Phi Andromedae
Phi Andromedae (φ Andromedae, φ And) is the Bayer designation for a binary star system near the border of the northern constellation of Andromeda. This system has a combined apparent visual magnitude of 4.25 and is visible to the naked eye. Based upon parallax measurements made during the Hipparcos mission, this star system is located at a distance of about 720 light-years (220 parsecs) from Earth. With χ And it forms the Chinese asterism 軍南門 (Keun Nan Mun, Mandarin jūnnánmén), "the South Gate of the Camp".
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Right ascension | 01h 09m 30.12562s |
| Declination | +47° 14′ 30.4594″ |
| Apparent magnitude (V) | 4.25 (4.46/6.06) |
| Characteristics | |
| Spectral type | B7 Ve + B9 V |
| U−B color index | –0.34 |
| B−V color index | –0.07 |
| R−I color index | –0.05 |
| Astrometry | |
| Radial velocity (Rv) | –0.1 km/s |
| Proper motion (μ) | RA: +4.05 mas/yr Dec.: –12.43 mas/yr |
| Parallax (π) | 4.55 ± 0.60 mas |
| Distance | approx. 720 ly (approx. 220 pc) |
| Absolute magnitude (MV) | −2.41 |
| Orbit | |
| Companion | φ And B |
| Period (P) | 554.3 ± 67.1y yr |
| Semi-major axis (a) | 0.573 ± 0.051″ |
| Eccentricity (e) | 0.385 ± 0.043 |
| Inclination (i) | 142.2 ± 2.8° |
| Longitude of the node (Ω) | 337.2 ± 3.2° |
| Periastron epoch (T) | 17,740 ± 1,837 HMJD |
| Argument of periastron (ω) (secondary) | 112.6 ± 9.1° |
| Details | |
| φ And A | |
| Luminosity | 882 L☉ |
| Surface gravity (log g) | 3.150 cgs |
| Temperature | 13490 K |
| Rotational velocity (v sin i) | 75 km/s |
| Age | 63.1 ± 13.7 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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