R Capricorni
Variable star in the constellation Capricornus
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R Capricorni (R Cap) is a star in the constellation of Capricornus.[5] It has an apparent visual magnitude which varies between 9.4 and 14.9.[3] A mira variable and ageing red giant, it is in the asymptotic giant branch stage of its lifespan.[4] It is a carbon star.[4]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 20h 11m 18.35s[2] |
| Declination | −14° 16′ 03.4″[2] |
| Apparent magnitude (V) | 9.4 to 14.9[3] |
| Characteristics | |
| Evolutionary stage | AGB[4] |
| Spectral type | Cev[5] |
| Variable type | Mira[3] |
| Astrometry | |
| Proper motion (μ) | RA: +1.571[2] mas/yr Dec.: +1.420[2] mas/yr |
| Parallax (π) | 0.5515±0.0362 mas[2] |
| Distance | 5,900 ± 400 ly (1,800 ± 100 pc) |
| Other designations | |
| R Cap, BD−14 5663, GC 28001, SAO 163323, 2MASS J20111833−1416033[5] | |
| Database references | |
| SIMBAD | data |
John Russell Hind discovered this variable star in 1848. It appeared with its variable star designation, R Capricorni, in Annie Jump Cannon's 1907 work, Second Catalogue of Variable Stars.[6]
R Capricorni is too far from earth for its parallax to be measured effectively; Guandalini and Cristallo calculated the luminosity of Mira variables based on their periods. Using a period of 345.13 days, they calculated the absolute magnitude of R Capricorni to be −4.58.[4]
R Capricorni is losing mass at rate of 2.8×10−6 solar mass/year.[7]