| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 02 40 40.03501 |
| Declination | −39° 51′ 19.3541″ |
| Apparent magnitude (V) | 4.11 |
| Characteristics | |
| Evolutionary stage | Red clump |
| Spectral type | K0 III |
| U−B color index | +0.74 |
| B−V color index | +1.02 |
| Astrometry | |
| Radial velocity (Rv) | −9.30±0.70 km/s |
| Proper motion (μ) | RA: +135.92 mas/yr Dec.: −27.53 mas/yr |
| Parallax (π) | 21.65 ± 0.18 mas |
| Distance | 151 ± 1 ly (46.2 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.877 |
| Details | |
| 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 | −0.34±0.02 dex |
| Age | 3.55±0.12 Gyr |
| Other designations | |
| ι Eri, CD−40° 689, FK5 1075, HD 16815, HIP 12486, HR 794, SAO 215999. | |
| 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. With an annual parallax shift of 0.02165 arcseconds, it lies at an estimated distance of about 151 light years.
This is an evolved giant star with a stellar classification of K0 III. 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.
References
- ^ 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.
- ^ 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.
- ^ 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
- ^ 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.
- ^ 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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