) | RA: −169.971 mas/yr Dec.: 81.000 mas/yr |
| Parallax (π) | 17.9082 ± 0.0379 mas |
| Distance | 182.1 ± 0.4 ly (55.8 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.1±0.1 |
| Position (relative to HD 109271 A) | |
| Component | HD 109271 B |
| Epoch of observation | 2018 |
| Angular distance | 5.425″ |
| Position angle | 267.354° |
| Projected separation | 304 AU |
| Details | |
| HD 109271 A | |
| Mass | 1.047±0.024 M☉ |
| Radius | 1.295+0.023 −0.020 R☉ |
| Luminosity | 1.649±0.008 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 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
The primary component is an ordinary G-type main-sequence star with a stellar 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 a projected rotational velocity of 2.7 km/s. This star has 7% more mass than the Sun and a 30% greater girth. The abundance of iron, a measure of the star's metallicity, is similar but slightly higher than in the Sun. It is radiating 1.65 times the luminosity of the Sun from its photosphere at an effective temperature of around 5,783 K.
In 2020, a white dwarf companion of 0.6 M☉ was found orbiting the primary at an angular separation of 5.4″ along a position angle of 267°. At the distance of this system, this corresponds to a projected separation of 304 AU. That is, they are physically separated by at least this distance. Additional stellar companions are ruled out down to a separation of 0.15″ from the primary.