Astronomy:RS Canum Venaticorum

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Short description: Binary star in the constellation Canes Venatici
RS Canum Venaticorum
RSCVnLightCurve.png
Visual band light curves for RS Canum Venaticorum, adapted from Rodonò et al. (1995)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Canes Venatici
Right ascension  13h 10m 36.908s[2]
Declination +35° 56′ 05.58″[2]
Apparent magnitude (V) 7.93[3] to 9.14 (secondary: 8.19)[4]
Characteristics
A
Evolutionary stage Main-sequence[5]
Spectral type F6IV[6] or F5V[5]
B−V color index 0.46[7]
B
Evolutionary stage Subgiant[5]
Spectral type G8IV[6] or K2IV[5]
B−V color index 0.91[7]
Variable type Algol and RS CVn[4]
Astrometry
Radial velocity (Rv)−13.62±0.44[8] km/s
Proper motion (μ) RA: −49.898[2] mas/yr
Dec.: +20.754[2] mas/yr
Parallax (π)7.3486 ± 0.0225[2] mas
Distance444 ± 1 ly
(136.1 ± 0.4 pc)
Absolute magnitude (MV)2.95[9]
Orbit[10]
Period (P)4.797695 d
Eccentricity (e)0.00[1]
Inclination (i)85.55°
Periastron epoch (T)2,448,379.1993 HJD
Semi-amplitude (K1)
(primary)		90.2±0.1 km/s
Semi-amplitude (K2)
(secondary)		84.3 km/s
Details[10]
A
Mass1.44[7] M☉
Radius2.1 R☉
Temperature6,800 K
Rotation8.542 d
Rotational velocity (v sin i)11±2 km/s
Age2.5 Gyr
B
Mass1.31[7] M☉
Radius4.3 R☉
Temperature4,580 K
Rotational velocity (v sin i)42±3 km/s
Other designations
RS CVn, BD−36°2344, GJ 9430, HD 114519, HIP 64293, SAO 63382, WDS J13106+3556[11]
Database references
SIMBADdata

RS Canum Venaticorum is a binary star system in the northern constellation of Canes Venatici. It serves as the prototype to the class of RS Canum Venaticorum variables. The peak apparent visual magnitude of this system is below the level needed to observe it with the naked eye. It is located at a distance of approximately 443 light years from the Sun based on parallax,[2] but is drifting closer with a net radial velocity of −14 km/s.[8] Olin J. Eggen (1991) included this system as a member of the IC 2391 supercluster,[7] but it was later excluded.[12]

Variability

The variable nature of RS Canum Venaticorum was discovered by the Russian astronomer Lidiya Tseraskaya in 1914.[13] It is a detached binary in a close, circular orbit with a period of 4.8 days.[10] The orbital plane is inclined by an angle of 85.55° to the line of sight from the Earth, causing this to be viewed from Earth as an eclipsing binary. Some of the brightness variations are caused by large spots on the surface of the star. Similar variable stars are known as RS Canum Venaticorum variables.[10]

Some RS Canum Venaticorum variables, including this star, also undergo eclipses. The primary eclipse minimum decreases the visual brightness of the system by 1.21 magnitudes, while the secondary minimum decreases it by 0.26 magnitudes.[3] The exact magnitudes vary somewhat due to the inherent variability of the secondary. The General Catalogue of Variable Stars lists magnitude 8.19 for the secondary minimum and 9.14 for the primary minimum.[4]

Components

The primary component is a relatively inactive F-type main-sequence star[5] with a stellar classification of F5V. It has 2.1 times the radius of the Sun with a projected rotational velocity of about 11 km/s. That rate is slower than expected if the rotation of the star were locked with its orbital period. It has an estimated age of 2.5 billion years.[5]

The secondary component is a magnetically active K-type subgiant star with a class of K2 IV.[5] It has 4.3 times the Sun's radius and a relatively high rotation rate with a projected rotational velocity of 42 km/s.[10] This rapid spin was likely driven by interaction with the primary, and it generates the surface magnetic activity that makes the star variable.[14] As with the Sun, it is undergoing differential rotation.[10]

Lower temperature starspots cover a significant fraction of the secondary's surface, causing light variation as the star rotates.[15] These are found at several active latitudes on the star below 70°, and appear to migrate at the rate of 0.1° per day.[10] The total amount of spots varies in intensity with a cycle of 19.7±1.9 years, ranging from 17% to 37% coverage of the surface.[1] The luminosity also varies slightly (0.01) due to proximity and reflection from the primary star.[5] X-ray emission has been detected from this star with a luminosity of 2.14×1031 erg s−1.[10] It has also been detected in the radio band.[16]

