R Sculptoris is a variable star system in the southern constellation of Sculptor.[9][10] Parallax measurements provide a distance estimate of approximately 1,435 ± 98 light-years from the Sun.[1] An independent estimate based on measurements of an ejected shell surrounding the star yield a distance of 1,180 ± 140 light-years.[11] The star is drifting closer with a radial velocity of −5.4 km/s.[5]
![A visual band light curve for R Sculptoris, plotted from ASAS data[12]](http://upload.wikimedia.org/wikipedia/commons/thumb/a/ae/RSclLightCurve.png/220px-RSclLightCurve.png)
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sculptor |
| Right ascension | 01h 26m 58.09462s[1] |
| Declination | −32° 32′ 35.4377″[1] |
| Apparent magnitude (V) | +5.72[2] |
| Characteristics | |
| Spectral type | C6,5ea(Np)[3] |
| U−B color index | +7.67[2] |
| B−V color index | +3.87[2] |
| Variable type | SRb[4] |
| Astrometry | |
| Radial velocity (Rv) | −5.40[5] km/s |
| Proper motion (μ) | RA: −9.784[1] mas/yr Dec.: −30.900[1] mas/yr |
| Parallax (π) | 2.2724 ± 0.1471 mas[1] |
| Distance | 1,440 ± 90 ly (440 ± 30 pc) |
| Absolute magnitude (MV) | −0.45[6] |
| Details[7] | |
| Mass | 1.3±0.7 M☉ |
| Radius | 138.61+1.24 −0.16[1] R☉ |
| Luminosity | 2,068±171[1] L☉ |
| Surface gravity (log g) | −0.6±0.4 cgs |
| Temperature | 3,306+2 −15[1] K |
| Metallicity [Fe/H] | 0.0[3] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an aging giant star on the asymptotic giant branch with a stellar classification of C6,5ea(Np),[3] which indicates a carbon-rich atmosphere. It is a semi-regular pulsating star of the SRb[4] 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.[11]
Observations have revealed a spiral structure in the material around the star.[13] The spiral is suspected to be caused by an unseen companion star.[9] The spiral windings are consistent with an orbital period of ~350 years.[13]
Constellation of Sculptor | |||||||||||
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