OP Andromedae
OP Andromedae is a variable star in the constellation Andromeda. Varying between magnitudes 6.27 and 6.41 over 2.36 days, it has been classified as an RS Canum Venaticorum variable, but there has not been any proof of binarity, yet. It is a red giant star with a spectral classification of K1III.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 01h 36m 27.1998s |
| Declination | +48° 43′ 21.9998″} |
| Apparent magnitude (V) | 6.27 - 6.41 |
| Characteristics | |
| Spectral type | K1III |
| Apparent magnitude (J) | 3.794 |
| Apparent magnitude (H) | 3.165 |
| Apparent magnitude (K) | 2.914 |
| B−V color index | 1.2478 |
| Variable type | RS CVn |
| Astrometry | |
| Radial velocity (Rv) | −42.12±0.14 km/s |
| Proper motion (μ) | RA: −15.189±0.153 mas/yr Dec.: −17.663±0.148 mas/yr |
| Parallax (π) | 6.3462 ± 0.0912 mas |
| Distance | 514 ± 7 ly (158 ± 2 pc) |
| Absolute magnitude (MV) | 0.37 ± 0.23 |
| Details | |
| Mass | 1.5 – 3 M☉ |
| Radius | 16.1±2.2 R☉ |
| Luminosity | 128.825 L☉ |
| Surface gravity (log g) | 2.14 cgs |
| Temperature | 4,490 K |
| Metallicity [Fe/H] | -0.10 dex |
| Rotational velocity (v sin i) | 7.2 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
OP Andromedae is one of the few red giant stars where it was detected an overabundance of 7Li. The mechanism that enhances lithium in red giants is still unknown. It was proposed that those stars engulfed planets in the recent past; however, this theory was discarded since there is an overabundance of just one lithium isotope.
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