Eta Circini, Latinized from η Circini, is the Bayer designation for a solitary[9] star located in the southern constellation of Circinus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.17.[2] The distance to this star, as determined from an annual parallax shift of 11.82 mas,[1] is around 276 light years.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Circinus |
| Right ascension | 15h 04m 48.18600s[1] |
| Declination | −64° 01′ 52.8611″[1] |
| Apparent magnitude (V) | 5.17[2] |
| Characteristics | |
| Spectral type | G8 III[3] |
| B−V color index | +0.93[2] |
| Astrometry | |
| Radial velocity (Rv) | 44.8±0.8[4] km/s |
| Proper motion (μ) | RA: +102.65[1] mas/yr Dec.: +9.35[1] mas/yr |
| Parallax (π) | 11.82 ± 0.30 mas[1] |
| Distance | 276 ± 7 ly (85 ± 2 pc) |
| Absolute magnitude (MV) | +0.52[5] |
| Details | |
| Luminosity | 64[6] L☉ |
| Surface gravity (log g) | 2.69±0.05[7] cgs |
| Temperature | 4,954±22[7] K |
| Metallicity [Fe/H] | −0.37±0.02[7] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved G-type giant star with a stellar classification of G8 III.[3] It is radiating an estimated 64[6] times the solar luminosity from its outer atmosphere at an effective temperature of 4,954 K.[7]
References
edit- ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ 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.
- ^ 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.
- ^ 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, S2CID 119257644.
- ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ a b c d 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.
{{cite web}}: CS1 maint: postscript (link) - ^ 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.