金牛座EU
| 觀測資料 曆元 J2000.0 | |
|---|---|
| 星座 | 金牛座 |
| 星官 | |
| 赤經 | 05h 45m 40.529s[1] |
| 赤緯 | 18° 39′ 24.82″[1] |
| 視星等（V） | 8.07[2] (7.90 to 8.25)[3] |
| 特性 | |
| 光譜分類 | G5[4] |
| B−V 色指數 | 0.676+0.018 −[2] |
| 變星類型 | s-Cepheid[3] |
| 天體測定 | |
| 徑向速度 (Rv) | −2.5+0.3 −[5] km/s |
| 自行 (μ) | 赤經：1.155 mas/yr 赤緯：−2.455 mas/yr |
| 視差 (π) | 0.8262 ± 0.0233[1] mas |
| 距離 | 3,900 ± 100 ly (1,210 ± 30 pc) |
| 絕對星等 (MV) | −2.77+0.15 −[6] |
| 詳細資料 | |
| 質量 | 4.95+0.20 −[6] M☉ |
| 半徑 | 30.23+1.43 −[6] R☉ |
| 亮度 | 1,038+140 −[6] L☉ |
| 溫度 | 6,404 (6,185 to 6,626)[7] K |
| 金屬量 [Fe/H] | −0.06[8] dex |
| 年齡 | 195[8] Myr |
| 其他命名 | |
| 參考資料庫 | |
| SIMBAD | 資料 |
金牛座EU是在黃道星座金牛座的一顆變星。平均的視星等的亮度為8.07等[2]，它太微弱了，因此肉眼看不到。基於視差的測量，到這顆恆星的距離約為3,900光年[1]，但它正在以-2.5公里/秒的徑向速度漂移[5]。這顆恆星在黃道附近的位置意味着它會發生月掩星的事件[10]。
數據的金牛座EU 光變曲線[11]。
這顆恆星的變異性最早是由庫諾·霍夫邁斯特在1949年報導的，但後來他又報告說它沒有變異。由佛蘭克·布拉德肖·伍德和同事於1963年根據阿扎爾諾娃（T. A. Azarnova）在1950-1951年的觀察，它最初被歸類為大熊座W型變星。愛德華·吉南在1966年對光電數據的分析表明，這是一顆造父型變星，其短的脈動週期約為2.105天[12]。他在1972年將這一時期精確為2.1051+0.0004
−天[13]。
1981年對這個和其它造父變星的光變曲線的研究表明，它屬於一個具有異常短時間和獨特行為的小群體。這表明金牛座EU可能是「第一個泛音」脈動星[14]。1987年，Gieren和傑米·馬修斯提出這顆恆星可能有兩個脈動週期，但後來被駁斥了。 現在的證據主要支援恆星脈動處於「徑向第一泛音模式」的觀點。對於這類恆星來說，脈動週期中1%的半徑變化相對較小[6]， 到2007年，分散在35年時間範圍內的觀測表明，這顆造父變星的脈動週期可能已經改變[15]。
參考資料
[編輯]- ^ 1.0 1.1 1.2 1.3 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. - ^ 2.0 2.1 2.2 Anderson, E.; Francis, Ch., XHIP: An extended hipparcos compilation, Astronomy Letters, 2012, 38 (5): 331, Bibcode:2012AstL...38..331A, S2CID 119257644, arXiv:1108.4971 , doi:10.1134/S1063773712050015.
- ^ 3.0 3.1 Samus, N. N.; et al, General Catalogue of Variable Stars, Astronomy Reports, 5.1, 2017, 61 (1): 80–88, Bibcode:2017ARep...61...80S, S2CID 125853869, doi:10.1134/S1063772917010085.
- ^ Cannon, A. J.; Pickering, E. C., Henry Draper Catalogue and Extension (Cannon+ 1918-1924; ADC 1989), VizieR Online Data Catalog, October 1, 1993, 3135, Bibcode:1993yCat.3135....0C.
- ^ 5.0 5.1 Gontcharov, G. A., Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system, Astronomy Letters, November 2006, 32 (11): 759–771, Bibcode:2006AstL...32..759G, S2CID 119231169, arXiv:1606.08053 , doi:10.1134/S1063773706110065.
