32 Virginis
Variable star in the constellation Virgo
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32 Virginis, also known as FM Virginis, is a star located about 250 light years from the Earth, in the constellation Virgo.[2] Its apparent magnitude ranges from 5.20 to 5.28, making it faintly visible to the naked eye of an observer well away from city lights.[3] 32 Virginis is a binary star,[11] and the more massive component of the binary is a Delta Scuti variable star which oscillates with a dominant period of 103.51 minutes.[11]
A light curve for FM Virginis, plotted from TESS data.[1] The 103.51 minute period is marked in red. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 12h 45m 37.05805s[2] |
| Declination | +07° 40′ 23.9689″[2] |
| Apparent magnitude (V) | 5.20 - 5.28[3] |
| Characteristics | |
| Spectral type | F0 IIIm (primary)[4] + A7V (secondary)[5] |
| U−B color index | +0.15 [6] |
| B−V color index | +0.33[6] |
| Variable type | Delta Scuti[3] |
| Astrometry | |
| Proper motion (μ) | RA: −107.527±0.697[2] mas/yr Dec.: 4.915±0.344[2] mas/yr |
| Parallax (π) | 12.8075±0.3062 mas[2] |
| Distance | 255 ± 6 ly (78 ± 2 pc) |
| Absolute magnitude (MV) | +1.75[5] |
| Orbit[7] | |
| Period (P) | 38.324 d |
| Eccentricity (e) | 0.074±0.006 |
| Periastron epoch (T) | 2434039.463±0.038 |
| Argument of periastron (ω) (primary) | 210.02±5.1° |
| Semi-amplitude (K1) (primary) | 48.05±0.33 km/s |
| Details | |
| primary (Delta Scuti variable) | |
| Mass | 2.05[5] M☉ |
| Surface gravity (log g) | 3.75[8] cgs |
| Temperature | 7,450[8] K |
| Rotational velocity (v sin i) | 24[8] km/s |
| secondary | |
| Mass | 1.9[5] M☉ |
| Rotational velocity (v sin i) | 140[8] km/s |
| Other designations | |
| FM Vir, d2 Virginis, HD 110951, BD+08 2639, HIP 62267, HR 4847, SAO 119574,[9] Boss 3323[10] | |
| Database references | |
| SIMBAD | data |
In 1914, Walter Sydney Adams announced that 32 Virginis is a spectroscopic binary.[12] John Beattie Cannon published the first set of orbital elements for the binary system in 1915.[13] Corrado Bartolini et al. made photometric observations of the star in early 1971, and found that the star showed variability due to pulsations.[14] In 1974, 32 Virginis was given the variable star designation FM Virginis.[15] Donald Kurtz et al. determined that the star was a Delta Scuti variable, in 1976.[8]
The primary star is believed to be an Am star similar to rho Puppis - a pulsating post-main sequence star.[16]