RS Canum Venaticorum

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RS Canum Venaticorum
RSCVnLightCurve.png
Visual band light curves for RS Canum Venaticorum, adapted from Rodonò et al. (1995) [1]
Observation data
Epoch J2000.0       Equinox J2000.0
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  mas/yr [2]
Dec.: +20.754  mas/yr [2]
Parallax (π)7.3486 ± 0.0225  mas [2]
Distance 444 ± 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
Mass 1.44 [7]   M☉
Radius 2.1  R☉
Temperature 6,800  K
Rotation 8.542 d
Rotational velocity (v sin i)11±2 km/s
Age 2.5  Gyr
B
Mass 1.31 [7]   M☉
Radius 4.3  R☉
Temperature 4,580  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
SIMBAD data

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]

Contents

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]

Related Research Articles

A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to the magnetic energy stored in the stars' atmospheres. The brightness increase is across the spectrum, from X-rays to radio waves. Flare activity among late-type stars was first reported by A. van Maanen in 1945, for WX UMa and YZ CMi. However, the best-known flare star is UV Ceti, first observed to flare in 1948. Today similar flare stars are classified as UV Ceti type variable stars in variable star catalogs such as the General Catalogue of Variable Stars.

<span class="mw-page-title-main">RS Canum Venaticorum variable</span>

An RS Canum Venaticorum variable is a type of variable star. The variable type consists of close binary stars having active chromospheres which can cause large stellar spots. These spots are believed to cause variations in their observed luminosity. Systems can exhibit variations on timescales of years due to variation in the spot surface coverage fraction, as well as periodic variations which are, in general, close to the orbital period of the binary system. Some systems exhibit variations in luminosity due to their being eclipsing binaries. Typical brightness fluctuation is around 0.2 magnitudes. They take their name from the star RS Canum Venaticorum.

<span class="mw-page-title-main">Epsilon Ursae Minoris</span> Binary star system in the constellation Ursa Minor

Epsilon Ursae Minoris is a binary star system in the northern circumpolar constellation of Ursa Minor. It is visible to the naked eye with a combined apparent visual magnitude of 4.19. Based upon an annual parallax shift of 10.73 mas as seen from the Earth, it is located around 300 light years from the Sun. The pair are drawing nearer to the Sun with a radial velocity of −10.57 km/s.

<span class="mw-page-title-main">Beta Canum Venaticorum</span> Star in constellation Canes Venatici

Beta Canum Venaticorum, also named Chara, is a G-type main-sequence star in the northern constellation of Canes Venatici. At an apparent visual magnitude of 4.25, it is the second-brightest star in the constellation. Based upon an annual parallax shift of 118 mas, this star is 27.6 light-years distant from the Sun.

21 Canum Venaticorum is a single variable star in the northern constellation of Canes Venatici, located 277 light years away from the Sun. This object has the variable star designation BK Canum Venaticorum; 21 Canum Venaticorum is the Flamsteed designation. It is visible to the naked eye as a faint white-hued star with a baseline apparent visual magnitude of +5.14.

<span class="mw-page-title-main">4 Canum Venaticorum</span> Binary star system in the constellation Canes Venatici

4 Canum Venaticorum is a binary star system in the northern constellation of Canes Venatici, located around 425 light years away. It has the variable star designation AI Canum Venaticorum; 4 Canum Venaticorum is its Flamsteed designation. Its brightness varies from magnitude +5.89 to +6.15 with a period of 2.8 hours, which places it around the lower limit of visibility to the naked eye. This was found to be a binary by Schmid et al. in 2014, based on periodic, non-sinusoidal changes in its radial velocity. It is a single-lined spectroscopic binary with an orbital period of 124.4 days and an eccentricity of 0.31.

<span class="mw-page-title-main">II Pegasi</span> Star in the constellation Pegasus

II Pegasi is a binary star system in the constellation of Pegasus with an apparent magnitude of 7.4 and a distance of 130 light-years. It is a very active RS Canum Venaticorum variable, a close binary system with active starspots.

<span class="mw-page-title-main">Omicron Draconis</span> Variable star in the constellation Draco

Omicron Draconis is a giant star in the constellation Draco located 322.93 light years from the Earth. Its path in the night sky is circumpolar for latitudes greater than 31o north, meaning the star never rises or sets when viewed in the night sky.

AM Canum Venaticorum is a hydrogen-deficient cataclysmic variable binary star in the constellation of Canes Venatici. It is the type star of its class of variables, the AM Canum Venaticorum stars. The system consists of a white dwarf gaining matter via an accretion disk from a semi-degenerate or white dwarf companion.

<span class="mw-page-title-main">HR 5110</span> Star in constellation Canes Venatici

HR 5110, also known as BH Canum Venaticorum, is a binary star system in the northern constellation of Canes Venatici. It is visible to the naked eye with an apparent visual magnitude of 4.91. Based upon an annual parallax shift of 21.90±0.23 mas, it is located 149 light-years away. The system is moving further from the Sun with a heliocentric radial velocity of 6.4 km/s.

<span class="mw-page-title-main">Sigma Coronae Borealis</span> Star in the constellation Corona Borealis

Sigma Coronae Borealis is a star system in the constellation of Corona Borealis. It is a quintuple star system containing three sunlike main-sequence stars and two other low-mass stars. The combined visual magnitude is 5.3 and the system lies 74 light years from Earth. σ CrB A is the variable star TZ Coronae Borealis.

<span class="mw-page-title-main">13 Ceti</span> Star in the constellation Cetus

13 Ceti is a triple star system in the equatorial constellation of Cetus. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.20. The system is located at a distance of approximately 69 light years from the Sun based on stellar parallax, and is drifting further away with a radial velocity of +10.4 km/s. It shares a common motion with the Hyades moving group, although it is too old to be a member.

