66 Tauri
66 Tauri, also known as r Tauri, is a binary star in the constellation of Taurus. The combined apparent magnitude of the system is 5.098,[2] with the magnitudes of the two components being 5.8 and 5.9, respectively.[3] Parallax measurements by Hipparcos put 66 Tauri at some 400 light-years (121 parsecs) away.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 23m 51.82553s[1] |
| Declination | +09° 27′ 39.4939″[1] |
| Apparent magnitude (V) | 5.098[2] (5.8 / 5.9)[3] |
| Characteristics | |
| Spectral type | A3V + A4V[4] |
| U−B color index | +0.10[5] |
| B−V color index | +0.07[5] |
| Astrometry | |
| Radial velocity (Rv) | -8.70 ± 1[6] km/s |
| Proper motion (μ) | RA: -20.32[1] mas/yr Dec.: -5.32[1] mas/yr |
| Parallax (π) | 8.24 ± 0.31[1] mas |
| Distance | 400 ± 10 ly (121 ± 5 pc) |
| Orbit[3] | |
| Period (P) | 54.77 yr |
| Semi-major axis (a) | 0.188″ |
| Eccentricity (e) | 0.720 |
| Inclination (i) | 34.2° |
| Longitude of the node (Ω) | 239.8° |
| Periastron epoch (T) | 1937.24 |
| Argument of periastron (ω) (secondary) | 332.0° |
| Details | |
| 66 Tau A | |
| Mass | 2.89[7][note 1] M☉ |
| Rotational velocity (v sin i) | 81[8] km/s |
| 66 Tau B | |
| Mass | 2.76[7][note 1] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a visual binary where the positions of the two stars are tracked over time, and used to calculate an orbit. The two stars orbit each other every 55 years.[3] Their orbit is fairly eccentric, at 0.720, and the two stars are separated by 0.188″ on average.[3] Both stars are A-type main-sequence stars with similar masses.[7]
References
- van Leeuwen, F.; et al. (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.
- Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Retrieved 13 August 2017.
- Christy, James W.; Walker, R. L., Jr. (1969). "MK Classification of 142 Visual Binaries". Publications of the Astronomical Society of the Pacific. 81: 643. Bibcode:1969PASP...81..643C. doi:10.1086/128831.
- Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
- Cvetkovic, Z.; Ninkovic, S. (2010). "On the Component Masses of Visual Binaries". Serbian Astronomical Journal. 180 (180): 71–80. Bibcode:2010SerAJ.180...71C. doi:10.2298/SAJ1080071C.
- Royer, F.; Zorec, J.; Gómez, A. E. (2007). "Rotational velocities of A-type stars". Astronomy and Astrophysics. 463 (2): 671. arXiv:astro-ph/0610785. Bibcode:2007A&A...463..671R. doi:10.1051/0004-6361:20065224.
Notes
- Cvetkovic et al. gives two possible mass sums: 2.89 / 2.76 M☉ or 2.88 / 2.77 M☉.
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