Eta Circini

Eta Circini, Latinized from η Circini, is the Bayer designation for a solitary^[8] star located in the southern constellation of Circinus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.17.^[3] The distance to this star, as determined from an annual parallax shift of 11.8 mas, is around 277 light years.

η Circini

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Circinus[1]
Right ascension	15h 04m 48.18757s[2]
Declination	−64° 01′ 52.8641″[2]
Apparent magnitude (V)	5.17[3]
Characteristics
Evolutionary stage	red giant branch[2]
Spectral type	G8 III[4]
B−V color index	+0.93[3]
Astrometry
Radial velocity (Rv)	44.8±0.8[5] km/s
Proper motion (μ)	RA: +102.058[2] mas/yr Dec.: 8.499[2] mas/yr
Parallax (π)	11.7561±0.0661 mas[2]
Distance	277 ± 2 ly (85.1 ± 0.5 pc)
Absolute magnitude (MV)	+0.52[1]
Details
Mass	2.9[2] M☉
Radius	10[2] R☉
Luminosity	78[2] L☉
Surface gravity (log g)	2.70[2] cgs
Temperature	5,250[2] K
Metallicity [Fe/H]	−0.37±0.02[6] dex
Age	414[2] Myr
Other designations
η Cir, CPD−63°3493, HD 132905, HIP 73776, HR 5593, SAO 253005[7]
Database references
SIMBAD	data

This is an evolved G-type giant star with a stellar classification of G8 III.^[4] It is radiating an estimated 78 times the solar luminosity from its outer atmosphere at an effective temperature of 5,250 K.^[6]