金牛座EQ
金牛座EQ是黃道星座金牛座的一顆三合星，它包括密接的食雙星。該系統過於黯淡，無法用肉眼觀察，基線的視星等為10.5等[3]。在食的期間，系統的主極小期亮度降至11.03等，然後在次極小期降至10.97等[3]。次極小期是全食[7]。根據視差的量測，它位於距離太陽約730光年的地方[2]。
| 觀測資料 曆元 J2000.0 | |
|---|---|
| 星座 | 金牛座 |
| 星官 | |
| 赤經 | 03h 48m 13.436s[2] |
| 赤緯 | +22° 18′ 50.92″[2] |
| 視星等（V） | 10.5 (-11.03)[3] |
| 特性 | |
| 光譜分類 | G2[4] |
| 變星類型 | W UMa[3] |
| 天體測定 | |
| 徑向速度 (Rv) | 71.95+1.22 −[5] km/s |
| 自行 (μ) | 赤經：+69.758 mas/yr 赤緯：−30.628 mas/yr |
| 視差 (π) | 4.4694 ± 0.0171[2] mas |
| 距離 | 730 ± 3 ly (223.7 ± 0.9 pc) |
| 軌道[6] | |
| 繞行週期 (P) | 0.341348 d |
| 半長軸 (a) | 2.48±0.03 R☉[7] |
| 偏心率 (e) | 0.00 |
| 近心點 曆元 (T) | 2,451,183.9 HJD |
| 半振幅 (K1) (primary) | 112.41+1.43 − km/s |
| 半振幅 (K2) (secondary) | 254.38+2.42 − km/s |
| 詳細資料 | |
| Primary | |
| 質量 | 1.22+0.04 −[7] M☉ |
| 半徑 | 1.14+0.01 −[7] R☉ |
| 亮度 | 1.32+0.03 −[7] L☉ |
| 溫度 | 5,800+100 −[7] K |
| Secondary | |
| 質量 | 0.54+0.02 −[7] M☉ |
| 半徑 | 0.79+0.01 −[7] R☉ |
| 亮度 | 0.63+0.02 −[7] L☉ |
| 其他命名 | |
| 參考資料庫 | |
| SIMBAD | 資料 |
恆星HV 6189在1940年被哈羅·沙普利（ Harlow Shapley）和艾米莉·M·休斯（ Emily M. Hughes）確認為短週期變星[9]，然後再1954年，蘇聯天文學家弗拉基米爾·普拉托諾維奇·采謝維奇對其進行了更深入的研究[6]。它被確定為大熊座W型變星，並被注意到位於疏散星團昴宿星團的區域[10]。對采謝維奇數據的分析以及B.S.Whitney在1972年的後續觀測表明，它的週期是可變的。他在孔科利天文臺的觀測顯示週期為8.19 h[11]。Wystan Benbow和Robert L.Mutel在1995年建立了食變星的光變曲線，顯示了恆星表面存在活動區的證據[12]。軌道週期的變化繼續被觀察到，在2002年Theodor Pribulla和Martin Vańko提出它是由系統中的第三個天體引起的。他們將其建模為低質量的紅矮星，軌道週期為50.2年[13]。
這是一個淺接觸的聯星系統[7]，屬於大熊座W型變星的A子型[3]。它的軌道週期為8.1924小時[6]，半長軸是太陽半徑的2.48倍。軌道呈現週期性變化，其週期為22.7年，振幅為0.0058天。2010年觀測到類似凌的事件[7]。質量更大的成分是一顆有很深對流層的太陽型恆星，出現磁活動，覆蓋着顯著的星斑 [4]。
參考資料
編輯- ^ ASAS-SN Variable Stars Database. ASAS-SN Variable Stars Database. ASAS-SN. [6 January 2022]. （原始內容存檔於2023-01-11）.
- ^ 2.0 2.1 2.2 2.3 Brown, A. G. A.; et al. Gaia Early Data Release 3: Summary of the contents and survey properties. Astronomy & Astrophysics. 2021, 649: A1. Bibcode:2021A&A...649A...1G. S2CID 227254300. arXiv:2012.01533
. doi:10.1051/0004-6361/202039657 . 已忽略未知參數|collaboration=(幫助) (勘誤: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR. - ^ 3.0 3.1 3.2 3.3 3.4 Samus', N. N; et al, General catalogue of variable stars, Astronomy Reports, GCVS 5.1, 2017, 61 (1): 80, Bibcode:2017ARep...61...80S, S2CID 125853869, doi:10.1134/S1063772917010085.
- ^ 4.0 4.1 Yuan, Jinzhao; Qian, Shengbang, Variation of the period and light curves of the solar-type contact binary EQ Tauri, Monthly Notices of the Royal Astronomical Society, October 2007, 381 (2): 602–610, Bibcode:2007MNRAS.381..602Y, doi:10.1111/j.1365-2966.2007.11926.x .