- ^ 6.0 6.1 6.2 6.3 6.4 Gieren, Wolfgang P.; et al, The Short-Period Cepheid EU Tau. II. Physical Properties of the Star, Astronomical Journal, April 1990, 99: 1196, Bibcode:1990AJ.....99.1196G, doi:10.1086/115408.
- ^ Bersier, D.; et al, Fundamental parameters of Cepheids. IV. Radii and luminosities, Astronomy and Astrophysics, April 1997, 320: 228–236, Bibcode:1997A&A...320..228B.
- ^ 8.0 8.1 Marsakov, V. A.; et al, Properties of the population of classical Cepheids in the Galaxy, Astronomy Letters, 2013, 39 (12): 851, Bibcode:2013AstL...39..851M, S2CID 119788977, doi:10.1134/S1063773713120050.
- ^ EU Tau. SIMBAD. 斯特拉斯堡天文資料中心.
- ^ Evans, D. S.; Edwards, D. A., Photoelectric observations of lunar occultations. XII, Astronomical Journal, August 1981, 86: 1277−1287, Bibcode:1981AJ.....86.1277E, doi:10.1086/113008. In particular, the SAO 94837 entry on p. 1280.
- ^ MAST: Barbara A. Mikulski Archive for Space Telescopes. Space Telescope Science Institute. [8 December 2021]. （原始內容存檔於2023-03-27）.
- ^ Guinan, E. F., EU Tauri, Information Bulletin on Variable Stars, December 1966, 170: 1, Bibcode:1966IBVS..170....1G.
- ^ Guinan, E. F., UBV beta photometry of EU Tau, Publications of the Astronomical Society of the Pacific, February 1972, 84: 56, Bibcode:1972PASP...84...56G, S2CID 120659500, doi:10.1086/129245.
- ^ Simon, N. R.; Lee, A. S., The structural properties of cepheid light curves, Astrophysical Journal, August 1981, 248: 291–297 [2023-08-22], Bibcode:1981ApJ...248..291S, doi:10.1086/159153, （原始內容存檔於2023-08-02）.
- ^ Boyer, Kirk; et al, EU Tauri: An S-cepheid With A Changing Period, Bulletin of the American Astronomical Society, December 2007, 39: 845, Bibcode:2007AAS...211.6014B.
進階讀物
[編輯]- Matthews, J. M.; Gieren, W. P., Schmidt, E. G. , 編, Secular Changes in the Light Curve of the Short-Period Cepheid EU Tau, The Use of pulsating stars in fundamental problems of astronomy, Proceedings of IAU Colloq. 111, held in Lincoln, NE, 15–17 August 1988 (Cambridge University Press), 1989: 275, Bibcode:1989upsf.conf..275M.
- Gieren, Wolfgang P.; et al, The Short-Period Cepheid EU Tau. I. New Photometric and Radial Velocity Data, Astronomical Journal, November 1989, 98: 1672, Bibcode:1989AJ.....98.1672G, doi:10.1086/115253.
- Fernie, J. D., A check on EU Tauri, Publications of the Astronomical Society of the Pacific, October 1987, 99: 1093–1096, Bibcode:1987PASP...99.1093F, S2CID 120308156, doi:10.1086/132084.
- Matthews, Jaymie M.; Gieren, Wolfgang P., Cox, A. N.; et al , 編, Frequency Analysis of the Unusual Short-Period Cepheid EU Tauri, Stellar Pulsation; Proceedings of the Conference held as a Memorial to John P. Cox at the Los Alamos National Laboratory, Los Alamos, NM, Aug. 11-15, 1986. Lecture Notes in Physics, Vol. 274, Lecture Notes in Physics 274 (Berlin: Springer-Verlag), 1987, 274: 187, Bibcode:1987LNP...274..187M, ISBN 978-3-540-17668-8, doi:10.1007/3-540-17668-3_202.
- Gieren, W. P., Madore, B. F. , 編, A Study of the Short-period Cepheid EU-Tauri (PDF), Cepheids: Theory and Observations, Proceedings of IAU Colloquium No. 82, held 29 May - 1 June 1984 in Toronto, Canada (82) (New York: Cambridge University Press), June 1985, (82): 98 [2022-06-30], Bibcode:1985cto..conf...98G.
- Sanwal, N. B.; Parthasarathy, M., UBV photometry of EU Tau., Astronomy and Astrophysics Supplement Series, January 1974, 13: 91–97, Bibcode:1974A&AS...13...91S.
