小獅座21是在星座小獅座的一顆恆星。它的視星等大約是4.5等,黯淡的亮度使肉眼不易看見(參見波特爾暗空分類法)。由依巴谷衛星量測的視差估計,它距離地球大約92.1光年(28.2秒差距[1]。它被認為是天狼星超級星團的一員[6]

小獅座21
觀測資料
曆元 J2000
星座 小獅座
星官
赤經 10h 07m 25.76296s[1]
赤緯 +35° 14′ 40.8965″[1]
視星等(V) 4.47–4.52[2]
特性
光譜分類A7V[3]
U−B 色指數+0.08[4]
B−V 色指數+0.18[4]
變星類型δ Sct[2]
天體測定
徑向速度 (Rv)−11.40 ± 0.9[5] km/s
自行 (μ) 赤經:52.90[1] mas/yr
赤緯:0.62[1] mas/yr
視差 (π)35.41 ± 0.18[1] mas
距離92.1 ± 0.5 ly
(28.2 ± 0.1 pc)
絕對星等 (MV)+2.43[6]
詳細資料
質量1.75[7] M
半徑1.75[7] R
表面重力 (log g)4.07[8]
亮度9.91[7] L
溫度7,839[8] K
金屬量 [Fe/H]0.03±0.08[7] dex
自轉速度 (v sin i)155[9] km/s
年齡390[9] Myr
750[7] Myr
其他命名
21 LMi、​BD+35°2110、​GJ 378.3, 9314、​HD 87696、​HIP 49593、​HR 3974、​SAO 61874[10]
參考資料庫
SIMBAD資料

小獅座21的旋轉速度相當快,它的投影旋轉速度估計為155公里/秒[9],所以它的自轉至少得有那麼快。它被列為光譜類型A7V的的快速旋轉光譜標準星,而不是緩慢旋轉的標準星長蛇座2[11]。它也是盾牌座δ型變星視星等在4.47至4.52之間變動[2]

小獅座21有紅外過量,因此認為在它的周圍有一個岩屑盤[9]黑體擬合的溫度為60 K,軌道半徑為62 AU[7]

參考資料

  1. ^ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F.; et al. Validation of the new Hipparcos reduction. Astronomy and Astrophysics. 2007, 474 (2): 653–664 [2023-05-10]. Bibcode:2007A&A...474..653V. S2CID 18759600. arXiv:0708.1752 . doi:10.1051/0004-6361:20078357. (原始內容存檔於2019-12-07). 
  2. ^ 2.0 2.1 2.2 Samus, N. N.; Durlevich, O. V.; et al. VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013). VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 2009, 1. Bibcode:2009yCat....102025S. 
  3. ^ Johnson, H. L.; Morgan, W. W. Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas. The Astrophysical Journal. 1953, 117: 313. Bibcode:1953ApJ...117..313J. doi:10.1086/145697. 
  4. ^ 4.0 4.1 Johnson, H. L. UBVRIJKL Photometry of the Bright Stars. Communications of the Lunar and Planetary Laboratory. 1966, 4: 99. Bibcode:1966CoLPL...4...99J. 
  5. ^ Gontcharov, G. A. Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system. Astronomy Letters. 2006, 32 (11): 759–771. Bibcode:2006AstL...32..759G. S2CID 119231169. arXiv:1606.08053 . doi:10.1134/S1063773706110065. 
  6. ^ 6.0 6.1 Eggen, Olin J., The Sirius Supercluster and Missing Mass near the Sun, The Astronomical Journal, August 1998, 116 (2): 782–788, Bibcode:1998AJ....116..782E, doi:10.1086/300465 . 
  7. ^ 7.0 7.1 7.2 7.3 7.4 7.5 Gáspár, András; et al, The Correlation between Metallicity and Debris Disk Mass, The Astrophysical Journal, 2016, 826 (2): 171, Bibcode:2016ApJ...826..171G, S2CID 119241004, arXiv:1604.07403 , doi:10.3847/0004-637X/826/2/171. 
  8. ^ 8.0 8.1 Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I. The Astronomical Journal. 2003, 126 (4): 2048. Bibcode:2003AJ....126.2048G. S2CID 119417105. arXiv:astro-ph/0308182 . doi:10.1086/378365. 
  9. ^ 9.0 9.1 9.2 9.3 Rieke, G. H.; Su, K. Y. L.; Stansberry, J. A.; Trilling, D.; Bryden, G.; Muzerolle, J.; White, B.; Gorlova, N.; Young, E. T.; Beichman, C. A.; Stapelfeldt, K. R.; Hines, D. C. Decay of Planetary Debris Disks. The Astrophysical Journal. 2005, 620 (2): 1010. Bibcode:2005ApJ...620.1010R. CiteSeerX 10.1.1.579.8956 . S2CID 54676993. doi:10.1086/426937. 
  10. ^ * 21 LMi. SIMBAD. 斯特拉斯堡天文資料中心. 
  11. ^ Gray, R. O.; Garrison, R. F. The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation. The Astrophysical Journal Supplement Series. 1989, 70: 623. Bibcode:1989ApJS...70..623G. doi:10.1086/191349.