Upsilon2 Eridani
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 35m 33.03834s[1] |
| Declination | −30° 33′ 44.4297″[1] |
| Apparent magnitude (V) | 3.804[2] |
| Characteristics | |
| Spectral type | G8+ III[3] |
| U−B color index | +0.740[2] |
| B−V color index | +0.968[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.0±0.9[4] km/s |
| Proper motion (μ) | RA: −49.27[1] mas/yr Dec.: −12.72[1] mas/yr |
| Parallax (π) | 15.25 ± 0.19[1] mas |
| Distance | 214 ± 3 ly (65.6 ± 0.8 pc) |
| Details | |
| Radius | 16[5] R☉ |
| Luminosity | 138[6] L☉ |
| Surface gravity (log g) | 2.77±0.07[7] cgs |
| Temperature | 5,074±30[7] K |
| Metallicity [Fe/H] | 0.04±0.03[7] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
Upsilon2 Eridani (Upsilon2 Eri, υ2 Eridani, υ2 Eri) is a star in the constellation of Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.8[2] Based upon an annual parallax shift of 0.01525″,[1] it is approximately 214 light-years from the Sun.
In Chinese, 天園 (Tiān Yuán), meaning Celestial Orchard, refers to an asterism consisting of υ2 Eridani, χ Eridani, φ Eridani, κ Eridani, HD 16754, HD 23319, θ Eridani, HD 24072, HD 24160, υ4 Eridani, 43 Eridani and υ1 Eridani.[9] Consequently, υ2 Eridani itself is known as 天園十二 (Tiān Yuán shíèr, English: the Twelfth Star of Celestial Orchard.)[10]
This is a evolved red clump[11] giant star with a stellar classification of G8+ III.[3] The measured angular diameter is 2.21 mas.[12] At an estimated distance of the star, this yields a physical size of around 16 times the radius of the Sun.[5] It radiates 138[6] times the solar luminosity from its outer atmosphere at an effective temperature of 5074 K.[7]
References
- 1 2 3 4 5 6 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. - 1 2 3 4 Gutierrez-Moreno, Adelina; et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode:1966PDAUC...1....1G.
- 1 2 Keenan, P.; McNeil, R. (October 1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
- 1 2 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- 1 2 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.
- 1 2 3 4 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.
- ↑ "ups02 Eri -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-10-13.
- ↑ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ↑ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ↑ Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278.
- ↑ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
