DT Virginis
DT Virginis, also known as Ross 458, is a binary star system in the constellation of Virgo. It has an apparent visual magnitude of 9.79 and is located at a distance of 37.6 light-years from the Sun. Both of the stars are low-mass red dwarfs with at least one of them being a flare star. This binary system has a circumbinary sub-stellar companion.
Image of DT Virginis with the legacy surveys. The companion is the red object marked with an crosshair in the lower right. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 00m 46.557s |
| Declination | +12° 22′ 32.677″ |
| Apparent magnitude (V) | 9.79 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | M0.5 + M7.0 |
| U−B color index | 1.12 |
| B−V color index | 1.44 |
| Astrometry | |
| Radial velocity (Rv) | −12.33±0.32 km/s |
| Proper motion (μ) | RA: −628.7±0.184 mas/yr Dec.: −33.5±0.133 mas/yr |
| Parallax (π) | 86.9010 ± 0.1170 mas |
| Distance | 37.53 ± 0.05 ly (11.51 ± 0.02 pc) |
| Orbit | |
| Period (P) | 13.63±0.03 yr |
| Semi-major axis (a) | 4.93±0.01 AU |
| Eccentricity (e) | 0.245±0.001 |
| Inclination (i) | 130.3±0.3° |
| Longitude of the node (Ω) | 56.25±0.17° |
| Periastron epoch (T) | 2007.67±0.02 |
| Argument of periastron (ω) (secondary) | 157.5±0.6° |
| Details | |
| Primary (A) | |
| Mass | 0.553±0.007 M☉ |
| Radius | 0.473±0.021 R☉ 0.368±0.031 R☉ |
| Luminosity | 0.044+0.016 −0.012 L☉ |
| Temperature | 3,484±50 K |
| Metallicity [Fe/H] | 0.09±0.10 dex |
| Rotation | 2.89 d |
| Rotational velocity (v sin i) | 9.6±0.9 km/s |
| Age | 400–800 Myr |
| Secondary (B) | |
| Mass | 0.090±0.005 M☉ |
| Mass | 88.918+1.836 −2.844 MJup |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
This star was mentioned as a suspected variable by M. Petit in 1957. In 1960, O. J. Eggen classified it as a member of the Hyades moving group based on the system's space motion; it is now considered a likely member of the Carina Near Moving Group. Two flares were reported from this star in 1969 by N. I. Shakhovskaya, confirming it as a flare star. It was identified as an astrometric binary in 1994 by W. D. Heintz, who found a period of 14.5 years. The pair were resolved using adaptive optics in 1999. Early mass estimates placed the companion near the substellar limit, and it was initially proposed as a brown dwarf but is now considered late-type red dwarf.
The primary member, component A, is an M-type main-sequence star with a stellar classification of M0.5. It is young, magnetically very active star with a high rate of rotation and strong Hα emission. The star experiences star spots that cover 10–15% of the surface It is smaller and less massive than the Sun. The star is radiating just 4.4% of the luminosity of the Sun from its photosphere at an effective temperature of 3,484 K.