References

  1. ↑ 1.0 1.1 1.2 Rodono, M. et al. (September 1995), "Starspot evolution, activity cycle and orbital period variation of the prototype active binary RS Canum Venaticorum.", Astronomy and Astrophysics 301: 75, Bibcode: 1995A&A...301...75R 
  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. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 Malkov, O. Yu. et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics 446 (2): 785–789, doi:10.1051/0004-6361:20053137, Bibcode: 2006A&A...446..785M 
  4. ↑ 4.0 4.1 4.2 Samus', N. N. et al. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S 
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Messina, S. (March 2008), "Long-term magnetic activity in close binary systems. I. Patterns of color variations", Astronomy and Astrophysics 480 (2): 495–508, doi:10.1051/0004-6361:20078932, Bibcode: 2008A&A...480..495M 
  6. ↑ 6.0 6.1 Strassmeier, K. G.; Fekel, F. C. (1990), "The spectral classification of chromospherically active binary stars with composite spectra", Astronomy and Astrophysics 230: 389, Bibcode: 1990A&A...230..389S 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 Eggen, O. J. (December 1991), "The IC 2391 Supercluster", Astronomical Journal 102: 2028, doi:10.1086/116025, Bibcode: 1991AJ....102.2028E 
  8. ↑ 8.0 8.1 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, Bibcode: 2004MNRAS.349.1069K 
  9. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A 
  10. ↑ 10.0 10.1 10.2 10.3 10.4 10.5 10.6 10.7 Xiang, Yue et al. (March 2020), "The first Doppler imaging of the active binary prototype RS Canum Venaticorum", Monthly Notices of the Royal Astronomical Society 492 (3): 3647–3656, doi:10.1093/mnras/staa063, Bibcode: 2020MNRAS.492.3647X 
  11. ↑ "RS CVn". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=RS+CVn. 
  12. ↑ Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal 110: 2862, doi:10.1086/117734, Bibcode: 1995AJ....110.2862E 
  13. ↑ Sitterly, Bancroft Walker (1930), "The Eclipsing Variable RS Canum Venaticorum", Contributions from the Princeton University Observatory 11: 21−41, Bibcode: 1930CoPri..11...21S 
  14. ↑ Percy, John R. (May 24, 2007), Understanding Variable Stars, Cambridge University Press, p. 90, ISBN 9781139463287, https://books.google.com/books?id=GQzCDQI3YP4C&pg=PA90 
  15. ↑ Eaton, Joel A. et al. (September 1993), "Spots on RS CVn From Spectroscopy and Photometry", Astronomical Journal 106: 1181, doi:10.1086/116717, Bibcode: 1993AJ....106.1181E 
  16. ↑ Boboltz, D. A. et al. (July 2003), "Astrometric Positions and Proper Motions of 19 Radio Stars", The Astronomical Journal 126 (1): 484–493, doi:10.1086/375462, Bibcode: 2003AJ....126..484B 

