R Sculptoris
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sculptor |
| Right ascension | 01h 26m 58.09462s |
| Declination | −32° 32′ 35.4377″ |
| Apparent magnitude (V) | +5.5 - 8.0 |
| Characteristics | |
| Evolutionary stage | AGB |
| Spectral type | C6,5ea(Np) |
| U−B color index | +7.67 |
| B−V color index | +3.87 |
| Variable type | SRb |
| Astrometry | |
| Radial velocity (Rv) | −5.40 km/s |
| Proper motion (μ) | RA: −9.784 mas/yr Dec.: −30.900 mas/yr |
| Parallax (π) | 2.2724±0.1471 mas |
| Distance | 1,180±140 ly (361±44 pc) |
| Absolute magnitude (MV) | −0.45 |
| Details | |
| Mass | 1.3±0.7 M☉ |
| Radius | 411±43 R☉ |
| Luminosity | 8,000±1,000 L☉ |
| Surface gravity (log g) | −0.5±0.1 cgs |
| Temperature | 2640±80 K |
| Metallicity [Fe/H] | 0.0 dex |
| Other designations | |
| R Scl, CD−33°525, HD 8879, HIP 6759, HR 423, SAO 193122, WDS J01270-3233A, AAVSO 0122-33 | |
| Database references | |
| SIMBAD | data |
R Sculptoris is a variable star system in the southern constellation of Sculptor. Parallax measurements provide a distance estimate of approximately 1,435 ± 98 light-years from the Sun. An independent estimate based on measurements of an ejected shell surrounding the star yield a distance of 1,180 ± 140 light-years. The star is drifting closer with a radial velocity of −5.4 km/s.
Benjamin Apthorp Gould discovered that the star's brightness varies, in 1872. It was listed with its variable star designation, R Sculptoris, in Annie Jump Cannon's 1907 work Second Catalog of Variable Stars. Both AAVSO and ASAS data shows that R Sculptoris is occasionally brighter than 6th magnitude, and faintly visible to the naked eye under excellent observing conditions.
This is an aging giant star on the asymptotic giant branch with a stellar classification of C6,5ea(Np), which indicates a carbon-rich atmosphere. It is a semi-regular pulsating star of the SRb type that is nearing the end of its fusing lifespan. A sine curve fitted to the last ten pulsation cycles prior to 2017 give a pulsation period of 376 days with an amplitude of 0.75 magnitude. The star is shedding its outer atmosphere, and it is surrounded by a thin shell of dust and gas that was created during the most recent thermal pulse around 2,000 years ago.
Observations have revealed a spiral structure in the material around the star. The spiral is suspected to be caused by an unseen companion star. The spiral windings are consistent with an orbital period of ~350 years.