  | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 34m 07.93186s[1] |
| Declination | +03° 39′ 32.2738″[1] |
| Apparent magnitude (V) | 4.92[2] |
| Characteristics | |
| Spectral type | ApEuCrSr[3] |
| B−Vcolor index | 0.029±0.016[2] |
| Variable type | α2 CVn[4] |
| Astrometry | |
| Radial velocity (Rv) | −9.7±0.3[2] km/s |
| Proper motion (μ) | RA: +45.51[1]mas/yr Dec.: −24.70[1]mas/yr |
| Parallax (π) | 17.65±0.20 mas[1] |
| Distance | 185 ± 2 ly (56.7 ± 0.6 pc) |
| Absolute magnitude (MV) | 1.15[2] |
| Details[5] | |
| Mass | 2.16±0.04 M☉ |
| Radius | 2.11±0.04 R☉ |
| Luminosity | 27±2 L☉ |
| Temperature | 9,100±190 K |
| Rotational velocity (v sin i) | 29±4 km/s |
| Age | 435±55 Myr |
| Other designations | |
| o Vir,78 Vir,CW Virginis,BD+04°2764,FK5 1351,HD 118022,HIP 66200,HR 5105,SAO 120004[6] | |
| Database references | |
| SIMBAD | data |
78 Virginis is avariable star in thezodiacconstellation ofVirgo, located 175 light-years from the Sun. It has thevariable star designationCW Virginis and theBayer designationo Virginis;78 Virginis is theFlamsteed designation. This object is visible to thenaked eye as a faint, white-hued star with anapparent visual magnitude of 4.92. It is moving closer to the Earth with a heliocentricradial velocity of −10 km/s.[2]
This is anAp star with astellar classification of ApEuCrSr,[3] displaying stronglines of strontium, chromium, and otheriron peak elements.[5] In 1967, Kazimierz Stepień discovered that the star's brightness varies.[8] It is classified as anAlpha2 Canum Venaticorum variable, ranging in magnitude from 4.91 down to 4.99 with a period of 3.722 days.[4] 78 Virginis is the first star other than the Sun to have amagnetic field detected; it displays a dipole structure with a surface intensity of around3.3 kG. It is a candidaterapidly oscillating Ap (roAp) star. This star is 435 million years old with 2.16 times themass of the Sun and 2.11 times theSun's radius. It is radiating 27 times theSun's luminosity from itsphotosphere at aneffective temperature of 9,100 K.[5]
