海石四(HD 84810),也稱為船底座l (l Car),是位於南天船底座的一顆恆星。它的平均視星等是 +3.4,[3],使它成為船底座較亮,並且以肉眼很容易見到。依據視差測量,它距離地球大約1600光年[2]

船底座l [1]
觀測資料
曆元 J2000.0
星座 船底座
星官
赤經 09h 45m 14.81122s[2]
赤緯 –62° 30′ 28.4519″[2]
視星等(V) 3.39[3]
特性
光譜分類G5 Iab/Ib[4]
U−B 色指數+0.76[3]
B−V 色指數+1.03[3]
變星類型經典造父變星
天體測定
徑向速度 (Rv)+3.3[5] km/s
自行 (μ) 赤經:–12.88[2] mas/yr
赤緯:+8.19[2] mas/yr
視差 (π)2.09 ± 0.29[2] mas
距離approx. 1,600 ly
(approx. 480 pc)
詳細資料
質量8.4[4] to 13[6] M
半徑169±8[7] R
表面重力 (log g)1.5[8]
溫度5,091[8] K
金屬量 [Fe/H]0.30[8] dex
年齡33.3±5.9[4] Myr
其他命名
船底座l 2MASS J09451481-6230284, CD–61 2349, FK5 1254, HD 84810, HIP 47854, HR 3884, IRAS 09438-6216, SAO 250683.

船底座l的光譜類型是G5 Iab/Ib[4],從它的光譜特徵,表明了這顆恆星在演化階段顯示已經膨脹成為一顆超巨星,半徑是太陽的169倍[7]。如果它的質量8倍於太陽[4]–13[6],在主序星經歷了大約1,500-1,700萬年[6],通過燃燒核心供應的核燃料,大約在3,300萬年就會快速的成為超巨星[4]

船底座l在分類上是一顆造父變星,它的變光幅度是0.725等,週期為35.560天。在每一個脈動週期中徑向速度的改變一致都是39公里/秒[9]。使用干涉儀可以分辨出它有一個緊密的拱星環殼層。使用波長10微米的紅外線可以解析這個殼層,顯示在半徑10-100AU處的平均溫度是100K。這個殼層中的物質是由中心恆星噴發的物質供應[6]

參考資料

  1. ^ SIMBAD, "l Carinae", December 30, 2010
  2. ^ 2.0 2.1 2.2 2.3 2.4 2.5 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  3. ^ 3.0 3.1 3.2 3.3 Madore, B. F., Photoelectric UBV photometry of Cepheids in the Magellanic Clouds and in the southern Milky Way, Astrophysical Journal Supplement Series, June 1975, 29: 219–284, Bibcode:1975ApJS...29..219M, doi:10.1086/190342. 
  4. ^ 4.0 4.1 4.2 4.3 4.4 4.5 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M., A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun, Monthly Notices of the Royal Astronomical Society, January 2011, 410 (1): 190–200, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x. 
  5. ^ Evans, D. S., Batten, Alan Henry; Heard, John Frederick , 編, The Revision of the General Catalogue of Radial Velocities, Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30 (University of Toronto: International Astronomical Union), June 20–24, 1966, 30: 57, Bibcode:1967IAUS...30...57E. 
  6. ^ 6.0 6.1 6.2 6.3 Kervella, P.; Mérand, A.; Gallenne, A., The circumstellar envelopes of the Cepheids ℓ Carinae and RS Puppis. Comparative study in the infrared with Spitzer, VLT/VISIR, and VLTI/MIDI, Astronomy and Astrophysics, 2009, 498 (2): 425–443, Bibcode:2009A&A...498..425K, S2CID 14541935, arXiv:0902.1588 , doi:10.1051/0004-6361/200811307. 
  7. ^ 7.0 7.1 Davis, J.; et al, Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer, Monthly Notices of the Royal Astronomical Society, April 2009, 394 (3): 1620–1630, Bibcode:2009MNRAS.394.1620D, doi:10.1111/j.1365-2966.2009.14433.x. 
  8. ^ 8.0 8.1 8.2 Luck, R. E., The chemical compositions of nine southern supergiant stars, Astrophysical Journal, Part 1, September 1979, 232: 797–806, Bibcode:1979ApJ...232..797L, doi:10.1086/157340. 
  9. ^ 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, doi:10.1051/0004-6361/200811464.