R Andromedae
R Andromedae (R And) is a Mira-type variable star in the constellation Andromeda. Its spectral class is type S because it shows absorption bands of zirconium monoxide (ZrO) in its spectrum. It was among the stars found by Paul Merrill to show absorption lines of the unstable element technetium, establishing that nucleosynthesis must be occurring in stars. The SH molecule was found for the first time outside earth in the atmosphere of this star. The star is losing mass due to stellar winds at a rate of 1.09×10−6 M☉/yr.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 00h 24m 01.946s |
| Declination | +38° 34′ 37.37″ |
| Apparent magnitude (V) | 5.8 - 15.2 |
| Characteristics | |
| Spectral type | S3,5e-S8,8e(M7e) |
| B−V color index | 1.97 |
| Variable type | Mira |
| Astrometry | |
| Radial velocity (Rv) | −6.40 km/s |
| Proper motion (μ) | RA: −16.021±0.148 mas/yr Dec.: −32.794±0.141 mas/yr |
| Parallax (π) | 2.6444 ± 0.1600 mas |
| Distance | 1,230 ± 70 ly (380 ± 20 pc) |
| Absolute magnitude (MV) | −5.19 |
| Details | |
| Radius | 476±120 - 493±129 R☉ |
| Luminosity | 6,300 L☉ |
| Surface gravity (log g) | −1.02 cgs |
| Temperature | 2,500 K |
| Metallicity [Fe/H] | −1.01 dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
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