BH Virginis

BH Virginis

A light curve for BH Virginis, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Virgo
Right ascension 13h 58m 24.860s[2]
Declination −01° 39′ 38.95″[2]
Apparent magnitude (V) 9.60 - 10.56[3]
Characteristics
Evolutionary stage Main sequence
Spectral type G0 V + G2 V[4]
B−V color index 0.650±0.043[5]
Variable type Algol + RS CVn[3]
Astrometry
Radial velocity (Rv)−22.80±2.7[6] km/s
Proper motion (μ) RA: 2.672 mas/yr[2]
Dec.: −5.742 mas/yr[2]
Parallax (π)6.6834 ± 0.0181 mas[2]
Distance488 ± 1 ly
(149.6 ± 0.4 pc)
Orbit[4]
Period (P)0.8169 d
Semi-major axis (a)≥1.55 Gm (2.23 R☉)
Eccentricity (e)0.0
Inclination (i)87.5±0.8[7]°
Periastron epoch (T)2,431,241.389±1.0 JD
Argument of periastron (ω)
(secondary)		0.0°
Semi-amplitude (K1)
(primary)		137.8 km/s
Semi-amplitude (K2)
(secondary)		135.2 km/s
Details
Component 1
Mass1.173±0.006[7] M☉
Radius1.22±0.05[7] R☉
Luminosity2.19[8] L☉
Surface gravity (log g)4.30[8] cgs
Temperature5,969±11[9] K
Metallicity [Fe/H]+0.1[8] dex
Component 2
Mass1.046±0.005[7] M☉
Radius1.11±0.04[7] R☉
Luminosity1.20[8] L☉
Surface gravity (log g)4.35[8] cgs
Temperature5,500[9] K
Metallicity [Fe/H]−0.3[8] dex
Other designations
BH Vir, BD−00°2769, HD 121909, HIP 68258, PPM 179196[10]
Database references
SIMBADdata

BH Virginis is a binary star system in the equatorial constellation of Virgo. With a typical apparent visual magnitude of 9.6,[3] it is too faint to be visible to the naked eye. Based on parallax measurements, it is located at a distance of approximately 488 light years from the Sun.[2] The system is drifting closer with a net radial velocity of −23 km/s.[6]

This system was determined to be a short period variable star by C. Hoffmeister in 1935.[11] W. Zessewitsch found a period of 19.6 hours for the system in 1944. In 1957, M. Kitamura and associates refined the light curve of this Algol-type eclipsing variable and discovered some irregular fluctuations not explained by the eclipse cycle.[12] R. H. Koch in 1967 reported observing a change in the depth of the primary eclipse.[13] In 1982, M. Hoffmann concluded that both stars are intrinsically variable, indicating this is an RS Canum Venaticorum variable system.[14]

This is a near-contact[15] binary system with a circular orbit having a period of 19.61 hours.[4] The orbital plane is inclined at an angle of 88° to the line of sight from the Earth,[7] allowing both components to eclipse each other once per orbit. During the deep[4] primary eclipse the system decreases in brightness by 0.96 magnitude, while the shallower secondary eclipse decreases the system by 0.64 magnitude.[15] Cyclical oscillations in the orbital period have been observed with two short-term periods of 9.2 and 11.8 years, and a longer-term oscillation of 51.7 years. The short term oscillations may be due to magnetic activity on the stars, while the longer period could be caused by an unseen third body.[16]

Both components of this system are G-type main-sequence stars, with stellar classifications of G0V and G2V, respectively.[4] Evidence of star spots have been found on both stars, but appear to be predominantly on the secondary component.[9] The two stars are somewhat larger and more massive than the Sun.[7]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference GaiaEDR3 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Samus_et_al_2017 was invoked but never defined (see the help page).
  4. ^ a b c d e Cite error: The named reference Abt1965 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Karataș_et_al_2004 was invoked but never defined (see the help page).
  7. ^ a b c d e f g Cite error: The named reference Kjurkchieva_et_al_2004 was invoked but never defined (see the help page).
  8. ^ a b c d e f Cite error: The named reference clement1997 was invoked but never defined (see the help page).
  9. ^ a b c Cite error: The named reference Xiang_et_al_2007 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Hoffmeister1935 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kitamura_et_al_1957 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Koch1967 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Hoffmann1982 was invoked but never defined (see the help page).
  15. ^ a b Cite error: The named reference Avvakumova_et_al_2013 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Tian_et_al_2008 was invoked but never defined (see the help page).