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.
| Observation data Epoch J2000.0 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 | |
| Evolutionary stage | Red clump[3] |
| Spectral type | K0 III[4] |
| U−B color index | +0.74[2] |
| B−V color index | +1.02[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.30±0.70[5] km/s |
| Proper motion (μ) | RA: +135.92[1] mas/yr Dec.: −27.53[1] mas/yr |
| Parallax (π) | 21.65 ± 0.18 mas[1] |
| Distance | 151 ± 1 ly (46.2 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.877[3] |
| Details[6] | |
| Mass | 1.29±0.01 M☉ |
| Radius | 11.17±0.06 R☉ |
| Luminosity | 54.7±0.5 L☉ |
| Surface gravity (log g) | 2.65±0.10 cgs |
| Temperature | 4,700±30 K |
| Metallicity [Fe/H] | −0.34±0.02 dex |
| Age | 3.55±0.12 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved giant star with a stellar classification of K0 III.[4] The measured angular diameter, after correcting for limb darkening, is 2.248±0.014 mas. This star is 3.55 billion years old, sufficient to have exhausted the hydrogen at its core and reached a red clump stage. It is only around 29% more massive than the Sun, but is eleven times larger. It radiates 54.7 times the solar luminosity from its outer atmosphere at an effective temperature of 4,700 K.[6]
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 d 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.
- ^ a b Liu, Y. J.; et al. (2007), "The abundances of nearby red clump giants", Monthly Notices of the Royal Astronomical Society, 382 (2): 553–66, Bibcode:2007MNRAS.382..553L, doi:10.1111/j.1365-2966.2007.11852.x
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b Gallenne, A.; Pietrzyński, G.; Graczyk, D.; Nardetto, N.; Mérand, A.; Kervella, P.; Gieren, W.; Villanova, S.; Mennickent, R. E.; Pilecki, B. (2018-08-01), "Fundamental properties of red-clump stars from long-baseline H-band interferometry", Astronomy & Astrophysics, 616: A68, arXiv:1806.09572, doi:10.1051/0004-6361/201833341, ISSN 0004-6361
- ^ "iot Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-29.
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