Astronomy:EQ Tauri
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Taurus |
| Right ascension | 03h 48m 13.436s[2] |
| Declination | +22° 18′ 50.92″[2] |
| Apparent magnitude (V) | 10.5 (-11.03)[3] |
| Characteristics | |
| Spectral type | G2[4] |
| Variable type | W UMa[3] |
| Astrometry | |
| Radial velocity (Rv) | 71.95±1.22[5] km/s |
| Proper motion (μ) | RA: +69.758[2] mas/yr Dec.: −30.628[2] mas/yr |
| Parallax (π) | 4.4694 ± 0.0171[2] mas |
| Distance | 730 ± 3 ly (223.7 ± 0.9 pc) |
| Orbit[6] | |
| Period (P) | 0.341348 d |
| Semi-major axis (a) | 2.48±0.03 R☉[7] |
| Eccentricity (e) | 0.00 |
| Periastron epoch (T) | 2,451,183.9 HJD |
| Semi-amplitude (K1) (primary) | 112.41±1.43 km/s |
| Semi-amplitude (K2) (secondary) | 254.38±2.42 km/s |
| Details | |
| Primary | |
| Mass | 1.22±0.04[7] M☉ |
| Radius | 1.14±0.01[7] R☉ |
| Luminosity | 1.32±0.03[7] L☉ |
| Temperature | 5,800±100[7] K |
| Secondary | |
| Mass | 0.54±0.02[7] M☉ |
| Radius | 0.79±0.01[7] R☉ |
| Luminosity | 0.63±0.02[7] L☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
EQ Tauri is a triple star system in the equatorial constellation of Taurus that includes a contact eclipsing binary. The system is too faint to be viewed with the naked eye, having a baseline apparent visual magnitude of 10.5.[3] During the primary eclipse, the brightness of the system drops to magnitude 11.03, then to 10.97 during the secondary minimum.[3] The secondary eclipse is total.[7] Based on parallax measurements, it is located at a distance of approximately 730 light years from the Sun.[2]
The star HV 6189 was identified as a short-period variable by H. Shapley and E. M. Hughes in 1940,[9] then was more closely studied by Soviet astronomer V. P. Tsesevich in 1954.[6] It was determined to be a W UMa-type variable and was noted for being located in the region of the Pleiades open cluster.[10] An analysis of data from Tsesevich and subsequent observations by B. S. Whitney in 1972 suggested that the period is variable. His observations from Konkoly Observatory showed a period of 8.19 h.[11] W. R. Benbow and R. L. Mutel built a light curve of the eclipsing variable in 1995 that displayed evidence of an active region on the stellar surface.[12] Orbital period changes continued to be observed, and in 2002 T. Pribulla and M. Vanko suggested it is caused by a third body in the system. They modeled it as a low mass red dwarf with an orbital period of 50.2 years.[13]
This is a shallow contact binary system,[7] belonging to sub-type A of the W Ursae Majoris class.[3] It has an orbital period of 8.1924 hours[6] and a semimajor axis of 2.48 times the radius of the Sun. The orbit shows a cyclical change with a period of 22.7 years and an amplitude of 0.0058 days. A transit-like event was observed in 2010.[7] The more massive component is a solar-type star with a deep convection zone that appears magnetically active with a significant coverage of star spots.[4]
References
- ↑ "ASAS-SN Variable Stars Database". ASAS-SN. https://asas-sn.osu.edu/variables/lookup.
- ↑ 2.0 2.1 2.2 2.3 2.4 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 Samus', N. N et al. (2017), "General catalogue of variable stars", Astronomy Reports, GCVS 5.1 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 4.0 4.1 Yuan, Jinzhao; Qian, Shengbang (October 2007), "Variation of the period and light curves of the solar-type contact binary EQ Tauri", Monthly Notices of the Royal Astronomical Society 381 (2): 602–610, doi:10.1111/j.1365-2966.2007.11926.x, Bibcode: 2007MNRAS.381..602Y.
- ↑ Bilir, S. et al. (2005), "Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation", Monthly Notices of the Royal Astronomical Society 357 (2): 497–517, doi:10.1111/j.1365-2966.2005.08609.x, Bibcode: 2005MNRAS.357..497B.
- ↑ 6.0 6.1 6.2 Rucinski, Slavek M. et al. (October 2001), "Radial Velocity Studies of Close Binary Stars. V.", The Astronomical Journal 122 (4): 1974–1980, doi:10.1086/323106, Bibcode: 2001AJ....122.1974R.
- ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 Li, K. et al. (May 2014), "The Triple Binary Star EQ Tau with an Active Component", The Astronomical Journal 147 (5): 8, doi:10.1088/0004-6256/147/5/98, 98, Bibcode: 2014AJ....147...98L.
- ↑ "EQ Tau". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=EQ+Tau.
- ↑ Shapley, Harlow; Hughes, Emily M. (1940), "Variable stars in high galactic latitudes", Annals of the Astronomical Observatory of Harvard College 90 (4): 163–175, Bibcode: 1940AnHar..90..163S.
- ↑ Artiukhina, N. M. (1961), "Proper Motions of three W UMa Type Stars in the Pleiades Region" (in ru), Peremennye Zvezdy 13: 366, Bibcode: 1961PZ.....13..366A.
- ↑ Whitney, B. S. (February 1972), "The Period of EQ Tauri", Information Bulletin on Variable Stars 633 (1): 1, Bibcode: 1972IBVS..633....1W.
- ↑ Benbow, W. R.; Mutel, R. L. (May 1995), "Eclipse Observations of EQ Tau", Information Bulletin on Variable Stars 4187 (1): 1, Bibcode: 1995IBVS.4187....1B.
- ↑ Pribulla, T.; Vanko, M. (April 2002), "Photoelectric photometry of eclipsing contact binaries: U Peg, YY CrB, OU Ser and EQ Tau", Contributions of the Astronomical Observatory Skalnate Pleso 32 (1): 79–98, Bibcode: 2002CoSka..32...79P.
Further reading
- Tvardovskyi, D. E. (January 2020), "Third components with elliptical orbits in the eclipsing binaries: EQ Tau, IR Cas, IV Cas, RY Aqr & RZ Com", Annales Astronomiae Novae 1: 231–238, Bibcode: 2020AANv....1..231T.
- Hasanzadeh, A. et al. (January 2015), "New light curve analysis and period changes of the overcontact binary EQ Tauri", New Astronomy 34: 262–265, doi:10.1016/j.newast.2014.07.013, Bibcode: 2015NewA...34..262H.
- Elkhateeb, M. M.; Nouh, M. I. (2014), "A holistic study of the eclipsing binary EQ Tau", Journal of Physics and Astronomy Research 1 (3): 15, https://www.academia.edu/download/35692670/PDF_Edited.pdf, retrieved 2022-03-13.[|permanent dead link|dead link}}]
- Alton, K. B. (December 2009), "A Multi-year Multi-passband CCD Photometric Study of the W UMa Binary EQ Tauri", The Journal of the American Association of Variable Star Observers 37 (2): 148, Bibcode: 2009JAVSO..37..148A.
- Hrivnak, Bruce J.; Lu, Wenxian; Eaton, Jeffery; Kenning, Daniel (August 2006), "Light-Curve Study and Physical Properties of the Contact Binary EQ Tauri", The Astronomical Journal 132 (2): 960–966, doi:10.1086/505691, Bibcode: 2006AJ....132..960H.
- Alton, Kevin B. (June 2006), "A Backyard CCD Photometric Study of the Neglected W UMa Binary EQ Tauri", Open European Journal on Variable Stars 39: 1, Bibcode: 2006OEJV...39....1A.
- Vaňko, M. et al. (2004), "New Parameters of the Contact Binary Systems YY CRB and EQ Tau", Baltic Astronomy 13: 151–155, Bibcode: 2004BaltA..13..151V.
- Yang, Yulan; Liu, Qingyao (December 2002), "A Photometric Study of the Contact Binary EQ Tauri", The Astronomical Journal 124 (6): 3358–3363, doi:10.1086/344763, Bibcode: 2002AJ....124.3358Y.
- Qian, Shengbang; Ma, Yuan (June 2001), "Period Studies of Some Neglected Close Binaries: EP Andromedae, V724 Aquilae, SS Comae, AM Eridani, FZ Orionis, BY Pegasi, EQ Tauri, and NO Vulpeculae", The Publications of the Astronomical Society of the Pacific 113 (784): 754–763, doi:10.1086/320808, Bibcode: 2001PASP..113..754Q.
- Buckner, M. et al. (February 1998), "Eclipse Timing Observations of Three Close Binaries", Information Bulletin on Variable Stars 4559 (1): 1, Bibcode: 1998IBVS.4559....1B.
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