zh %E6%B0%B4%E4%BD%8D%E4%B8%89

**水位三（巨蟹座8）**
觀測資料; 曆元 J2000
星座	巨蟹座
星官	水位（鬼宿）
赤經	08h 05m 04.48834s
赤緯	+13° 07′ 05.5757″
視星等（V）	+5.14
特性
光谱分类	A1 V
B−V 色指数	0.018±0.005
天体测定
徑向速度 (Rv)	+21.0±4.2 km/s
自行 (μ)	赤经：−35.78 mas/yr ; 赤纬：−63.81 mas/yr
视差 (π)	15.20 ± 0.32 mas
距离	215 ± 5 ly ; (66 ± 1 pc)
绝对星等 (MV)	1.05
詳細資料
質量	2.37 M☉
表面重力 (log g)	4.29±0.14
亮度	36.6 L☉
溫度	10,352±352 K
自轉速度 (v sin i)	173 km/s
年齡	144 Myr
其他命名
	8 Cnc、BD+13°1831、FK5 2625、GC 10959、HD 66664、HIP 39567、HR 3163、SAO 97542
參考資料庫
SIMBAD	资料

水位三也稱為巨蟹座8，是在黃道星座巨蟹座的一顆白色調的恆星^[7]。它的視星等為+5.14^[2]，這表明在適當的觀看條件下，肉眼可以看到這顆黯淡的恆星。根據其每年15.20mas的視差偏移，確定到這顆恒星的距離^[1]大約是215光年。+21公里/秒的徑向速度表明它正在遠離太陽^[4]。

這是一顆A型主序星，其恆星分類為A1V^[3]。這是一顆年輕的恒星，估計年齡只有1億4400萬年^[5]，並且具有173公里/秒的投影旋轉速度的高自旋率^[5]。水位三的質量是2.37倍的太陽質量^[5]，和從光球層以10,352K的有效溫度 ^[5]輻射出36.6倍太陽光度^[2]。

參考資料

^ ^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, S2CID 18759600, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.
^ ^2.0 ^2.1 ^2.2 ^2.3 ^2.4 ^2.5 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 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, S2CID 59451347, arXiv:1208.3048 , doi:10.1051/0004-6361/201219219, A61.
^ ^5.0 ^5.1 ^5.2 ^5.3 ^5.4 ^5.5 ^5.6 ^5.7 ^5.8 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.
^ 8 Cnc. SIMBAD. 斯特拉斯堡天文資料中心.
^ 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 .

[vanLeeuwen2007-1] 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, S2CID 18759600, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357.

[Anderson2012-2] 2.0 ^2.1 ^2.2 ^2.3 ^2.4 ^2.5 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.

[Cowley1969-3] 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.

[deBruijne2012-4] 4.0 ^4.1 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, S2CID 59451347, arXiv:1208.3048 , doi:10.1051/0004-6361/201219219, A61.

[David2015-5] 5.0 ^5.1 ^5.2 ^5.3 ^5.4 ^5.5 ^5.6 ^5.7 ^5.8 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.

[SIMBAD-6] 8 Cnc. SIMBAD. 斯特拉斯堡天文資料中心.

[Eggleton2008-7] 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 .

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