HD 191220
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| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 20h 24m 54.91771s[1] |
| Declination | −83° 18′ 38.2301″[1] |
| Apparent magnitude (V) | 6.14±0.01[2] |
| Characteristics | |
| Spectral type | A2/3 mA8-F0[3] |
| U−B color index | +0.13[4] |
| B−V color index | +0.20[4] |
| Astrometry | |
| Radial velocity (Rv) | 0.1±1.3[5] km/s |
| Proper motion (μ) | RA: +23.223 mas/yr[1] Dec.: +6.228 mas/yr[1] |
| Parallax (π) | 13.331±0.0247 mas[1] |
| Distance | 244.7 ± 0.5 ly (75.0 ± 0.1 pc) |
| Absolute magnitude (MV) | +1.76[6] |
| Details | |
| Mass | 2.06±0.40[7] M☉ |
| Radius | 2.17±0.06[8] R☉ |
| Luminosity | 15.57[9] L☉ |
| Surface gravity (log g) | 4.12±0.06[10] cgs |
| Temperature | 7,706±126[11] K |
| Metallicity [Fe/H] | −0.02[12] dex |
| Age | 979±166[1] Myr |
| Other designations | |
| 45 G. Octantis[13], CD−83°253, CPD−83°695, GC 28176, HD 191220, HIP 100697, HR 7698, SAO 258856[14] | |
| Database references | |
| SIMBAD | data |
HD 191220, also known as HR 7698, is a solitary white hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.14,[2] placing it near the limit for naked eye visibility. The object is located relatively close at a distance of 245 light years based on Gaia DR3 parallax measurements[1] but is slowly receding with a heliocentric radial velocity of 0.1 km/s.[5] At its current distance, HD 191220's brightness is diminished by 0.22 magnitudes due to interstellar dust.[15]
This is a chemically peculiar Am star[16] with a stellar classification of A2/3mA8-F0,[3] an A-type star with the metallic lines of a star with a class of A8-F0. It has double the mass of the Sun and 2.2 times its girth.[7] It radiates 15.57 times the luminosity of the Sun[9] from its photosphere at an effective temperature of 7,706 K.[11] HD 191220 is estimated to be nearly a billion years old[12] and has a near solar metallicity — what astronomers dub a star's abundance of chemical elements heavier than helium.[12]
