Theta Virginis
Theta Virginis (θ Vir, θ Virginis) is a multiple star system in the zodiac constellation of Virgo. Based upon parallax measurements, it is about 320 light years from the Sun. The three stars in this system have a combined apparent visual magnitude of 4.37, bright enough to be seen with the naked eye.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 09m 56.99067s |
| Declination | −05° 32′ 20.4185″ |
| Apparent magnitude (V) | 4.37 (4.49 + 6.83 + 9.4 + 10.4) |
| Characteristics | |
| Spectral type | A1Vs + ? + A9m + ? |
| U−B color index | +0.00 |
| B−V color index | −0.02 |
| Astrometry | |
| Radial velocity (Rv) | −2.9 km/s |
| Proper motion (μ) | RA: −36.28 mas/yr Dec.: −31.22 mas/yr |
| Parallax (π) | 10.33 ± 1.09 mas |
| Distance | approx. 320 ly (approx. 100 pc) |
| Absolute magnitude (MV) | −0.52 |
| Details | |
| θ Vir Aa | |
| Mass | 3.11±0.11 M☉ |
| Luminosity | 190 L☉ |
| Surface gravity (log g) | 3.4 cgs |
| Temperature | 9,250 K |
| Rotational velocity (v sin i) | 4±1 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
The primary component, Theta Virginis Aa, is a white-hued A-type main sequence star with a stellar classification of A1Vs. It is part of a spectroscopic binary whose components, Aa and Ab, have visual magnitudes of +4.49 and +6.83 respectively. The system has an orbital period of about 33.04 years with an eccentricity of 0.9. The brighter member of this pair shows photometric and radial velocity periodicities with a cycle time of 0.7 days, which may indicate its rotation period.
The inner pair is orbited by the 9.4 magnitude B component, at an angular separation of 7.1 arcseconds. A fourth component C, 69.6 arcseconds away, has an apparent magnitude of 10.4. However, component C is an optical companion: it is physically unrelated and only appears close in the sky.