海石四
海石四(HD 84810)，也称为船底座l (l Car)，是位于南天船底座的一颗恒星。它的平均视星等是 +3.4,[3]，使它成为船底座较亮，并且以肉眼很容易见到。依据视差测量，它距离地球大约1600光年[2]。
| 观测资料 历元 J2000.0 | |
|---|---|
| 星座 | 船底座 |
| 星官 | |
| 赤经 | 09h 45m 14.81122s[2] |
| 赤纬 | –62° 30′ 28.4519″[2] |
| 视星等（V） | 3.39[3] |
| 特性 | |
| 光谱分类 | G5 Iab/Ib[4] |
| U−B 色指数 | +0.76[3] |
| B−V 色指数 | +1.03[3] |
| 变星类型 | 经典造父变星 |
| 天体测定 | |
| 径向速度 (Rv) | +3.3[5] km/s |
| 自行 (μ) | 赤经：–12.88[2] mas/yr 赤纬：+8.19[2] mas/yr |
| 视差 (π) | 2.09 ± 0.29[2] mas |
| 距离 | approx. 1,600 ly (approx. 480 pc) |
| 详细资料 | |
| 质量 | 8.4[4] to 13[6] M☉ |
| 半径 | 169±8[7] R☉ |
| 表面重力 (log g) | 1.5[8] |
| 温度 | 5,091[8] K |
| 金属量 [Fe/H] | 0.30[8] dex |
| 年龄 | 33.3±5.9[4] Myr |
| 其他命名 | |
船底座l的光谱类型是G5 Iab/Ib[4]，从它的光谱特征，表明了这颗恒星在演化阶段显示已经膨胀成为一颗超巨星，半径是太阳的169倍[7]。如果它的质量8倍于太阳[4]–13[6]，在主序星经历了大约1,500-1,700万年[6]，通过燃烧核心供应的核燃料，大约在3,300万年就会快速的成为超巨星[4]。
船底座l在分类上是一颗造父变星，它的变光幅度是0.725等，周期为35.560天。在每一个脉动周期中径向速度的改变一致都是39公里/秒[9]。使用干涉仪可以分辨出它有一个紧密的拱星环壳层。使用波长10微米的红外线可以解析这个壳层，显示在半径10-100AU处的平均温度是100K。这个壳层中的物质是由中心恒星喷发的物质供应[6]。
参考资料
- ^ SIMBAD, "l Carinae", December 30, 2010
- ^ 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.
- ^ 3.0 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.
- ^ 4.0 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.
- ^ Evans, D. S., Batten, Alan Henry; Heard, John Frederick , 编, 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.
- ^ 6.0 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.
- ^ 7.0 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.
- ^ 8.0 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.
- ^ 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.
