金牛座SZ

金牛座SZ是位於黃道星座金牛座的一顆變星。這顆恆星的亮度接近肉眼可見的下限,以3.149天的週期,在視星等6.39等到6.69星等之間變化[3]。根據視差的量測,到這顆恆星的距離約為2,070光年[2]。有跡象表明這可能是一顆聯星系統,但證據並不確定[14]

金牛座SZ

依據凌日系外行星巡天衛星(TESS)
的數據,繪製的金牛座SZ光變曲線[1]
觀測資料
曆元 J2000.0
星座 金牛座
星官
赤經 04h 37m 14.778s[2]
赤緯 +18° 32′ 34.93″[2]
視星等(V) 6.39 to 6.69[3]
特性
演化階段超巨星
光譜分類F5Ib-F9.5Ib[4]
B−V 色指數0.810+0.025
[5]
變星類型仙王座δ[6]
天體測定
徑向速度 (Rv)−1.2+0.2
[7] km/s
自行 (μ) 赤經:−4.403 mas/yr
赤緯:−5.232 mas/yr
視差 (π)1.5741 ± 0.028[2] mas
距離2,070 ± 40 ly
(640 ± 10 pc)
詳細資料
質量6.1+0.8
[8] M
半徑42.2+3.0
[9] R
表面重力 (log g)2.0–2.2[10]
亮度1,905[11] L
溫度6,015–6,420[11] K
金屬量 [Fe/H]0.08[10] dex
年齡69–80[12] Myr
其他命名
SZ Tau、​BD+18 661、​GC 5621、​HD 29260、​HIP 21517、​SAO 94036、​PPM 120081[13]
參考資料庫
SIMBAD資料

這顆恆星的可變性是由卡爾·史瓦西(英語:Karl Schwarzschild)在1911年宣佈的,起初被命名為41.1910,週期為3.1484 d[15][16]勒維特(英語:Henrietta Swan Leavitt)將這項研究持續到1914年,產生了一個週期為3.1487 d光變曲線[17]。1916年,H.沙普利(英語:Harlow Shapley)的一項光譜研究表明,造父變星的這種恆星脈動英語Stellar pulsation使恆星分類的類型沿着光變曲線變化,從光度最低的F7到最高的A9[18]尤裏·尼古拉耶維奇·埃夫雷莫夫英語Yuri Nicolaevich Efremov在1964年提出,這顆恆星位於疏散星團NGC 1647的東北方2.2°,可能是其暈成員[19]。然而,後來因為自行不能吻合而,因而引起爭議[20]。它在1985年被沃爾夫岡·吉倫英語Wolfgang Gieren確認為經典造父變星 [21]

變星總表中,金牛座SZ被歸類為DCEPS型的仙王座δ型變星,它顯示出一條幾乎對稱的小振幅光變曲線[6]。它在第一個泛音中脈動[19],並且在演化方面,正在經歷第二次穿越造父變星的不穩定帶[12]。到1987年,已經觀察到金牛座SZ脈動週期的四次變化[22];脈動頻率每年減少-0.49 秒[12]。這顆星的年齡大約是7,500萬年[12],質量是太陽的6倍[8],半徑是太陽的42倍[9]。恆星的有效溫度、半徑和光譜類型在每個脈動週期中都會變化[11]

