水位二
水位二也称为小犬座11是在赤道星座小犬座 [7]的一颗恒星[8]，距离太阳约313光年[1]。它是一颗肉眼可见的微弱白色恒星，视星等为+5.25[2]。它正以相对于日心+28公里/秒的径向速度远离地球[4]，大约235万年前的距离在157光年以内[2]。
| 观测资料 历元 J2000.0 (ICRS) | |
|---|---|
| 星座 | 小犬座 |
| 星官 | 水位（鬼宿） |
| 赤经 | 07h 46m 16.20081s[1] |
| 赤纬 | +10° 46′ 05.7055″[1] |
| 视星等（V） | 5.25[2] |
| 特性 | |
| 光谱分类 | A1Vnn[3] |
| B−V 色指数 | 0.018±0.008[2] |
| 天体测定 | |
| 径向速度 (Rv) | +28.0±4.2[4] km/s |
| 自行 (μ) | 赤经：−29.902[1] mas/yr 赤纬：−25.275[1] mas/yr |
| 视差 (π) | 10.4262 ± 0.2007[1] mas |
| 距离 | 313 ± 6 ly (96 ± 2 pc) |
| 绝对星等 (MV) | 0.42[2] |
| 详细资料 | |
| 质量 | 2.23[5] M☉ |
| 半径 | 2.5[6] R☉ |
| 表面重力 (log g) | 3.60[5] |
| 亮度 | 65.26[2] L☉ |
| 温度 | 9,972±339[5] K |
| 年龄 | 149[5] Myr |
| 其他命名 | |
| 参考数据库 | |
| SIMBAD | 资料 |
这是一颗A型主序星，其恒星分类为A1Vnn[3]，其中的符号“n”表示由于快速旋转而导致的（非常）“模糊”线。然而，Gray和Garrison（1987）发现了一个A0.5Ivnn的分类[9]，这将与一颗演化的次巨星相匹配。这是一颗未知类型的可疑变星[10]。它的年龄为1亿4900万年[5]，质量是2.23倍太阳质量[5]，半径是2.5倍太阳半径[6]。它以9,972K的有效温度[5]从光球层辐射65倍的太阳光度[2]
参考资料
- ^ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A.; Vallenari, A.; Prusti, T.; de Bruijne, J. H. J.; et al. Gaia Data Release 2. Summary of the contents and survey properties. Astronomy & Astrophysics. 2018. Bibcode:2018A&A...616A...1G. arXiv:1804.09365
. doi:10.1051/0004-6361/201833051. VizieR中此天体在盖亚望远镜第二批数据发布的记录
- ^ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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 Cowley, A.; et al, A study of the bright A stars. I. A catalogue of spectral classifications, Astronomical Journal, April 1969, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- ^ 4.0 4.1 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.
- ^ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 David, Trevor J.; Hillenbrand, Lynne A., The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets, The Astrophysical Journal, 2015, 804 (2): 146, Bibcode:2015ApJ...804..146D, S2CID 33401607, arXiv:1501.03154 , doi:10.1088/0004-637X/804/2/146.
- ^ 6.0 6.1 Pasinetti Fracassini, L. E.; et al, Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS), Astronomy and Astrophysics Third, February 2001, 367 (2): 521–524, Bibcode:2001A&A...367..521P, S2CID 425754, arXiv:astro-ph/0012289 , doi:10.1051/0004-6361:20000451.
- ^ 7.0 7.1 11 CMi. SIMBAD. 斯特拉斯堡天文资料中心.
- ^ Eggleton, P. P.; Tokovinin, A. A., A catalogue of multiplicity among bright stellar systems, Monthly Notices of the Royal Astronomical Society, September 2008, 389 (2): 869–879, Bibcode:2008MNRAS.389..869E, S2CID 14878976, arXiv:0806.2878 , doi:10.1111/j.1365-2966.2008.13596.x .
- ^ Gray, R. O.; Garrison, R. F., The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation, Astrophysical Journal Supplement, December 1987, 65: 581, Bibcode:1987ApJS...65..581G, doi:10.1086/191237 .
- ^ 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.
