47 Capricorni
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 21h 46m 16.26887s |
| Declination | −09° 16′ 33.3799″ |
| Apparent magnitude (V) | 6.00 (5.90 - 6.14) |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | M2III |
| B−V color index | 1.629±0.010 |
| Variable type | SRb |
| Astrometry | |
| Radial velocity (Rv) | +19.80±0.89 km/s |
| Proper motion (μ) | RA: +18.731 mas/yr Dec.: +8.387 mas/yr |
| Parallax (π) | 2.7933±0.2052 mas |
| Distance | 1,170 ± 90 ly (360 ± 30 pc) |
| Absolute magnitude (MV) | −1.76 |
| Details | |
| Radius | 102+11 −10 R☉ |
| Luminosity | 1,940±162 L☉ |
| Temperature | 3,784+188 −186 K |
| Other designations | |
| c2 Cap, 47 Cap, AG Cap, BD−09°5833, HD 207005, HIP 107487, HR 8318, SAO 145648 | |
| Database references | |
| SIMBAD | data |
47 Capricorni is a variable star located around 1,170 light years from the Sun in the southern constellation Capricornus, near the northern border with Aquarius. It has the variable star designation of AG Capricorni and a Bayer designation of c2 Capricorni; 47 Capricorni is the Flamsteed designation. This object is visible to the naked eye as a dim, red-hued point of light with an apparent visual magnitude that varies between 5.90 and 6.14. The star is receding from the Earth with a heliocentric radial velocity of +20 km/s.
In 1963, Alan William James Cousins announced that 47 Capricorni is a variable star. It was given its variable star designation in 1973.
This is an aging red giant star with a stellar classification of M2III. It is a semiregular variable star of subtype SRb with a period of 30.592 days and a maximum brightness of 5.9 magnitude. With the supply of hydrogen at its core exhausted, the star has expanded to around 102 times the Sun's radius. It is radiating 1,940 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,784 K.