R Canis Majoris

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R Canis Majoris
Canis Major constellation map.svg
Red circle.svg
Location of R CMa (circled)
Observation data
Epoch J2000.0        Equinox
Constellation Canis Major
Right ascension 07h 19m 28.18202s [1]
Declination −16° 23′ 42.8773″ [1]
Apparent magnitude  (V)5.70 - 6.34 [2]
Characteristics
Spectral type F0V + G8IV [3]
U−B color index +0.01 [3]
B−V color index +0.34 [3]
Variable type Algol
Astrometry
Radial velocity (Rv)-39.0 [4]  km/s
Proper motion (μ)RA: 165.37 [1]   mas/yr
Dec.: −136.18 [1]   mas/yr
Parallax (π)23.38 ± 0.54  mas [1]
Distance 44 [3]   pc
Absolute magnitude  (MV)+2.57 [5]
Details [3]
Mass 1.67 + 0.22 + 0.8  M☉
Radius 1.78 + 1.22 + 0.83  R☉
Luminosity 8.2 + 0.49 + 0.4  L☉
Surface gravity (log g)4.16 + 3.60 + 4.50  cgs
Temperature 6,964 [5]   K
Rotational velocity (v sin i)78.3±3.9 [5]  km/s
Other designations
R  Canis Majoris, BD −16° 1898, HR  2788, HD  57167, HIP  35487, SAO  152724, GC  9758
Database references
SIMBAD data

R Canis Majoris is an eclipsing interacting binary star system in the constellation Canis Major. It varies from magnitude 5.7 to 6.34. [6] The system is unusual in the low ratio between the main two components and shortness of the orbital period. [3] It is faintly visible to the naked eye of an observer with very good observing conditions.

Contents

Variability

A visual band light curve for R Canis Majoris, adapted from Shobbrook (2005) RCMaLightCurve.png
A visual band light curve for R Canis Majoris, adapted from Shobbrook (2005)

In 1887, Edwin F. Sawyer discovered that the star, then called 155 Canis Majoris (after its listing in Uranometria Argentina), is a variable star. [8] It appears with its variable star designation. R Canis Majoris, in Annie Jump Cannon's Second catalogue of variable stars, published in 1907. [9] Eclipse timings for R Canis Majoris have been being measured since 1887, and whilst at present the time period appears constant at 1.1359 days, periodic quasi-sinusoidal variations of the eclipse arrival times have been taking place with a periodicity of around 93 years. This has led to the suggestion that there exists a third non-eclipsing body in the system whose gravitational pull is responsible for these variations. [10]

Interacting binary star

R Canis Majoris is thought to be an interacting binary star. The secondary star has exceeded its Roche lobe and accreted mass to the primary star. This has resulted in the early evolution of the secondary star into the subgiant branch, and increased helium rich material in the primary, causing it to burn brighter and have a higher effective temperature than would usually be expected for a star of its mass. [11]

Reanalysis of the system using high-resolution spectroscopy yields its two main components to have masses 1.67 ± 0.08, and 0.22 ± 0.07 times that of the Sun respectively and radii 1.78 ± 0.03 and 1.22 ± 0.07 times that of the Sun respectively. Their surface temperatures are 7300 and 4350 K. The third star has a mass 80% that of the Sun and a radius around 83% that of the Sun. A third star in the system is very faint, presumably an orange dwarf. [3]

Related Research Articles

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

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Omicron<sup>1</sup> Canis Majoris Variable star in the constellation Canis Major

Omicron1 Canis Majoris is a red supergiant star in the constellation Canis Major. It is also a variable star.

<span class="mw-page-title-main">Sigma Canis Majoris</span> Variable star in the constellation Canis Major

Sigma Canis Majoris, also named Unurgunite, is a variable star in the southern constellation of Canis Major. It is approximately 1,290 light-years from the Sun and has an average apparent visual magnitude of +3.41.

<span class="mw-page-title-main">Tau Canis Majoris</span> Variable star in the constellation Canis Major

Tau Canis Majoris is a multiple star system in the constellation Canis Major. It is approximately 5,000 light years distant from Earth and is the brightest member of the open cluster NGC 2362.

<span class="mw-page-title-main">UW Canis Majoris</span> Beta Lyrae variable star in the constellation Canis Major

UW Canis Majoris is a star in the constellation Canis Major. It is classified as a Beta Lyrae eclipsing contact binary and given the variable star designation UW Canis Majoris. Its brightness varies from magnitude +4.84 to +5.33 with a period of 4.39 days. Bode had initially labelled it as Tau2 Canis Majoris, but this designation had been dropped by Gould and subsequent authors. It is visible to the naked eye of a person under good observing conditions.

