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] |
Astrometry | |
Radial velocity (Rv) | -16.0 [5] km/s |
Proper motion (μ) |
RA: -52.00
[6]
mas/
yr Dec.: -22.63 [6] mas/ yr |
Parallax (π) | 10.16 ± 0.61 mas [6] |
Distance | 320 ± 20
ly (98 ± 6 pc) |
Absolute magnitude (MV) | +1.882 [4] |
Orbit [7] | |
Primary | RR Cen1 |
Companion | RR Cen2 |
Period (P) | 0.60569 days |
Semi-major axis (a) | 3.92 ± 0.19 R☉ |
Eccentricity (e) | 0 |
Inclination (i) | 81.00 ± 0.44° |
Details [7] | |
RR Cen1 | |
Mass | 1.82 ± 0.26 M☉ |
Radius | 2.1 ± 0.01 R☉ |
Luminosity | 8.89 L☉ |
Temperature | 6,912 K |
RR Cen2 | |
Mass | 0.38 ± 0.06 M☉ |
Radius | 1.05 ± 0.03 R☉ |
Luminosity | 2.2 L☉ |
Temperature | 6,891 ± 13 K |
Other designations | |
Database references | |
SIMBAD | data |
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.
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] |
Astrometry | |
Radial velocity (Rv) | -16.0 [5] km/s |
Proper motion (μ) |
RA: -52.00
[6]
mas/
yr Dec.: -22.63 [6] mas/ yr |
Parallax (π) | 10.16 ± 0.61 mas [6] |
Distance | 320 ± 20
ly (98 ± 6 pc) |
Absolute magnitude (MV) | +1.882 [4] |
Orbit [7] | |
Primary | RR Cen1 |
Companion | RR Cen2 |
Period (P) | 0.60569 days |
Semi-major axis (a) | 3.92 ± 0.19 R☉ |
Eccentricity (e) | 0 |
Inclination (i) | 81.00 ± 0.44° |
Details [7] | |
RR Cen1 | |
Mass | 1.82 ± 0.26 M☉ |
Radius | 2.1 ± 0.01 R☉ |
Luminosity | 8.89 L☉ |
Temperature | 6,912 K |
RR Cen2 | |
Mass | 0.38 ± 0.06 M☉ |
Radius | 1.05 ± 0.03 R☉ |
Luminosity | 2.2 L☉ |
Temperature | 6,891 ± 13 K |
Other designations | |
Database references | |
SIMBAD | data |
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.