R Horologii
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Horologium |
| Right ascension | 02h 53m 52.77010s |
| Declination | −49° 53′ 22.7305″ |
| Apparent magnitude (V) | 4.7 – 14.3 |
| Characteristics | |
| Spectral type | M5-7e |
| B−V color index | 1.044±0.011 |
| Variable type | Mira |
| Astrometry | |
| Radial velocity (Rv) | +60.0±4.4 km/s |
| Proper motion (μ) | RA: +128.567 mas/yr Dec.: +35.766 mas/yr |
| Parallax (π) | 4.3236±0.1524 mas |
| Distance | 756.0+31.6 −30.3 ly (231.8+9.7 −9.3 pc) |
| Details | |
| Mass | 0.94 M☉ |
| Radius | 630 R☉ |
| Luminosity | 8,500 L☉ |
| Surface gravity (log g) | −0.434 cgs |
| Temperature | 2,200 K |
| Metallicity [Fe/H] | +0.545 dex |
| Other designations | |
| R Hor, AAVSO 0250-50, CD−50° 860, HD 18242, HIP 13502, HR 868 | |
| Database references | |
| SIMBAD | data |
R Horologii is a red giant star approximately 760 light-years away in the southern constellation of Horologium. It is a Mira variable with a period of 404.83 days, ranging from apparent magnitude 4.7 to 14.3—one of the largest ranges in brightness known of stars in the night sky visible to the unaided eye. The star is losing mass at the rate of 5.9×10−7 M☉·y−1.