HD 161988
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Apus |
| Right ascension | 17h 57m 41.686s |
| Declination | −76° 10′ 40.62″ |
| Apparent magnitude (V) | 6.07±0.01 |
| Characteristics | |
| Evolutionary stage | red giant branch |
| Spectral type | K2 III |
| U−B color index | +1.28 |
| B−V color index | +1.20 |
| Astrometry | |
| Radial velocity (Rv) | +36.8±0.4 km/s |
| Proper motion (μ) | RA: +2.464 mas/yr Dec.: −1.867 mas/yr |
| Parallax (π) | 5.2546±0.022 mas |
| Distance | 621 ± 3 ly (190.3 ± 0.8 pc) |
| Absolute magnitude (MV) | −0.26 |
| Details | |
| Mass | 3.05 M☉ |
| Radius | 20.8 R☉ |
| Luminosity | 185 L☉ |
| Surface gravity (log g) | 2.04±0.02 cgs |
| Temperature | 4,498 K |
| Metallicity [Fe/H] | −0.13 dex |
| Rotational velocity (v sin i) | 2.1±1.3 km/s |
| Other designations | |
| 63 G. Apodis, CD−76°919, CPD−76 1226, HD 161988, HIP 87926, HR 6635, SAO 257542, WDS J17577-7611A | |
| Database references | |
| SIMBAD | data |
HD 161988, also known as HR 6635, is a solitary, orange hued star located in the southern circumpolar constellation Apus. It has an apparent magnitude of 6.07, allowing it to be faintly visible to the naked eye. Parallax measurements place it at a distance of 621 light years, and it is currently receding with a heliocentric radial velocity of 36.8 km/s.
The object has a stellar classification of K2 III, indicating that it is a red giant. Gaia Data Release 3 models place it on the red giant branch. At present it has 3.05 times the mass of the Sun and an enlarged radius of 20.8 R☉. It shines at 185 times the luminosity of the Sun from its photosphere at an effective temperature of 4,498 K. HD 161988 has an iron abundance 74% that of the Sun, making it slightly metal deficient. Like most giants, it spins modestly with a projected rotational velocity of 2.1 km/s.
HD 161988 has a 14th magnitude optical companion located 26.4 arcseconds away along a position angle of 122°.