HD 210702 is an orange subgiant star located approximately 177 light-years away in the constellation of Pegasus. With a mass of 1.8 times that of the Sun, the star spent its main-sequence life as an A-type star. The visual luminosity is 11.38 times that of the Sun and the magnitude is near the naked-eye limit, but binoculars can easily see it.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 22h 11m 51.3309s[1] |
| Declination | +16° 02′ 25.9959″[1] |
| Apparent magnitude (V) | 5.939 |
| Characteristics | |
| Spectral type | K1IV |
| U−B color index | 0.73 |
| B−V color index | 0.951[2] |
| R−I color index | 0.49 |
| Astrometry | |
| Radial velocity (Rv) | 10.9 ± 2 km/s |
| Proper motion (μ) | RA: −3.241±0.156[1] mas/yr Dec.: −17.156±0.160[1] mas/yr |
| Parallax (π) | 18.4231 ± 0.0783 mas[1] |
| Distance | 177.0 ± 0.8 ly (54.3 ± 0.2 pc) |
| Absolute magnitude (MV) | 2.201 |
| Details | |
| Mass | 1.68 (1.50–1.84)[2] M☉ |
| Radius | 5.2314±0.1171[3] R☉ |
| Luminosity | 12.838±0.5569[3] L☉ |
| Surface gravity (log g) | 3.19 ± 0.08[2] cgs |
| Temperature | 4780±18[3] K |
| Metallicity [Fe/H] | 0.03 [3] dex |
| Age | 5.0[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The star shows variability in its radial velocity consistent with a planet-mass companion in a Keplerian orbit,[5] and one was duly discovered in April 2007, from observations at Lick and Keck Observatories in Mount Hamilton (California) and Mauna Kea (Hawai'i), United States.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥1.808±0.097 MJ | 1.148±0.057 | 354.10±0.70 | 0.028±0.034 | — | — |
Stars of Pegasus | |
|---|---|
| Bayer |
|
| Flamsteed | |
| Variable | |
| HR |
|
| HD | |
| Gliese | |
| Other |
|