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.[8] The binary nature of NY Virginis was first identified in 1998,[9] 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.[10] 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.[11]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Virgo |
Right ascension | 13h 38m 48.14669s[2] |
Declination | −02° 01′ 49.2073″[2] |
Apparent magnitude (V) | 13.30 - 14.22[3] |
Characteristics | |
Spectral type | sdB + M5[4] |
Variable type | EA + RPHS[3] |
Astrometry | |
Radial velocity (Rv) | −25.0[5] km/s |
Proper motion (μ) | RA: −6.145±0.054 mas/yr[2] Dec.: −12.054±0.025 mas/yr[2] |
Parallax (π) | 1.6801 ± 0.0376 mas[2] |
Distance | 1,940 ± 40 ly (600 ± 10 pc) |
Absolute magnitude (MV) | 4.49[6] |
Orbit[7] | |
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[6] M☉ |
Radius | 0.151±0.001[6] R☉ |
Luminosity | 23.3±1.5[6] L☉ |
Surface gravity (log g) | 5.739±0.002[6] cgs |
Temperature | 32,740±400[6] K |
Rotation | 2.42438 hours[6] |
NY Virginis B | |
Mass | 0.122[8] M☉ |
Radius | 0.16[8] R☉ |
Surface gravity (log g) | 5.14[8] cgs |
Temperature | 3,000[8] K |
Other designations | |
Database references | |
SIMBAD | data |
In 2011, variations in the timing of the binary star's eclipses were used to infer the presence of a superjovian planet, NY Virginis (AB) b, on a wide orbit, with a second planet being suspected.[12] A study in 2014 found that a two-planet model was preferred. The orbits of these two planets are near or at a 3:10 mutual orbital resonance.[7] Another two-planet model with significant orbital eccentricity, updated to account for changes in eclipse timing not predicted by previous models, was published in 2019.[4]
Studies in 2022 have noted that since planetary models generally fail to predict subsequent changes in eclipse timing,[13] and the most recent two-planet model as of 2021 results in orbits that are unstable on an astronomically-short timescale,[14][15] a different explanation for the eclipse timing variations may be needed.
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b (controversial) | >2.7 MJ | 3.3 | 3160 | 0.15 | — | — |
c (controversial) | >5.5 MJ | 7.54 | 9861.75 | 0.15 | — | — |