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	13^h 58^m 24.860^s[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]
Distance	488 ± 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
Mass	1.173±0.006[7] M☉
Radius	1.22±0.05[7] R☉
Luminosity	2.19[8] L☉
Surface gravity (log g)	4.30[8] cgs
Temperature	5,969±11[9] K
Metallicity [Fe/H]	+0.1[8] dex
Component 2
Mass	1.046±0.005[7] M☉
Radius	1.11±0.04[7] R☉
Luminosity	1.20[8] L☉
Surface gravity (log g)	4.35[8] cgs
Temperature	5,500[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. 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. 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. 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. 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. 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. 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. 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. 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

• Kozhevnikova, A. V.; et al. (November 2007), "Long-term starspot activity of the eclipsing binaries BH Vir and WY Cnc", Astronomy Reports, 51 (11): 932–946, Bibcode:2007ARep...51..932K, doi:10.1134/S1063772907110066, S2CID 120895929.
• Xiang, Fu Yuan; Zhou, Yi Chun (June 2004), "A Photometric Analysis and Spot Activity of BH Virginis", Publications of the Astronomical Society of Japan, 56 (3): 469–474, Bibcode:2004PASJ...56..469X, doi:10.1093/pasj/56.3.469.
• Xiang, F. Y.; Zhou, Y. C. (January 2004), "The spot activity of BH Virginis", New Astronomy, 9 (1): 27–31, Bibcode:2004NewA....9...27X, doi:10.1016/j.newast.2003.07.001.
• Arevalo, M. J.; et al. (January 2002), "J and K Infrared Light Curves of the Active Binary BH Vir", Information Bulletin on Variable Stars, 5222: 1, Bibcode:2002IBVS.5222....1A.
• Xiang, F. Y.; et al. (October 2000), "Star-spots activity on BH Virginis", Astronomy and Astrophysics Supplement Series, 146: 7–12, Bibcode:2000A&AS..146....7X, doi:10.1051/aas:2000260.
• Qian, Shengbang; et al. (2000), "Orbital Period Studies of RS CVn-type binaries III. BH Virginis", Astrophysics and Space Science, 274 (4): 859–866, Bibcode:2000Ap&SS.274..859Q, doi:10.1023/A:1026512806446, S2CID 189838086.
• Popper, Daniel M. (September 1997), "Orbits of detached main-sequence eclipsing binaries of types late F to K. II. UV leonis, UV piscium, and BH virginis", The Astronomical Journal, 114: 1195, Bibcode:1997AJ....114.1195P, doi:10.1086/118552.
• Xiang, F. Y.; Liu, Q. Y. (August 1997), "The variable light curve of BH Virginis", Astronomy and Astrophysics Supplement Series, 124 (2): 281–282, Bibcode:1997A&AS..124..281X, doi:10.1051/aas:1997191.
• Lazaro, C.; Arevalo, M. J. (June 1997), "Time-Resolved Spectroscopy of RS CVn Short-Period Systems. I. CG CYG, BH VIR, and ER VUL", Astronomical Journal, 113: 2283, Bibcode:1997AJ....113.2283L, doi:10.1086/118439.
• Clement, R.; et al. (May 1997), "Four colour photometry of late-type binary systems. II. New light curves of BH Virginis", Astronomy and Astrophysics Supplement Series, 123: 59–61, Bibcode:1997A&AS..123...59C, doi:10.1051/aas:1997343.
• Heckert, P. A.; Summers, D. L. (August 1995), "1994 photometry of BH Virginis", Information Bulletin on Variable Stars, 4225: 1, Bibcode:1995IBVS.4225....1H.
• Heckert, P. A.; Summers, D. L. (August 1994), "1993 BVRI Photometry of BH Virginis", Information Bulletin on Variable Stars, 4062: 1, Bibcode:1994IBVS.4062....1H.
• Zhai, D. S.; et al. (October 1990), "An analysis of basic parameters and SPOT activities of the solar-type binary system BH Virginis", Astronomy and Astrophysics, 237: 148, Bibcode:1990A&A...237..148Z.
• Arévalo, M. J.; Lázaro, C. (July 1990), "The Photometric Behaviour of BH Vir", Astrophysics and Space Science, 169 (1–2): 245–246, Bibcode:1990Ap&SS.169..245A, doi:10.1007/BF00640724, S2CID 124271181.
• Derman, E.; et al. (December 1989), "1989 Light Curves of BH Vir", Information Bulletin on Variable Stars, 3404: 1, Bibcode:1989IBVS.3404....1D.
• Zeilik, M.; et al. (May 1990), "Long-Term Starspot Activity of Short-Period RS Canum Venaticorum Stars. III. BH Virginis", Astrophysical Journal, 354: 352, Bibcode:1990ApJ...354..352Z, doi:10.1086/168693.
• Arevalo, M. J.; et al. (December 1987), "1986 BV Light Curves of BH Virginis", Information Bulletin on Variable Stars, 3117: 1, Bibcode:1987IBVS.3117....1A.
• Scaltriti, F.; et al. (August 1985), "Photometry of southern stars. II. Further evidence of spots in the eclipsing binary BH Virginis", Astronomy and Astrophysics, 149: 11–14, Bibcode:1985A&A...149...11S.
• Giuricin, G.; et al. (January 1984), "Lightcurve analysis for the eclipsing binaries ST Car, RY Ind and BH Vir", Monthly Notices of the Royal Astronomical Society, 206 (2): 305–313, Bibcode:1984MNRAS.206..305G, doi:10.1093/mnras/206.2.305.
• Botsula, R. A. (1978), "Instability in detached binary systems of the main sequence with solar-type components. II. BH Virginis", Peremennye Zvezdy (in Russian), 20: 577–587, Bibcode:1978PZ.....20..577B.
• Whitney, B. S. (1955), "Minima and periods of eclipsing stars", Astronomical Journal, 60: 453, Bibcode:1955AJ.....60..453W, doi:10.1086/107258.