<span class="mw-page-title-main">1 Vulpeculae</span> Star in the constellation Vulpecula

1 Vulpeculae is a class B4IV star in the constellation Vulpecula. Its apparent magnitude is 4.77 and it is approximately 780 light years away based on parallax.

<span class="mw-page-title-main">EZ Canis Majoris</span> Binary star system in the constellation Canis Major

EZ Canis Majoris is binary system in the constellation of Canis Major. The primary is a Wolf-Rayet star and it is one of the ten brightest Wolf-Rayet stars, brighter than apparent magnitude 7.

<span class="mw-page-title-main">U Aquilae</span> Variable binary star system in the constellation Aquila

U Aquilae is a binary star system in the constellation Aquila, Located approximately 614 parsecs (2,000 ly) away from Earth.

<span class="mw-page-title-main">R Arae</span> Variable star in the constellation Ara

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LY Aurigae is a multiple star system in the constellation Auriga. It is an eclipsing binary variable star, dropping in brightness by 0.7 magnitudes every 4 days. The system is around a thousand light years away in the Auriga OB1 stellar association.

<span class="mw-page-title-main">42 Persei</span> Binary star system in the constellation Perseus

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<span class="mw-page-title-main">V3903 Sagittarii</span> Binary star system in the constellation Sagittarius

V3903 Sagittarii is an eclipsing binary star system in the constellation Sagittiarus. It creates an H II region LBN 29 1,070 parsecs away from the Sun.

<span class="mw-page-title-main">ZZ Boötis</span>

ZZ Boötis is a star system in the constellation Boötes. It varies from magnitude 6.79 to 7.44 over five days. Based on its parallax, measured by the Gaia spacecraft, it is about 350 light-years away.

<span class="mw-page-title-main">RR Centauri</span> Star in the constellation Centaurus

RR Centauri is a variable star of apparent magnitude maximum +7.29. It is located in the constellation of Centaurus, approximately 320 light years distant from the solar system.

Psi<sup>2</sup> Orionis Spectroscopic binary system in the constellation of Orion

Psi2 Orionis a binary star system in the equatorial constellation of Orion. It has an apparent visual magnitude of 4.6, indicating that it is visible to the naked eye. Based upon an annual parallax shift of 2.87 mass, it is roughly 1,100 light years distant from the Sun.

<span class="mw-page-title-main">CX Canis Majoris</span> Blue variable star in the constellation Canis Major

CX CMa is a blue variable star in the Canis Major constellation. Discovery of this variable is usually credited to German Astronomer Cuno Hoffmeister in 1931, although this remains uncertain.

<span class="mw-page-title-main">65 Ursae Majoris</span> Star system in the constellation Ursa Major

65 Ursae Majoris, abbreviated as 65 UMa, is a star system in the constellation of Ursa Major. With a combined apparent magnitude of about 6.5, it is at the limit of human eyesight and is just barely visible to the naked eye in ideal conditions. It is about 760 light years away from Earth.

References

  1. 1 2 3 4 5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. ↑ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  3. 1 2 3 4 5 6 7 Budding, E.; Butland, R. (2011). "Observations and analysis of the system R Canis Majoris". Monthly Notices of the Royal Astronomical Society . 418 (3): 1764–73. Bibcode:2011MNRAS.418.1764B. doi: 10.1111/j.1365-2966.2011.19597.x .
  4. ↑ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  5. 1 2 3 Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv: 1204.2459 , Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID   53666672.
  6. ↑ Watson, Christopher (4 January 2010). "R Canis Majoris". AAVSO Website. American Association of Variable Star Observers . Retrieved 18 February 2014.
  7. ↑ Shobbrook, R. R. (December 2005). "Photometry of 20 eclipsing and ellipsoidal binary systems". The Journal of Astronomical Data. 11: 7. Bibcode:2005JAD....11....7S . Retrieved 15 November 2021.
  8. ↑ Sawyer, Edwin F. (July 1887). "On a new variable of the Algol-type". Astronomical Journal. 7: 119–120. Bibcode:1887AJ......7..119S. doi:10.1086/100933 . Retrieved 1 January 2025.
  9. ↑ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C . Retrieved 1 January 2025.
  10. ↑ “Astrometric and light-travel time orbits to detect low-mass companions: a case study of the eclipsing system R Canis Majoris” "Ribas I, Arenou F, & Guinan EF - The Astronomical Journal, 123:2033-2041, 2002 April
  11. ↑ ""Near-infrared photometric studies of R Canis Majoris" Varricatt WP & Ashok NM - The Astronomical Journal, 17:2980-2997, 1999 June" . Retrieved 2009-03-08.
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