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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
SIMBAD data

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]

References

  1. ^ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.
  2. ^ a b c d e 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. ^ a b c 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. ^ a b c d e 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. ^ a b 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. ^ a b c d e f g 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. ^ a b c d e f 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. ^ a b c 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. ^ a b 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