RR Centauri

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RR Centauri

Light curve of RR Cen.
Observation data
Epoch J2000      Equinox J2000
Constellation Centaurus
Right ascension 14h 16m 57.22s[1]
Declination −57° 51′ 15.6″[1]
Apparent magnitude (V) 7.29[2] (7.27 - 7.68[3])
Characteristics
Spectral type F0 V[4]
U−B color index +0.05[2]
B−V color index +0.36[2]
Variable type W Uma[3]
Distance
320 ± 20 ly
(98 ± 6 pc)
Absolute magnitude (MV)+1.882[4]
Inclination
(i)		81.00 ± 0.44°
Details[7]
RR Cen1
Mass1.82 ± 0.26 M☉
Radius2.1 ± 0.01 R☉
Luminosity8.89 L☉
Temperature6,912 K
RR Cen2
Mass0.38 ± 0.06 M☉
Radius1.05 ± 0.03 R☉
Luminosity2.2 L☉
Temperature6,891 ± 13 K
Cordoba Durchmusterung CD-57 5498[1]
Database references
SIMBADdata

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.[6]

The system is a contact binary of the

W UMa type - two stars in physical contact whose two components share a gaseous envelope — with a variation in brightness of 0.41 magnitude.[7] Its spectral type is A9V or F0V.[1] The binary nature of the star was discovered in 1896 by the Scottish-South African astronomer Alexander Roberts, so the system has been well observed for over a century.[8] The primary component has a mass of 1.82 solar masses, an effective temperature of around 6900 K, and a radius somewhat larger than twice the solar radius.[7]
The secondary component is 0.39 solar masses, giving a mass ratio of the system (q) of 0.210. the secondary has a temperature of about 6890 K and a radius is almost equal to the solar radius.

The orbital period of this system is 0.6057 days (14.54 h). Calculations by astronomers from the Chinese Academy of Sciences show a possible cyclic variation in orbital period over 65.1±0.4 years whose amplitude is 0.0124±0.0007 d.[7] The origin of this periodic variation could be due to the gravitational influence of a third object yet observed. Superimposed on this variation seems to be a secular increase in the period of 1.21×10−7 d/a, suggesting that there is transfer of stellar mass from secondary to primary component. If this increase is confirmed, RR Centauri may evolve into a single rapidly rotating star.

References

  1. ^ a b c d "V* RR Cen -- Eclipsing binary of W UMa type (contact binary)". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2016-02-27.
  2. ^
    Bibcode:1979A&AS...38..355L
    .
  3. ^
    Bibcode:2009yCat....102025S
    .
  4. ^
    S2CID 15071352
    .
  5. S2CID 16274339
    .
  6. ^
    S2CID 18759600
    .
  7. ^
    doi:10.1093/pasj/57.6.983
    .
  8. doi:10.1093/mnras/63.8.527
    .
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