<span class="mw-page-title-main">XY Ursae Majoris</span> Eclipsing binary star system in the constellation of Ursa Major

XY Ursae Majoris is a short period binary star system in the northern circumpolar constellation of Ursa Major. It is an eclipsing binary with a baseline apparent visual magnitude of 9.50. The system is located at a distance of 221.5 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10 km/s. It has a relatively high proper motion, traversing the celestial sphere at the angular rate of 0.191″·yr−1.

<span class="mw-page-title-main">SZ Piscium</span> Star system in the constellation Pisces

SZ Piscium is a suspected triple star system in the equatorial constellation of Pisces. The inner pair form a double-lined spectroscopic binary with an orbital period of 3.966 days. It is a detached Algol-type eclipsing binary of the RS Canum Venaticorum class with a subgiant component. The system is too faint to be readily visible to the naked eye with a combined apparent visual magnitude of 7.18. It is located at a distance of approximately 306 light years based on parallax measurements.

<span class="mw-page-title-main">BH Virginis</span> Eclipsing binary star in the constellation Virgo

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.

<span class="mw-page-title-main">UV Piscium</span> Binary star system in the Pisces constellation

UV Piscium is a binary star system in the constellation of Pisces. With a peak apparent visual magnitude of 8.98, it is too faint to be visible to the naked eye. This is an eclipsing binary system that decreases to magnitude 10.05 during the primary eclipse, then to magnitude 9.54 with the secondary eclipse. It is located at a distance of 232 light years from the Sun based on parallax measurements, and is receding with a radial velocity of 6.5 km/s. The position of this star near the ecliptic means it is subject to lunar occultation.

<span class="mw-page-title-main">ER Vulpeculae</span> Variable star in the constellation Vulpecula

ER Vulpeculae is a binary star system in the northern constellation of Vulpecula, abbreviated ER Vul. It is a variable star system with a brightness that ranges from an apparent visual magnitude of 7.27 down to 7.49, which is too faint to be visible to the naked eye. This system is located at a distance of 165 light years from the Sun based on parallax measurements. It is drifting closer with a radial velocity of −25 km/s.

<span class="mw-page-title-main">DM Ursae Majoris</span> Variable star in the constellation Ursa Major

DM Ursae Majoris is a binary star system in the northern circumpolar constellation of Ursa Major, abbreviated DM UMa. It is sometimes identified by the Bonner Durchmusterung catalogue designation BD +61 1211; DM UMa is the variable star designation. The system has a combined apparent visual magnitude of 9.29, which is too faint to be visible to the naked eye. Based on parallax measurements, the system is located at a distance of approximately 606 light years from the Sun, but it is drifting closer with a heliocentric radial velocity of −7 km/s.

<span class="mw-page-title-main">HR 1099</span> Triple star system in the constellation Taurus

HR 1099 is a triple star system in the equatorial constellation of Taurus, positioned 11′ to the north of the star 10 Tauri. This system has the variable star designation V711 Tauri, while HR 1099 is the star's identifier from the Bright Star Catalogue. It ranges in brightness from a combined apparent visual magnitude of 5.71 down to 5.94, which is bright enough to be dimly visible to the naked eye. The distance to this system is 96.6 light years based on parallax measurements, but it is drifting closer with a radial velocity of about −15 km/s.

<span class="mw-page-title-main">CR Boötis</span> Star system in the constellation Boötes

CR Boötis is an interacting binary system in the northern constellation of Boötes, abbreviated CR Boo. It is one of the best-known AM Canum Venaticorum stars. The system varies widely in brightness, ranging in apparent visual magnitude from 13.6 down to 17.5. The distance to this system is approximately 1,150 light years from the Sun, based on parallax measurements.

References

  1. 1 2 3 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. 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 Malkov, O. Yu.; et al. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics, 446 (2): 785–789, Bibcode:2006A&A...446..785M, doi: 10.1051/0004-6361:20053137
  4. 1 2 3 Samus', N. N.; et al. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   125853869
  5. 1 2 3 4 5 6 7 8 Messina, S. (March 2008), "Long-term magnetic activity in close binary systems. I. Patterns of color variations", Astronomy and Astrophysics, 480 (2): 495–508, arXiv: 0712.2117 , Bibcode:2008A&A...480..495M, doi:10.1051/0004-6361:20078932, S2CID   117824595
  6. 1 2 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. 1 2 3 4 5 Eggen, O. J. (December 1991), "The IC 2391 Supercluster", Astronomical Journal, 102: 2028, Bibcode:1991AJ....102.2028E, doi:10.1086/116025
  8. 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
  9. ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644
  10. 1 2 3 4 5 6 7 8 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, arXiv: 2001.02572 , Bibcode:2020MNRAS.492.3647X, doi:10.1093/mnras/staa063
  11. ↑ "RS CVn". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2020-11-05.
  12. ↑ Eggen, Olin J. (December 1995), "Reality Tests of Superclusters in the Young Disk Population", Astronomical Journal, 110: 2862, Bibcode:1995AJ....110.2862E, doi:10.1086/117734
  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
  15. ↑ Eaton, Joel A.; et al. (September 1993), "Spots on RS CVn From Spectroscopy and Photometry", Astronomical Journal, 106: 1181, Bibcode:1993AJ....106.1181E, doi: 10.1086/116717
  16. ↑ Boboltz, D. A.; et al. (July 2003), "Astrometric Positions and Proper Motions of 19 Radio Stars", The Astronomical Journal, 126 (1): 484–493, arXiv: astro-ph/0303503 , Bibcode:2003AJ....126..484B, doi:10.1086/375462, S2CID   119455647

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