Astronomy:39 Eridani
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 14m 23.68902s[1] |
| Declination | −10° 15′ 22.6083″[1] |
| Apparent magnitude (V) | 4.87[2] (5.07 + 8.68)[3] |
| Characteristics | |
| Spectral type | K3 III + G2 V[3] |
| B−V color index | 1.156±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | 6.8±0.8[2] km/s |
| Proper motion (μ) | RA: −7.19[1] mas/yr Dec.: −161.05[1] mas/yr |
| Parallax (π) | 13.46 ± 0.60[1] mas |
| Distance | 240 ± 10 ly (74 ± 3 pc) |
| Absolute magnitude (MV) | 0.52[2] |
| Details | |
| 39 Eri A | |
| Mass | 1.77±0.49[4] M☉ |
| Radius | 12[5] R☉ |
| Luminosity | 81.3[6] L☉ |
| Surface gravity (log g) | 2.42±0.11[4] cgs |
| Temperature | 4,641±92[4] K |
| Metallicity [Fe/H] | 0.18±0.06[2] dex |
| Rotational velocity (v sin i) | 1.6[5] km/s |
| Age | 1.12+0.36 −0.27[4] Gyr |
| 39 Eri B | |
| Radius | 1.15+0.10 −0.06[7] R☉ |
| Luminosity | 1.369+0.07 −0.06[7] L☉ |
| Temperature | 5,816+168 −223[7] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
39 Eridani is a wide binary star[3] system in the equatorial constellation of Eridanus. It is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 4.87.[2] As of 2015, the components had an angular separation of 6.4″ along a position angle of 143°.[9] The system is moving further from the Sun with a heliocentric radial velocity of +7 km/s.[2]
The magnitude 5.07[3] primary, designated component A, is an aging giant star with a stellar classification of K3 III.[3] This object is more than a billion[4] years old with 1.77[4] times the mass of the Sun. With the hydrogen at its core exhausted, the star has expanded to 12[5] times the Sun's radius. It is a candidate super metal-rich star, showing a significant overabundance of iron compared to the Sun.[10] 39 Eridani A is radiating 81.3[6] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,641 K.[4]
The secondary, component B, is a magnitude 8.68[3] G-type main-sequence star with a class of G2 V.[3] It has 1.15[7] times the Sun's radius and shines with 1.37 times the luminosity of the Sun at an effective temperature of 5,816 K.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Feuillet, Diane K. et al. (2016), "Determining Ages of APOGEE Giants with Known Distances", The Astrophysical Journal 817 (1): 40, doi:10.3847/0004-637x/817/1/40, Bibcode: 2016ApJ...817...40F.
- ↑ 5.0 5.1 5.2 Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M.
- ↑ 6.0 6.1 Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal 150 (3): 88, doi:10.1088/0004-6256/150/3/88, Bibcode: 2015AJ....150...88L.
- ↑ 7.0 7.1 7.2 7.3 7.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ "39 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=39+Eri.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, retrieved 2015-07-22
- ↑ Buzzoni, A.; Chavez, M.; Malagnini, M. L.; Morossi, C. (November 2001), "Lick Spectral Indices for Super-Metal-rich Stars", The Publications of the Astronomical Society of the Pacific 113 (789): 1365–1377, doi:10.1086/323625, Bibcode: 2001PASP..113.1365B.
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