- ^ Bilir, S.; et al, Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation, Monthly Notices of the Royal Astronomical Society, 2005, 357 (2): 497–517, Bibcode:2005MNRAS.357..497B, S2CID 16274339, arXiv:astro-ph/0411291 , doi:10.1111/j.1365-2966.2005.08609.x.
- ^ 6.0 6.1 6.2 Rucinski, Slavek M.; et al, Radial Velocity Studies of Close Binary Stars. V., The Astronomical Journal, October 2001, 122 (4): 1974–1980, Bibcode:2001AJ....122.1974R, arXiv:astro-ph/0106160 , doi:10.1086/323106.
- ^ 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, The Triple Binary Star EQ Tau with an Active Component, The Astronomical Journal, May 2014, 147 (5): 8, Bibcode:2014AJ....147...98L, S2CID 123566937, doi:10.1088/0004-6256/147/5/98 , 98.
- ^ EQ Tau. SIMBAD. 斯特拉斯堡天文資料中心.
- ^ Shapley, Harlow; Hughes, Emily M., Variable stars in high galactic latitudes, Annals of the Astronomical Observatory of Harvard College, 1940, 90 (4): 163–175, Bibcode:1940AnHar..90..163S.
- ^ Artiukhina, N. M., Proper Motions of three W UMa Type Stars in the Pleiades Region, Peremennye Zvezdy, 1961, 13: 366, Bibcode:1961PZ.....13..366A （俄語）.
- ^ Whitney, B. S., The Period of EQ Tauri, Information Bulletin on Variable Stars, February 1972, 633 (1): 1, Bibcode:1972IBVS..633....1W.
- ^ Benbow, W. R.; Mutel, R. L., Eclipse Observations of EQ Tau, Information Bulletin on Variable Stars, May 1995, 4187 (1): 1, Bibcode:1995IBVS.4187....1B.
- ^ Pribulla, T.; Vanko, M., Photoelectric photometry of eclipsing contact binaries: U Peg, YY CrB, OU Ser and EQ Tau, Contributions of the Astronomical Observatory Skalnate Pleso, April 2002, 32 (1): 79–98, Bibcode:2002CoSka..32...79P.
進階讀物
編輯- Tvardovskyi, D. E., Third components with elliptical orbits in the eclipsing binaries: EQ Tau, IR Cas, IV Cas, RY Aqr & RZ Com, Annales Astronomiae Novae, January 2020, 1: 231–238, Bibcode:2020AANv....1..231T, arXiv:1912.12639 .
- Hasanzadeh, A.; et al, New light curve analysis and period changes of the overcontact binary EQ Tauri, New Astronomy, January 2015, 34: 262–265, Bibcode:2015NewA...34..262H, doi:10.1016/j.newast.2014.07.013.
- Elkhateeb, M. M.; Nouh, M. I., A holistic study of the eclipsing binary EQ Tau (PDF), Journal of Physics and Astronomy Research, 2014, 1 (3): 15 [2022-03-13], arXiv:1406.1661 .[失效連結]
- Alton, K. B., 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, December 2009, 37 (2): 148, Bibcode:2009JAVSO..37..148A.
- Hrivnak, Bruce J.; Lu, Wenxian; Eaton, Jeffery; Kenning, Daniel, Light-Curve Study and Physical Properties of the Contact Binary EQ Tauri, The Astronomical Journal, August 2006, 132 (2): 960–966, Bibcode:2006AJ....132..960H, S2CID 120523899, doi:10.1086/505691 .
- Alton, Kevin B., A Backyard CCD Photometric Study of the Neglected W UMa Binary EQ Tauri, Open European Journal on Variable Stars, June 2006, 39: 1, Bibcode:2006OEJV...39....1A.
- Vaňko, M.; et al, New Parameters of the Contact Binary Systems YY CRB and EQ Tau, Baltic Astronomy, 2004, 13: 151–155, Bibcode:2004BaltA..13..151V.
- Yang, Yulan; Liu, Qingyao, A Photometric Study of the Contact Binary EQ Tauri, The Astronomical Journal, December 2002, 124 (6): 3358–3363, Bibcode:2002AJ....124.3358Y, S2CID 123447240, doi:10.1086/344763 .
- Qian, Shengbang; Ma, Yuan, 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, June 2001, 113 (784): 754–763, Bibcode:2001PASP..113..754Q, S2CID 121169370, doi:10.1086/320808 .
- Buckner, M.; et al, Eclipse Timing Observations of Three Close Binaries, Information Bulletin on Variable Stars, February 1998, 4559 (1): 1, Bibcode:1998IBVS.4559....1B.