NY Virginis
NY Virginis is a binary star about 1,940 light-years away. The primary belongs to the rare class of subdwarf B stars, being former red giants with their hydrogen envelope completely stripped by a stellar companion. The companion is a red dwarf star. The binary nature of NY Virginis was first identified in 1998, and the extremely short orbital period of 0.101016 d, together with brightness variability on the timescale of 200 seconds was noticed, resulting in the identification of the primary star as a B-type subdwarf in 2003. Under a proposed classification scheme for hot subdwarfs it would be class sdB1VII:He1. This non-standard system indicates that it is a "normal" luminosity for a hot subdwarf and that the spectrum is dominated by hydrogen rather than helium.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 38m 48.14669s |
| Declination | −02° 01′ 49.2073″ |
| Apparent magnitude (V) | 13.30 - 14.22 |
| Characteristics | |
| Spectral type | sdB + M5 |
| Variable type | EA + RPHS |
| Astrometry | |
| Radial velocity (Rv) | −25.0 km/s |
| Proper motion (μ) | RA: −6.145±0.054 mas/yr Dec.: −12.054±0.025 mas/yr |
| Parallax (π) | 1.6801 ± 0.0376 mas |
| Distance | 1,940 ± 40 ly (600 ± 10 pc) |
| Absolute magnitude (MV) | 4.49 |
| Orbit | |
| Primary | NY Virginis A |
| Companion | NY Virginis B |
| Period (P) | 0.101015968166 d |
| Semi-major axis (a) | 0.0160 AU |
| Eccentricity (e) | 0.46 |
| Details | |
| NY Virginis A | |
| Mass | 0.459±0.005 M☉ |
| Radius | 0.151±0.001 R☉ |
| Luminosity | 23.3±1.5 L☉ |
| Surface gravity (log g) | 5.739±0.002 cgs |
| Temperature | 32,740±400 K |
| Rotation | 2.42438 hours |
| NY Virginis B | |
| Mass | 0.122 M☉ |
| Radius | 0.16 R☉ |
| Surface gravity (log g) | 5.14 cgs |
| Temperature | 3,000 K |
| Other designations | |
| Database references | |
| SIMBAD | data |