Further reading

  • Rodonò, M. et al. (May 2001), "On the determination of the light curve parameters of detached active binaries. I. The prototype RS Canum Venaticorum", Astronomy and Astrophysics 371: 174–185, doi:10.1051/0004-6361:20010324, Bibcode: 2001A&A...371..174R 
  • Heckert, Paul A.; Ordway, James I. (May 1995), "Long Term SPOT Activity on Eclipsing RS CVn Stars: RS CVn, SS Boo, and MM HER", Astronomical Journal 109: 2169, doi:10.1086/117442, Bibcode: 1995AJ....109.2169H 
  • Hall, D. S. (1994), "The active dynamo stars RS Cvn, BY Dra, FK Com, Algol, W UMa and T Tau.", Memorie della Societa Astronomica Italiana 65: 73–82, Bibcode: 1994MmSAI..65...73H 
  • Reglero, V.; Gimenez, A.; Estela, A. (May 1990), "The active eclipsing binary RS Canum Venaticorum", Astronomy and Astrophysics 231: 375–382, Bibcode: 1990A&A...231..375R 
  • Srivastava, J. B.; Kandpal, C. D. (January 1990), "UBV observations of RS canum venaticorum", Astrophysics and Space Science 163 (2): 217–222, doi:10.1007/BF00655742, Bibcode: 1990Ap&SS.163..217S 
  • Gimenez, A. et al. (July 1990), "Ultraviolet to near-infrared continuum flux distribution in the active binary RS canum venaticorum", Astrophysics and Space Science 169 (1–2): 233–236, doi:10.1007/BF00640721, Bibcode: 1990Ap&SS.169..233G 
  • Drake, Stephen A. et al. (December 1989), "A Survey of the Radio Continuum Emission of RS Canum Venaticorum and Related Active Binary Systems", Astrophysical Journal Supplement 71: 905, doi:10.1086/191402, Bibcode: 1989ApJS...71..905D 
  • Srivastava, R. K. (October 1987), "Photoelectric Observations and the Wave Minimum of Rs-Canum", Astrophysics and Space Science 137 (1): 63–72, doi:10.1007/BF00641619, Bibcode: 1987Ap&SS.137...63S 
  • Kang, Y. W.; Wilson, R. E. (June 1984), "Starspot Cycle of RS CVn", Bulletin of the American Astronomical Society 16: 726, Bibcode: 1984BAAS...16..726K 
  • Evren, S. et al. (January 1980), "New Light Curves of RS CVn", Information Bulletin on Variable Stars 1732: 1, Bibcode: 1980IBVS.1732....1E 
  • Eaton, J. A. et al. (November 1980), "A Sudden Acceleration in the Migration Rate of RS CVn", Information Bulletin on Variable Stars 1862: 1, Bibcode: 1980IBVS.1862....1E 
  • Naftilan, S. A.; Drake, S. A. (October 1980), "The spectrum of RS CVn.", Publications of the Astronomical Society of the Pacific 92: 675–681, doi:10.1086/130728, Bibcode: 1980PASP...92..675N 
  • Pfeiffer, R. J. (August 1979), "Intrinsic linear polarization of the eclipsing binary RS Canum Venaticorum.", Astrophysical Journal 232: 181–189, doi:10.1086/157277, Bibcode: 1979ApJ...232..181P 
  • Rhombs, C. G.; Fix, J. D. (September 1977), "Spectrophotometry of RS Canum Venaticorum, AR Lacertae, and UX Arietis.", Astrophysical Journal 216: 503–507, doi:10.1086/155491, Bibcode: 1977ApJ...216..503R 
  • Rhombs, C. G.; Fix, J. D. (1976), "A spectrophotometric investigation of the wave of RS CVn.", Acta Astronautica 26: 301–304, Bibcode: 1976AcA....26..301R 
  • Oliver, J. P. (October 1975), "Comments on the tilted ring model for the eclipsing binary RS CVn", Publications of the Astronomical Society of the Pacific 87: 695–697, doi:10.1086/129829, Bibcode: 1975PASP...87..695O 
  • Catalano, S.; Rodonò, M. (August 1974), "On the Orbital Period and Light Curve Variations of the Binary System RS Canum Venaticorum", Publications of the Astronomical Society of the Pacific 86 (512): 390, doi:10.1086/129620, Bibcode: 1974PASP...86..390C 
  • Arnold, C. N.; Hall, D. S. (October 1973), "On the Period Variations in RS CVn and SS Cam", Information Bulletin on Variable Stars 843: 1, Bibcode: 1973IBVS..843....1A 
  • Hall, Douglas S. (April 1972), "A T Tauri-Like Star in the Eclipsing Binary RS Canum Venaticorum", Publications of the Astronomical Society of the Pacific 84 (498): 323, doi:10.1086/129291, Bibcode: 1972PASP...84..323H 
  • Nelson, Burt; Duckworth, Edwin (October 1968), "Variations in the Light Curves of RS Canum Venticorum and SV Camelopardalis", Publications of the Astronomical Society of the Pacific 80 (476): 562, doi:10.1086/128686, Bibcode: 1968PASP...80..562N 
  • Popper, Daniel M. (January 1961), "Rediscussion of Eclipsing Binaries. V. RS Canum Venaticorum", Astrophysical Journal 133: 148, doi:10.1086/147011, Bibcode: 1961ApJ...133..148P 
  • Plavec, M.; Smetanová, M. (1959), "Period variations of the eclipsing binary RS Canum Venaticorum", Bulletin of the Astronomical Institute of Czechoslovakia 10: 192, Bibcode: 1959BAICz..10..192P 
  • Keller, G.; Limber, D. N. (May 1951), "A Photoelectric Study of the Eclipsing Stars RS Canum Venaticorum and YY Sagittarii", Astrophysical Journal 113: 637, doi:10.1086/145433, Bibcode: 1951ApJ...113..637K 
  • Joy, A. H. (July 1930), "The spectrographic orbit of RS Canum Venaticorum", Astrophysical Journal 72: 41–45, doi:10.1086/143258, Bibcode: 1930ApJ....72...41J 
  • Schilt, J. (March 1927), "The short-period variable star RV Canum Venaticorum", Astrophysical Journal 65: 124–129, doi:10.1086/143030, Bibcode: 1927ApJ....65..124S 
  • Joy, A. H. (August 1922), "Spectroscopic Observations of R S Canum Venaticorum", Publications of the Astronomical Society of the Pacific 34 (200): 221, doi:10.1086/123207, Bibcode: 1922PASP...34..221J 
  • Sitterly, B. W. (January 1921), "Provisional elements of the eclipsing system RS Canum Venaticorum", Astrophysical Journal 53: 99–104, doi:10.1086/142586, Bibcode: 1921ApJ....53...99S 




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