Astronomy:BH Virginis

From HandWiki
Short description: Eclipsing binary star in the constellation Virgo
BH Virginis
BHVirLightCurve.png
A light curve for BH Virginis, plotted from TESS data[1]
Observation data
Equinox J2000.0]] (ICRS)
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[2] mas/yr
Dec.: −5.742[2] mas/yr
Parallax (π)6.6834 ± 0.0181[2] mas
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]

References

  1. MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 8 December 2021. 
  2. 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 Samus, N. N. et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  4. 4.0 4.1 4.2 4.3 4.4 Abt, Helmut A. (October 1965), "Spectrographic Measures of the Eclipsing System BH Virginis", Publications of the Astronomical Society of the Pacific 77 (458): 367, doi:10.1086/128233, Bibcode1965PASP...77..367A. 
  5. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331–346, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  6. 6.0 6.1 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, doi:10.1111/j.1365-2966.2004.07588.x, Bibcode2004MNRAS.349.1069K. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 7.6 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, doi:10.1051/0004-6361:20035902, Bibcode2004A&A...424..993K. 
  8. 8.0 8.1 8.2 8.3 8.4 8.5 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, doi:10.1051/aas:1997367, Bibcode1997A&AS..124..499C. 
  9. 9.0 9.1 9.2 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, doi:10.1093/pasj/59.5.955, Bibcode2007PASJ...59..955X. 
  10. "BH Vir". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BH+Vir. 
  11. Hoffmeister, Cuno (June 1935), "162 neue Veräderliche", Astronomische Nachrichten 255 (22): 401, doi:10.1002/asna.19352552202, Bibcode1935AN....255..401H.  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, Bibcode1957PASJ....9..191K. 
  13. Koch, Robert H. (April 1967), "The complicated eclipsing binary, BH Virginis", Astronomical Journal 72: 411, doi:10.1086/110243, Bibcode1967AJ.....72..411K. 
  14. Hoffmann, M. (March 1982), "The variable light curve of BH Vir", Astronomy and Astrophysics Supplement Series 47: 561–568, Bibcode1982A&AS...47..561H. 
  15. 15.0 15.1 Avvakumova, E. A. et al. (October 2013), "Eclipsing variables: Catalogue and classification", Astronomische Nachrichten 334 (8): 860, doi:10.1002/asna.201311942, Bibcode2013AN....334..860A. 
  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, doi:10.1093/pasj/60.3.571, Bibcode2008PASJ...60..571T. 

Further reading