Astronomy:Iota Eridani
From HandWiki
Short description: Solitary red clump giant star in the constellation Eridanus
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 02h 40m 40.03501s[1] |
| Declination | −39° 51′ 19.3541″[1] |
| Apparent magnitude (V) | 4.11[2] |
| Characteristics | |
| Spectral type | K0 III[3] |
| U−B color index | +0.74[2] |
| B−V color index | +1.02[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.30±0.70[4] km/s |
| Proper motion (μ) | RA: +135.92[1] mas/yr Dec.: −27.53[1] mas/yr |
| Parallax (π) | 21.65 ± 0.18[1] mas |
| Distance | 151 ± 1 ly (46.2 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.877[5] |
| Details | |
| Mass | 1.42[2] M☉ |
| Radius | 11[6] R☉ |
| Luminosity | 57.5[2] L☉ |
| Surface gravity (log g) | 2.60±0.10[7] cgs |
| Temperature | 4,683±35[2] K |
| Metallicity [Fe/H] | −0.33±0.10[7] dex |
| Age | 4.12[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Eridani (ι Eri) is a solitary star in the constellation Eridanus. It is visible to the naked eye with an apparent magnitude of 4.11.[2] With an annual parallax shift of 0.02165 arcseconds,[1] it lies at an estimated distance of about 151 light years.
This is an evolved red clump[5] giant star with a stellar classification of K0 III.[3] The measured angular diameter, after correcting for limb darkening, is 2.18±0.02 mas.[9] At an estimated distance of the star, this yields a physical size of around 11 times the radius of the Sun.[6] It has 1.42 times the mass of the Sun and radiates 57.5 times the solar luminosity from its outer atmosphere at an effective temperature of 4,683 K.[2] It is around four billion years old.[2]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 3.0 3.1 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode: 1978mcts.book.....H.
- ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 5.0 5.1 Liu, Y. J. et al. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society 382 (2): 553–66. doi:10.1111/j.1365-2966.2007.11852.x. Bibcode: 2007MNRAS.382..553L.
- ↑ 6.0 6.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(46.2\cdot 2.18\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 21.7\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 7.0 7.1 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, doi:10.1093/mnras/stv189, Bibcode: 2015MNRAS.448.2749A.
- ↑ "iot Eri". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Eri.
- ↑ Richichi, A. et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
 |  |
