Sigma Sculptoris

Sigma Sculptoris, Latinized from σ Sculptoris, is a binary star in the southern constellation of Sculptor. It is faintly visible to the naked eye with an apparent visual magnitude of +5.54.^[3] Based upon an annual parallax shift of 14.04 mas as seen from Earth,^[2] it is located about 232 light years from the Sun.

Sigma Sculptoris

An ultraviolet light curve for Sigma Sculptoris, adapted from Manfroid and Renson (1994)[1]
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Sculptor
Right ascension	01h 02m 26.43280s[2]
Declination	−31° 33′ 07.2237″[2]
Apparent magnitude (V)	+5.54[3]
Characteristics
Spectral type	A1/2 IV[4]
U−B color index	+0.13[3]
B−V color index	+0.06[3]
Astrometry
Radial velocity (Rv)	−15.40±0.50[5] km/s
Proper motion (μ)	RA: +80.50[2] mas/yr Dec.: +14.64[2] mas/yr
Parallax (π)	14.04±0.32 mas[2]
Distance	232 ± 5 ly (71 ± 2 pc)
Absolute magnitude (MV)	+1.24[6]
Orbit[7]
Period (P)	46.9 days
Semi-major axis (a)	0.35 au
Eccentricity (e)	0.195
Inclination (i)	27° or 135°
Semi-amplitude (K1) (primary)	10.3 km/s
Details[7]
A
Mass	1.95 M☉
Radius	2.0 R☉
Luminosity	25.7[8] L☉
Surface gravity (log g)	4.02±0.14[9] cgs
Temperature	8,470 K
Rotational velocity (v sin i)	82.1±1.2[10] km/s
Age	560 Myr
B
Mass	0.72 M☉
Radius	0.67 R☉
Temperature	4,530 K
Other designations
σ Scl, CD−32°410, HD 6178, HIP 4852, HR 293, SAO 192884[11]
Database references
SIMBAD	data

The main component is a A-type star with a stellar classification of A1/A2 IV,^[4] although many modern papers use a spectral class of A2V and describe Sigma Sculptoris as a somewhat evolved main sequence star.^[7] It was suspected to be an Ap^[12] or Am star,^[13] and an Alpha2 Canum Venaticorum variable,^[14] but no chemical peculiarity or variability was found in 2018.^[13] The star has an estimated 1.95 the mass of the Sun and around two times the Sun's radius.^[7] It is spinning with a projected rotational velocity of 82 km/s^[10] and is about 560 million years old.^[7] Sigma Sculptoris radiates 25.7^[8] times the solar luminosity from its photosphere at an effective temperature of 8,470 K.^[7]

The secondary is a relatively small star with 72% the mass of the Sun, 5.7 magnitudes fainter than the primary.^[7]