HD 17156
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cassiopeia |
| Right ascension | 02h 49m 44.48710s |
| Declination | +71° 45′ 11.6292″ |
| Apparent magnitude (V) | 8.16 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | F9V |
| Astrometry | |
| Radial velocity (Rv) | −3.15±0.20 km/s |
| Proper motion (μ) | RA: +90.848 mas/yr Dec.: −33.013 mas/yr |
| Parallax (π) | 12.9142±0.0177 mas |
| Distance | 252.6 ± 0.3 ly (77.4 ± 0.1 pc) |
| Absolute magnitude (MV) | 3.80 |
| Details | |
| Mass | 1.275±0.018 M☉ |
| Radius | 1.5007±0.0076 R☉ |
| Luminosity | 2.6 L☉ |
| Surface gravity (log g) | 4.17 cgs |
| Temperature | 6,079±80 K |
| Metallicity [Fe/H] | 0.24±0.05 dex |
| Age | 3.37+0.20 −0.47 Gyr |
| Other designations | |
| Nushagak, BD+71°171, HIP 13192, SAO 4737, GSC 04321-01320, PPM 5099, TYC 4321-1320-1, AG+71 95 | |
| Database references | |
| SIMBAD | data |
HD 17156, named Nushagak by the IAU, is a yellow subgiant star approximately 255 light-years away in the constellation of Cassiopeia. The apparent magnitude is 8.17, which means it is not visible to the naked eye but can be seen with good binoculars. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.
An extrasolar planet, HD 17156 b, was discovered with the radial velocity method in 2007, and subsequently was observed to transit the star. At the time it was the transiting planet with the longest period.