HAT-P-8
Magnitude 10 F-type star in the constellation Pegasus
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HAT-P-8 is a magnitude 10 star located 700 light-years away in Pegasus.[3] It is a F-type star about 28% more massive than the Sun.[4] Two red dwarf companions have been detected around HAT-P-8. The first has a spectral type of M5V and has a mass of 0.22 M☉. The second is even less massive, at 0.18 M☉, and its spectral type is M6V.[7]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pegasus[1] |
| Right ascension | 22h 52m 09.8636s[2] |
| Declination | +35° 26′ 49.608″[2] |
| Apparent magnitude (V) | 10.17[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F[4] |
| Apparent magnitude (B) | 10.77 ± 0.04[3] |
| Apparent magnitude (V) | 10.36 ± 0.03[3] |
| Apparent magnitude (J) | 9.214 ± 0.022[3] |
| Apparent magnitude (H) | 9.004 ± 0.018[3] |
| Apparent magnitude (K) | 8.953 ± 0.013[3] |
| Variable type | planetary transit[4] |
| Astrometry | |
| Radial velocity (Rv) | −22.2±0.3[2] km/s |
| Proper motion (μ) | RA: 74.676(19) mas/yr[2] Dec.: 14.944(20) mas/yr[2] |
| Parallax (π) | 4.6606±0.0208 mas[2] |
| Distance | 700 ± 3 ly (214.6 ± 1.0 pc) |
| Details | |
| Mass | 1.27±0.03[5] M☉ |
| Radius | 1.491+0.016 −0.014[5] R☉ |
| Luminosity | 3.0[2] L☉ |
| Surface gravity (log g) | 4.1956+0.0095 −0.013[5] cgs |
| Temperature | 6410±140[5] K |
| Metallicity [Fe/H] | -0.018+0.0072 −0.056[5] dex |
| Rotational velocity (v sin i) | 12.6 ± 1.0[6] km/s |
| Age | 3.4 ± 1 Gyr |
| Other designations | |
| TYC 2757-1152-1, GSC 02757-01152, 2MASS J22520985+3526495, Gaia DR3 1891507552826485632[3] | |
| Database references | |
| SIMBAD | data |
Planetary system
In 2008 the HATNet Project announced the discovery of extrasolar planet HAT-P-8b around this star. This planet is a hot Jupiter gas giant planet.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 1.354±0.035 MJ | 0.04496+0.00046 −0.00045 |
3.0763458±0.0000024 | <0.0060 | — | 1.334±0.013[5] RJ |
