Eta Sculptoris, Latinized from η Sculptoris, is a single,[8] variable star in the central part[9] of the southern constellation of Sculptor. It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude that fluctuates around 4.81.[5] The star is located approximately 460 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +12 km/s.[6]

Eta Sculptoris

Location of η Sculptoris (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Sculptor
Right ascension	00h 27m 55.69820s[1]
Declination	−33° 00′ 25.7900″[1]
Apparent magnitude (V)	4.8 - 4.9[2]
Characteristics
Evolutionary stage	asymptotic giant branch[3]
Spectral type	M4III[4]
U−B color index	+1.81[5]
B−V color index	+1.64[5]
Variable type	semiregular variable[2]
Astrometry
Radial velocity (Rv)	+12.1±1.7[6] km/s
Proper motion (μ)	RA: −20.349[1] mas/yr Dec.: −49.911[1] mas/yr
Parallax (π)	7.0975 ± 0.2769 mas[1]
Distance	460 ± 20 ly (141 ± 5 pc)
Absolute magnitude (MV)	−0.83[7]
Details
Radius	79.96+3.70 −9.85[1] R☉
Luminosity	1,012.3±44.6[1] L☉
Temperature	3,641+247 −82[1] K
Other designations
η Scl, CD−33°152, FK5 2026, GC 544, HD 2429, HIP 2210, HR 105, SAO 192545, GSC 06994-01104
Database references
SIMBAD	data

This object is an aging red giant star,[4] currently on the asymptotic giant branch,[3] with a stellar classification of M4III.[4] With the supply of hydrogen at its core exhausted, the star has cooled and expanded. It now has 80 times the radius of the Sun.[1] Eta Sculptoris is classified as a semiregular variable with a visual magnitude that fluctuates between +4.80 and +4.90,[2] The pulsations have periods of 22.7, 23.5, 24.6, 47.3, 128.7 and 158.7 days.[10] On average, this star is radiating over a thousand times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,641 K.[1]

References