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 | |
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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 | |
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Bayer |
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Flamsteed | |
Variable | |
HR |
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HD | |
Gliese | |
Other |
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