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Variable star in the constellation Virgo From Wikipedia, the free encyclopedia
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 | |
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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 | |
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]