χ Eridani (Latinised as Chi Eridani) is a binary star[10] 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]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 01h 55m 57.45606s[1] |
| Declination | −51° 36′ 31.9736″[1] |
| Apparent magnitude (V) | 3.70[2] / 10.7[3] |
| Characteristics | |
| Spectral type | G8IV[4] or G8IIIb CNIV[5] |
| U−B color index | +0.46[2] |
| B−V color index | +0.85[2] |
| Astrometry | |
| Radial velocity (Rv) | –6.30[6] km/s |
| Proper motion (μ) | RA: +682.281[1] mas/yr Dec.: −295.332[1] mas/yr |
| Parallax (π) | 57.3774 ± 0.3291 mas[1] |
| Distance | 56.8 ± 0.3 ly (17.43 ± 0.10 pc) |
| Absolute magnitude (MV) | 2.39 / 9.4[3] |
| Details[7] | |
| A | |
| Mass | 1.58[8] M☉ |
| Radius | 3.993±0.027 R☉ |
| Luminosity | 9.84±0.39 L☉ |
| Surface gravity (log g) | 3.42±0.10 cgs |
| Temperature | 5,115±49 K |
| Metallicity [Fe/H] | −0.18±0.07 dex |
| Rotational velocity (v sin i) | 4.50 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
| ARICNS | A |
| B | |
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.[8] The star shines with 10 times the solar luminosity from its outer atmosphere at an effective temperature of 5,115 K.[7] 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.[8]
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.[8]
References
edit- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ a b c 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.
- ^ a b 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, S2CID 16080025.
- ^ Houk, N. (1978). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 2. Dept. of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
- ^ Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
- ^ a b Rains, Adam D.; et al. (April 2020). "Precision angular diameters for 16 southern stars with VLTI/PIONIER". Monthly Notices of the Royal Astronomical Society. 493 (2): 2377–2394. arXiv:2004.02343. Bibcode:2020MNRAS.493.2377R. doi:10.1093/mnras/staa282.
- ^ a b c d 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.
- ^ "* chi Eri -- Pre-main sequence Star". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-27.
{{cite web}}: CS1 maint: postscript (link) - ^ 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, S2CID 14878976.