HP Lyrae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 21m 39.066s |
| Declination | +39° 56′ 08.05″ |
| Apparent magnitude (V) | 10.43 (10.2 - 10.8) |
| Characteristics | |
| Spectral type | A2-F2 Iab |
| U−B color index | +0.1 - +0.5 |
| B−V color index | +0.3 - +0.7 |
| Variable type | RV Tau |
| Astrometry | |
| Radial velocity (Rv) | −107 km/s |
| Proper motion (μ) | RA: −2.485±0.038 mas/yr Dec.: −5.500±0.047 mas/yr |
| Parallax (π) | 0.0822±0.0242 mas |
| Distance | 6,700±380 pc |
| Absolute magnitude (MV) | −4.5 |
| Orbit | |
| Period (P) | 1,631 days |
| Eccentricity (e) | 0.17 |
| Argument of periastron (ω) (secondary) | 5.5° |
| Semi-amplitude (K1) (primary) | 7.7 km/s |
| Details | |
| Mass | 0.6 M☉ |
| Radius | 60 R☉ |
| Luminosity | 3,900±400 L☉ |
| Surface gravity (log g) | 1.0 cgs |
| Temperature | 5,900 K |
| Metallicity [Fe/H] | −1.0 dex |
| B | |
| Mass | 0.5 - 0.6 M☉ |
| Other designations | |
| HP Lyrae, TYC 3138-54-1, ASAS J192139+3956.1, IRAS 19199+3950, 2MASS J19213906+3956080, AAVSO 1918+39 | |
| Database references | |
| SIMBAD | data |
HP Lyrae (HP Lyr) is a variable star in the constellation Lyra, with a visual magnitude varying between 10.2 and 10.8. It will likely be an RV Tauri variable, an unstable post-AGB star losing mass before becoming a white dwarf.