Eta 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: +103.058 mas/yr[2] Dec.: +8.499 mas/yr[2] |
| 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 | 2.90±0.04[2] M☉ |
| Radius | 10.68±0.22[2] R☉ |
| Luminosity | 78.0±0.8[2] L☉ |
| Surface gravity (log g) | 2.7022+0.01 −0.05[2] cgs |
| Temperature | 5,250±4[2] K |
| Metallicity [Fe/H] | −0.37±0.02[6] dex |
| Age | 414±41[2] Myr |
| Other designations | |
| η Cir, CPD−63°3493, HD 132905, HIP 73776, HR 5593, SAO 253005[7] | |
| Database references | |
| SIMBAD | data |
Eta Circini is a solitary[8] star located in the southern constellation of Circinus. Its name is a Bayer designation that is Latinized from η Circini, and abbreviated Eta Cir or η Cir. This star 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. The star is drifting further away from the Sun with a line of sight velocity component of 45 km/s.[5]
This is an evolved G-type giant star with a stellar classification of G8 III.[4] It is 414[2] million years old with 2.9 times the mass of the Sun and 10.7 times the Sun's radius.[2] The star is radiating 78[2] times the solar luminosity from its enlarged photosphere at an effective temperature of 5,250 K.[6]
References
[edit]- ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015 XHIP record for this object at VizieR.
- ^ a b c d e f g h i j k l m n Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875 Gaia DR3 record for this source at VizieR.
- ^ a b c Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa, 27: 11, Bibcode:1968MNSSA..27...11C.
- ^ a b Houk, Nancy; Cowley, A. P. (1979), University of Michigan Catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ a b Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
- ^ a b Alves, S.; et al. (April 2015), "Determination of the spectroscopic stellar parameters for 257 field giant stars", Monthly Notices of the Royal Astronomical Society, 448 (3): 2749–2765, arXiv:1503.02556, Bibcode:2015MNRAS.448.2749A, doi:10.1093/mnras/stv189.
- ^ "eta Cir", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-01-18
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
