BH Virginis

BH Virginis

A light curve for BH Virginis, plotted from TESS data
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Virgo
Right ascension 13h 58m 24.860s
Declination −01° 39′ 38.95″
Apparent magnitude (V) 9.60 - 10.56
Characteristics
Evolutionary stage Main sequence
Spectral type G0 V + G2 V
B−V color index 0.650±0.043
Variable type Algol + RS CVn
Astrometry
Radial velocity (Rv)−22.80±2.7 km/s
Proper motion (μ) RA: 2.672 mas/yr
Dec.: −5.742 mas/yr
Parallax (π)6.6834±0.0181 mas
Distance488 ± 1 ly
(149.6 ± 0.4 pc)
Orbit
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°
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 M☉
Radius1.22±0.05 R☉
Luminosity2.19 L☉
Surface gravity (log g)4.30 cgs
Temperature5,969±11 K
Metallicity [Fe/H]+0.1 dex
Component 2
Mass1.046±0.005 M☉
Radius1.11±0.04 R☉
Luminosity1.20 L☉
Surface gravity (log g)4.35 cgs
Temperature5,500 K
Metallicity [Fe/H]−0.3 dex
Other designations
BH Vir, BD−00°2769, HD 121909, HIP 68258, PPM 179196
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, 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. The system is drifting closer with a net radial velocity of −23 km/s.

This system was determined to be a short period variable star by C. Hoffmeister in 1935. 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. R. H. Koch in 1967 reported observing a change in the depth of the primary eclipse. In 1982, M. Hoffmann concluded that both stars are intrinsically variable, indicating this is an RS Canum Venaticorum variable system.

This is a near-contact binary system with a circular orbit having a period of 19.61 hours. The orbital plane is inclined at an angle of 88° to the line of sight from the Earth, allowing both components to eclipse each other once per orbit. During the deep primary eclipse the system decreases in brightness by 0.96 magnitude, while the shallower secondary eclipse decreases the system by 0.64 magnitude. 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.

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

References

  1. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.
  2. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. 1 2 3 Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  4. 1 2 3 4 5 Abt, Helmut A. (October 1965), "Spectrographic Measures of the Eclipsing System BH Virginis", Publications of the Astronomical Society of the Pacific, 77 (458): 367, Bibcode:1965PASP...77..367A, doi:10.1086/128233, S2CID 121053195.
  5. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331–346, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  6. 1 2 Karataș, Yüksel; et al. (2004), "Kinematics of chromospherically active binaries and evidence of an orbital period decrease in binary evolution", Monthly Notices of the Royal Astronomical Society, 349 (3): 1069–1092, arXiv:astro-ph/0404219, Bibcode:2004MNRAS.349.1069K, doi:10.1111/j.1365-2966.2004.07588.x, S2CID 15290475.
  7. 1 2 3 4 5 6 7 Kjurkchieva, D. P.; et al. (September 2004), "Spectroscopic and photometric observations of the short-period RS CVn-type star BH Virginis", Astronomy and Astrophysics, 424 (3): 993–1002, Bibcode:2004A&A...424..993K, doi:10.1051/0004-6361:20035902.
  8. 1 2 3 4 5 6 Clement, R.; et al. (September 1997), "Absolute parameters for binary systems. I. The active binary BH Virginis", Astronomy and Astrophysics Supplement Series, 124 (3): 499–508, Bibcode:1997A&AS..124..499C, doi:10.1051/aas:1997367.
  9. 1 2 3 Xiang, Fuyuan; et al. (October 2007), "Evidence of Hot Spot Activity on BH Virginis", Publications of the Astronomical Society of Japan, 59 (5): 955–960, Bibcode:2007PASJ...59..955X, doi:10.1093/pasj/59.5.955.
  10. ↑ "BH Vir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-06-10.
  11. ↑ Hoffmeister, Cuno (June 1935), "162 neue Veräderliche", Astronomische Nachrichten, 255 (22): 401, Bibcode:1935AN....255..401H, doi:10.1002/asna.19352552202. Listed as "– 0 2769" then "HD 121909" in a footnote.
  12. ↑ Kitamura, M.; et al. (1957), "A Photoelectric Study of the Eclipsing System BH Virginis", Publications of the Astronomical Society of Japan, 9: 191, Bibcode:1957PASJ....9..191K.
  13. ↑ Koch, Robert H. (April 1967), "The complicated eclipsing binary, BH Virginis", Astronomical Journal, 72: 411, Bibcode:1967AJ.....72..411K, doi:10.1086/110243.
  14. ↑ Hoffmann, M. (March 1982), "The variable light curve of BH Vir", Astronomy and Astrophysics Supplement Series, 47: 561–568, Bibcode:1982A&AS...47..561H.
  15. 1 2 Avvakumova, E. A.; et al. (October 2013), "Eclipsing variables: Catalogue and classification", Astronomische Nachrichten, 334 (8): 860, Bibcode:2013AN....334..860A, doi:10.1002/asna.201311942, hdl:10995/27061.
  16. ↑ Tian, Yong-Po; et al. (June 2008), "On the Period Variations of BH Virginis", Publications of the Astronomical Society of Japan, 60 (3): 571–575, Bibcode:2008PASJ...60..571T, doi:10.1093/pasj/60.3.571.

Further reading