Tau7 Eridani is a solitary star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 5.235.[2] Using the parallax method, the distance to this star can be estimated as around 251 light years.[1]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 47m 39.65058s[1] |
| Declination | −23° 52′ 28.8352″[1] |
| Apparent magnitude (V) | 5.235[2] |
| Characteristics | |
| Spectral type | A3 Vs[3] |
| U−B color index | +0.168[2] |
| B−V color index | +0.067[2] |
| Astrometry | |
| Radial velocity (Rv) | 28.4±0.5[4] km/s |
| Proper motion (μ) | RA: +47.46[1] mas/yr Dec.: +49.10[1] mas/yr |
| Parallax (π) | 13.00 ± 0.28 mas[1] |
| Distance | 251 ± 5 ly (77 ± 2 pc) |
| Absolute magnitude (MV) | +0.81[5] |
| Details | |
| τ7 Eri A | |
| Mass | 2.03[6] M☉ |
| Luminosity | 37.6[7] L☉ |
| Surface gravity (log g) | 3.86±0.2[8] cgs |
| Temperature | 8,740±200[8] K |
| Rotational velocity (v sin i) | 18[8] km/s |
| Age | 387[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an A-type main sequence star with a stellar classification of A3 Vs,[3] where the 's' indicates it has narrow absorption lines. It may be a chemically peculiar Am star, which means it displays unusual abundances of certain elements in its surface layers. Tau7 Eridani appears to be a low amplitude variable that displays slight fluctuations in luminosity over a period of 7.17 days. It is slowly rotating with a projected rotational velocity of 18 km/s,[8] and is around 387 million years old.[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 Gutierrez-Moreno, Adelina; et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile, 1, Publicaciones Universidad de Chile, Department de Astronomy: 1–17, Bibcode:1966PDAUC...1....1G.
- ^ a b Abt, Helmut A.; Morrell, Nidia I. (July 1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
- ^ De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347.
- ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b c David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ 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, S2CID 118665352.
- ^ a b c d Khalack, V.; LeBlanc, F. (July 2015), "Project VeSElkA: Analysis of Balmer Line Profiles of Slowly Rotating Chemically Peculiar Stars", The Astronomical Journal, 150 (1): 10, arXiv:1505.08158, Bibcode:2015AJ....150....2K, doi:10.1088/0004-6256/150/1/2, S2CID 118283214, 2.
- ^ "tau07 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.
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