Chi Eridani
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 01h 55m 57.47212s[1] |
| Declination | −51° 36′ 32.0325″[1] |
| Apparent magnitude (V) | 3.70[2] / 10.7[3] |
| Characteristics | |
| Spectral type | G8IV[4] |
| U−B color index | +0.46[2] |
| B−V color index | +0.85[2] |
| Astrometry | |
| Proper motion (μ) | RA: +680.92[1] mas/yr Dec.: −283.46[1] mas/yr |
| Parallax (π) | 56.02 ± 0.38[1] mas |
| Distance | 58.2 ± 0.4 ly (17.9 ± 0.1 pc) |
| Absolute magnitude (MV) | 2.39 / 9.4[3] |
| Details[5] | |
| χ Eri A | |
| Mass | 1.58 M☉ |
| Radius | 4.06±0.16 R☉ |
| Luminosity | 392[6] L☉ |
| Surface gravity (log g) | 3.42±0.10 cgs |
| Temperature | 5,135±80 K |
| Metallicity [Fe/H] | −0.18±0.07 dex |
| Rotational velocity (v sin i) | 2.0±1.0 km/s |
| Other designations | |
Chi Eridani is a binary star[8] system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.70.[2] The distance to this system, as determined using the parallax method, is around 58 light years.[1] The pair had an angular separation of 5.0 arcseconds as of 1994. This corresponds to a projected separation of around 128 AU.[3]
The primary component is an evolving G-type subgiant star with a stellar classification of G8 IV.[4] It is about 1.6 times the mass of the Sun and has 4 times the Sun's radius.[5] The star shines with 392[6] times the solar luminosity from its outer atmosphere at an effective temperature of 5,135 K.[5] Unusually for a star of this class, it shows a photometric variability of 0.04 in magnitude, which may be due to a previous mass transfer from the secondary companion, or else from an undiscovered third companion.[5]
The companion is about 7 magnitudes fainter than the primary and may be the source of the X -ray emission from this system. This emission has a luminosity of 504.4×1027 erg s−1.[5]
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 - 1 2 3 4 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M.
- 1 2 3 Poveda, A.; et al. (April 1994), "Statistical studies of visual double and multiple stars. II. A catalogue of nearby wide binary and multiple systems", Revista Mexicana de Astronomía y Astrofísica, 28 (1): 43–89, Bibcode:1994RMxAA..28...43P. See pp. 58–59.
- 1 2 Torres, C. A. O.; et al. (December 2006), "Search for associations containing young stars (SACY). I. Sample and searching method", Astronomy and Astrophysics, 460 (3): 695–708, arXiv:astro-ph/0609258, Bibcode:2006A&A...460..695T, doi:10.1051/0004-6361:20065602.
- 1 2 3 4 5 Fuhrmann, K.; Chini, R. (2012), "Multiplicity among F-type Stars", The Astrophysical Journal Supplement, 203 (2): 20, Bibcode:2012ApJS..203...30F, doi:10.1088/0067-0049/203/2/30, 30.
- 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.
- ↑ "chi Eri -- Pre-main sequence Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-10-27.
- ↑ 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.