Astronomy:Tau8 Eridani
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Short description: Variable star in the constellation Eridanus
| Observation data Epoch J2000.0 Equinox (celestial coordinates) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 03h 53m 42.70302s[2] |
| Declination | −24° 36′ 44.0309″[2] |
| Apparent magnitude (V) | 4.63 - 4.65[3] |
| Characteristics | |
| Spectral type | B6 V[4] |
| U−B color index | −0.48[5] |
| B−V color index | −0.13[5] |
| Variable type | SPB[3] |
| Astrometry | |
| Radial velocity (Rv) | +23[6] km/s |
| Proper motion (μ) | RA: +31.28[2] mas/yr Dec.: −7.49[2] mas/yr |
| Parallax (π) | 8.65 ± 0.30[2] mas |
| Distance | 380 ± 10 ly (116 ± 4 pc) |
| Absolute magnitude (MV) | −0.67[7] |
| Orbit[8] | |
| Period (P) | 459±4 d |
| Eccentricity (e) | 0.18±0.02 |
| Periastron epoch (T) | 2450954±7 JD |
| Argument of periastron (ω) (secondary) | 106±5° |
| Semi-amplitude (K1) (primary) | 21.7±0.4 km/s |
| Details | |
| τ8 Eri A | |
| Mass | 5.0±0.1[9] M☉ |
| Luminosity | 256[10] L☉ |
| Surface gravity (log g) | 4.00[11] cgs |
| Temperature | 11,858[10] K |
| Rotational velocity (v sin i) | 30[4] km/s |
| Age | 32.8±9.9[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Tau8 Eridani, Latinized from τ8 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.65.[5] The distance to this system can be estimated via the parallax method, yielding a value of around 380 light years.[2]
This is a single-lined[13] spectroscopic binary star system with an orbital period of about 459 days and an eccentricity of 0.18.[8] The primary component is a B-type main sequence star with a stellar classification of B6 V.[4] It is a slowly pulsating B-type star that undergoes radial-velocity variation with a frequency of 1.1569 times per day.[13] The star has about five[9] times the mass of the Sun and shines with 256 times the Sun's luminosity.[10] The outer atmosphere has an effective temperature of 11,858[10] K and may possess a longitudinal magnetic field with a strength of −140±71 G.[14]
References
- ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html, retrieved 24 September 2022.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 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.
- ↑ 3.0 3.1 "Tau 8 Eri", The International Variable Star Index (AAVSO – American Association of Variable Star Observers), https://www.aavso.org/vsx/index.php?view=detail.top&oid=14222, retrieved 16 February 2018.
- ↑ 4.0 4.1 4.2 Abt, Helmut A. et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A.
- ↑ 5.0 5.1 5.2 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.
- ↑ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 (University of Toronto: International Astronomical Union) 30: p. 57, Bibcode: 1967IAUS...30...57E.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 8.0 8.1 De Cat, P.; Aerts, C.; De Ridder, J.; Kolenberg, K.; Meeus, G.; Decin, L. (2000), "A study of bright southern slowly pulsating B stars. I. Determination of the orbital parameters and of the main frequency of the spectroscopic binaries", Astronomy and Astrophysics 355: 1015, Bibcode: 2000A&A...355.1015D.
- ↑ 9.0 9.1 9.2 Tetzlaff, N. et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 10.0 10.1 10.2 10.3 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ Lefever, K. et al. (June 2010), "Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satellite", Astronomy and Astrophysics 515: A74, doi:10.1051/0004-6361/200911956, Bibcode: 2010A&A...515A..74L.
- ↑ "tau08 Eri". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=tau08+Eri.
- ↑ 13.0 13.1 Szewczuk, W.; Daszyńska-Daszkiewicz, J. (June 2015), "Identification of pulsational modes in rotating slowly pulsating B-type stars", Monthly Notices of the Royal Astronomical Society 450 (2): 1585–1603, doi:10.1093/mnras/stv715, Bibcode: 2015MNRAS.450.1585S.
- ↑ Bagnulo, S.; Landstreet, J. D.; Fossati, L.; Kochukhov, O. (February 2012), "Magnetic field measurements and their uncertainties: the FORS1 legacy", Astronomy & Astrophysics 538: 22, doi:10.1051/0004-6361/201118098, A129, Bibcode: 2012A&A...538A.129B.
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