參考資料

  1. ^ 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). 
  2. ^ 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. ^ 3.0 3.1 Klagyivik, P.; Szabados, L., Observational studies of Cepheid amplitudes. I. Period-amplitude relationships for Galactic Cepheids and interrelation of amplitudes, Astronomy and Astrophysics, September 2009, 504 (3): 959–972, Bibcode:2009A&A...504..959K, S2CID 18283579, arXiv:0908.3561 , doi:10.1051/0004-6361/200811464. 
  4. ^ Kraft, Robert P., Color Excesses for Supergiants and Classical Cepheids. I. Calibration of the Gband Photometry, Astrophysical Journal, March 1960, 131: 330, Bibcode:1960ApJ...131..330K, doi:10.1086/146837. 
  5. ^ 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. 
  6. ^ 6.0 6.1 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. 
  7. ^ 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. 
  8. ^ 8.0 8.1 Marconi, Marcella; et al, Predicted Masses of Galactic Cepheids in the Gaia Data Release 2, The Astrophysical Journal Letters, July 2020, 898 (1): L7, Bibcode:2020ApJ...898L...7M, S2CID 220265392, arXiv:2006.16610 , doi:10.3847/2041-8213/aba12b, L7. 
  9. ^ 9.0 9.1 Postma, Joseph E.; Milone, E. F., Observations and Analyses of the Cepheid SZ Tauri, Bulletin of the American Astronomical Society, June 2006, 38: 144, Bibcode:2006AAS...208.6506P. 
  10. ^ 10.0 10.1 Andrievsky, S. M.; et al, Barium abundances in Cepheids, Monthly Notices of the Royal Astronomical Society, 2013, 428 (4): 3252, Bibcode:2013MNRAS.428.3252A, arXiv:1210.6211 , doi:10.1093/mnras/sts270 . 
  11. ^ 11.0 11.1 11.2 Sanwal, B. B.; Rautela, B. S., Spectrophotometric Study of the Cepheids DT-Cygni and SZ-Tauri, Astrophysics and Space Science, January 1989, 151 (2): 209–215, Bibcode:1989Ap&SS.151..209S, S2CID 119557969, doi:10.1007/BF00648379. 
  12. ^ 12.0 12.1 12.2 12.3 Fadeyev, Yu. A., Evolution, pulsation and period change in the Cepheid SZ Tau, Astronomy Letters, November 2015, 41 (11): 640–645, Bibcode:2015AstL...41..640F, S2CID 255192877, arXiv:1507.04715 , doi:10.1134/S1063773715110031. 
  13. ^ SZ Tau. SIMBAD. 斯特拉斯堡天文資料中心. 
  14. ^ Kervella, Pierre; et al, Multiplicity of Galactic Cepheids and RR Lyrae stars from Gaia DR2. II. Resolved common proper motion pairs, Astronomy & Astrophysics, March 2019, 623: 40, Bibcode:2019A&A...623A.117K, arXiv:1908.00545 , doi:10.1051/0004-6361/201834211, A117. 
  15. ^ Schwarzschild, Karl, Über den Lichtwechsel des Veränderlichen 41.1910 Tauri, Astronomische Nachrichten, October 1911, 189 (20): 345–356 [2023-08-14], Bibcode:1911AN....189..345S, doi:10.1002/asna.2101892002, (原始內容存檔於2023-08-14) (德語). 
  16. ^ Shapley, H., Concerning the ellipsoidal variables SZ Tauri and S Antliae, Astronomische Nachrichten, May 1913, 194 (21): 353–359 [2023-08-14], Bibcode:1913AN....194..353S, doi:10.1002/asna.19131942102, (原始內容存檔於2023-08-14). 
  17. ^ Leavitt, Henrietta S.; Pickering, Edward C., Observations of SZ Tauri, Harvard College Observatory Circular, November 1914, 186: 1–4, Bibcode:1914HarCi.186....1L. 
  18. ^ Shapley, H., The variations in spectral type of twenty Cepheid variables, Astrophysical Journal, December 1916, 44: 273–291, Bibcode:1916ApJ....44..273S, doi:10.1086/142295. 
  19. ^ 19.0 19.1 Turner, David G., Galactic Clusters With Associated Cepheid Variables. III. NGC 1647 and SZ Tauri, Astronomical Journal, November 1992, 104: 1865 [2023-08-14], Bibcode:1992AJ....104.1865T, doi:10.1086/116363, (原始內容存檔於2023-08-14). 
  20. ^ Baumgardt, H.; et al, Absolute proper motions of open clusters. I. Observational data, Astronomy and Astrophysics Supplement, October 2000, 146 (2): 251–258, Bibcode:2000A&AS..146..251B, S2CID 7180188, arXiv:astro-ph/0010306 , doi:10.1051/aas:2000362. 
  21. ^ Gieren, W. P., Physical properties of the cepheids RT Aurigae and SZ Tauri, Astronomy and Astrophysics, July 1985, 148: 138–144, Bibcode:1985A&A...148..138G. 
  22. ^ Trammell, Susan R., The Changing Period of SZ Tauri, The Journal of the American Association of Variable Star Observers, December 1987, 16 (2): 104–106, Bibcode:1987JAVSO..16..104T.