39 Andromedae
Double star in the constellation Andromeda
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39 Andromedae, abbreviated 39 And, is a double star in the northern constellation Andromeda. 39 Andromedae is the Flamsteed designation. Its apparent visual magnitude is 5.95,[1] which indicates it is near the lower limit on visibility to the naked eye. The distance to this star, as estimated from its annual parallax shift of 9.57 mas,[2] is 341 light years. It is a suspected member of the Ursa Major Moving Group, although King et al. (2003) list it as a probable non-member.[10]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda[1] |
| Right ascension | 01h 02m 54.25471s[2] |
| Declination | +41° 20′ 42.7688″[2] |
| Apparent magnitude (V) | 5.95[1] |
| Characteristics | |
| Spectral type | kA3hA7VmA9[3] |
| B−V color index | +0.161±0.009[1] |
| Astrometry | |
| Radial velocity (Rv) | +3.1±0.9[4] km/s |
| Proper motion (μ) | RA: −18.380[2] mas/yr Dec.: −18.498[2] mas/yr |
| Parallax (π) | 9.5651±0.1226 mas[2] |
| Distance | 341 ± 4 ly (105 ± 1 pc) |
| Absolute magnitude (MV) | 0.80[1] |
| Details | |
| Mass | 2.01[5] M☉ |
| Radius | 3.02[5] R☉ |
| Luminosity | 37[5] L☉ |
| Surface gravity (log g) | 3.78[5] cgs |
| Temperature | 8,203[5] K |
| Metallicity [Fe/H] | −0.01[6] dex |
| Rotation | 30.4 days[7] |
| Rotational velocity (v sin i) | 34[8] km/s |
| Age | 670[6] Myr |
| Other designations | |
| 39 And, BD+40°209, HD 6116, HIP 4903, HR 290, SAO 36874, PPM 43575, WDS J01029+4121A[9] | |
| Database references | |
| SIMBAD | data |
The brighter component is a confirmed Am star[11] with a stellar classification of kA3hA7VmA9.[3] This notation indicates its spectrum displays the calcium K line of an A3 star, the hydrogen lines of an A7 V, or A-type main-sequence star, and the metal lines of an A9 star. It is radiating 37 times the Sun's luminosity from its photosphere at an effective temperature of 8,203 K.[5] As of 2015, the magnitude 12.48 companion star is located at an angular separation of 20.5″ along a position angle of 3° from the primary.[12]