水位增六
水位增六（巨蟹座Mu2）是一顆單獨的黃色恆星[10]，位置在黃道星座的巨蟹座內。它是肉眼可見的恆星，視星等+5.30等[2]，依據從地球測得的周年視差42.94毫角秒[1]，這顆恆星與太陽的距離是76光年。水位增六將在60萬年後，以最接近的4.9 pc（16 ly）距離掠過太陽[11]。
| 觀測資料 曆元 J2000.0 | |
|---|---|
| 星座 | 巨蟹座 |
| 星官 | |
| 赤經 | 08h 07m 45.85574s[1] |
| 赤緯 | +21° 34′ 54.5441″[1] |
| 視星等（V） | +5.30[2] |
| 特性 | |
| 光谱分类 | G2 IV[3] |
| U−B 色指数 | +0.21[2] |
| B−V 色指数 | +0.63[2] |
| 天体测定 | |
| 徑向速度 (Rv) | −36.0±0.1[4] km/s |
| 自行 (μ) | 赤经：+23.00[1] mas/yr 赤纬：−66.42[1] mas/yr |
| 视差 (π) | 42.94 ± 0.30[1] mas |
| 距离 | 76.0 ± 0.5 ly (23.3 ± 0.2 pc) |
| 绝对星等 (MV) | +3.46[5] |
| 詳細資料 | |
| 質量 | 1.192+0.017 −0.016[6] M☉ |
| 半徑 | 1.82[7] R☉ |
| 表面重力 (log g) | 3.97±0.02[6] |
| 亮度 | 3.45[8] L☉ |
| 溫度 | 5,809±59[6] K |
| 金属量 [Fe/H] | 0.11[6] dex |
| 自轉速度 (v sin i) | 3.7±0.3[5] km/s |
| 年齡 | 5.64+0.35 −0.14[6] Gyr |
| 其他命名 | |
| 參考資料庫 | |
| SIMBAD | 资料 |
估計它的年齡是56億年，它已演化成G型次巨星，類型為C2IV。[3]。它的質量是1.2倍太陽質量[6]，和1.8倍的太陽半徑 [7]。 水位增六有相對較高的金屬量 – 天文學家所謂的金屬是除了氫和氦之外的其他元素，比太陽的豐度高出29% [6]。它的輻射量 太陽亮度的3.45倍3.45[8]，表面的有效溫度是5,809k[6]。
參考資料 编辑
- ^ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752
, doi:10.1051/0004-6361:20078357.
- ^ 2.0 2.1 2.2 2.3 Johnson, H. L.; et al, UBVRIJKL photometry of the bright stars, Communications of the Lunar and Planetary Laboratory, 1966, 4 (99), Bibcode:1966CoLPL...4...99J.
- ^ 3.0 3.1 Gray, R. O.; et al, Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I, The Astronomical Journal, July 2006, 132 (1): 161–170, Bibcode:2006AJ....132..161G, arXiv:astro-ph/0603770 , doi:10.1086/504637.
- ^ de Bruijne, J. H. J.; Eilers, A.-C., Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project, Astronomy & Astrophysics, October 2012, 546: 14, Bibcode:2012A&A...546A..61D, arXiv:1208.3048 , doi:10.1051/0004-6361/201219219, A61.
- ^ 5.0 5.1 Ammler-von Eiff, M.; Reiners, A., New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?, Astronomy & Astrophysics, June 2012, 542: 31, Bibcode:2012A&A...542A.116A, arXiv:1204.2459 , doi:10.1051/0004-6361/201118724, A116.
- ^ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Ramírez, I.; et al, Oxygen abundances in nearby FGK stars and the galactic chemical evolution of the local disk and halo, The Astrophysical Journal, February 2013, 764 (1): 78, Bibcode:2013ApJ...764...78R, arXiv:1301.1582 , doi:10.1088/0004-637X/764/1/78.
- ^ 7.0 7.1 Takeda, Genya; et al, Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog, The Astrophysical Journal Supplement Series, February 2007, 168 (2): 297–318, Bibcode:2007ApJS..168..297T, arXiv:astro-ph/0607235 , doi:10.1086/509763.
- ^ 8.0 8.1 McDonald, I.; et al, Fundamental Parameters and Infrared Excesses of Hipparcos Stars, Monthly Notices of the Royal Astronomical Society, 2012, 427 (1): 343–57, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037 , doi:10.1111/j.1365-2966.2012.21873.x.
- ^ mu.02 Cnc. SIMBAD. 斯特拉斯堡天文資料中心. [2017-06-17].
- ^ 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, arXiv:0806.2878 , doi:10.1111/j.1365-2966.2008.13596.x.
- ^ Bailer-Jones, C. A. L., Close encounters of the stellar kind, Astronomy & Astrophysics, March 2015, 575: 13, Bibcode:2015A&A...575A..35B, arXiv:1412.3648 , doi:10.1051/0004-6361/201425221, A35.
