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**明堂一（τ Leo）**
觀測資料; 曆元 J2000.0（ICRS)
星座	獅子座
星官
赤經	11h 27m 56.23976s
赤緯	+02° 51′ 22.5609″
視星等（V）	5.00
特性
光谱分类	G8- IIIa
U−B 色指数	+0.80
B−V 色指数	+1.005
天体测定
徑向速度 (Rv)	−8.90 km/s
自行 (μ)	赤经：+16.89 mas/yr ; 赤纬：−9.81 mas/yr
视差 (π)	5.80 ± 0.33 mas
距离	560 ± 30 ly ; (172 ± 10 pc)
绝对星等 (MV)	−1.12±0.124
詳細資料
質量	3.90±0.19 M☉
半徑	25.14±1.55 R☉
表面重力 (log g)	2.25±0.05
亮度	329.6±39.6 L☉
溫度	4,910±33 K
金属量 [Fe/H]	−0.07±0.10 dex
年齡	190±20 Myr
其他命名
	τ Leo、84 Leo、 BD+03°2504、FK5 1297、HD 99648、HIP 55945、HR 4418, SAO 118875
參考資料庫
SIMBAD	资料

明堂一（τ Leo）是黃道星座獅子座中的一顆恆星。因為它位於黃道附近，所以它會被月球掩蔽，發生月掩星的事件^[8]。它的視星等為5.00^[2]，其亮度足以用肉眼看到。使用視差測量值估計到這顆恒星的距離^[1]是560光年。它以− 9公里/秒的徑向速度朝向太陽移動^[4]。

這是顆G型的巨星，恒星分類為G8IIIa ^[3]，現時位於赫羅圖的紅巨星分支。它的質量約為太陽質量的390%。這顆恒星比太陽年輕得多，年齡約為1.9億年。做為一顆演化的巨星，它已經膨脹到約太陽半徑的25倍，輻射量是太陽光度的330倍。外大氣層的有效溫度為4910K^[6]。

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^ ^2.0 ^2.1 ^2.2 ^2.3 Mermilliod, J.-C., Compilation of Eggen's UBV data, transformed to UBV (unpublished), Catalogue of Eggen's UBV Data (SIMBAD), 1986, Bibcode:1986EgUBV........0M.
^ ^3.0 ^3.1 Keenan, P.; McNeil, R., The Perkins catalog of revised MK types for the cooler stars, Astrophysical Journal Supplement Series, October 1989, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
^ ^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.
^ Park, Sunkyung; et al, Wilson-Bappu Effect: Extended to Surface Gravity, The Astronomical Journal, 2013, 146 (4): 73, Bibcode:2013AJ....146...73P, S2CID 119187733, arXiv:1307.0592 , doi:10.1088/0004-6256/146/4/73.
^ ^6.0 ^6.1 ^6.2 ^6.3 ^6.4 ^6.5 ^6.6 ^6.7 Hekker, S.; Meléndez, J., Precise radial velocities of giant stars. III. Spectroscopic stellar parameters, Astronomy and Astrophysics, 2007, 475 (3): 1003–1009, Bibcode:2007A&A...475.1003H, S2CID 10436552, arXiv:0709.1145 , doi:10.1051/0004-6361:20078233.
^ * tau Leo. SIMBAD. 斯特拉斯堡天文資料中心. [2016-09-29].
^ Richichi, A.; et al, Further Lunar Occultations from the 2.4 m Thai National Telescope, The Astronomical Journal, December 2017, 154 (6): 4, Bibcode:2017AJ....154..215R, doi:10.3847/1538-3881/aa9068, 215.

[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.

[Mermilliod1986-2] 2.0 ^2.1 ^2.2 ^2.3 Mermilliod, J.-C., Compilation of Eggen's UBV data, transformed to UBV (unpublished), Catalogue of Eggen's UBV Data (SIMBAD), 1986, Bibcode:1986EgUBV........0M.

[Keenan1989-3] 3.0 ^3.1 Keenan, P.; McNeil, R., The Perkins catalog of revised MK types for the cooler stars, Astrophysical Journal Supplement Series, October 1989, 71: 245–266, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.

[aa546_A61-4] 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.

[park2013-5] Park, Sunkyung; et al, Wilson-Bappu Effect: Extended to Surface Gravity, The Astronomical Journal, 2013, 146 (4): 73, Bibcode:2013AJ....146...73P, S2CID 119187733, arXiv:1307.0592 , doi:10.1088/0004-6256/146/4/73.

[Hekker2007-6] 6.0 ^6.1 ^6.2 ^6.3 ^6.4 ^6.5 ^6.6 ^6.7 Hekker, S.; Meléndez, J., Precise radial velocities of giant stars. III. Spectroscopic stellar parameters, Astronomy and Astrophysics, 2007, 475 (3): 1003–1009, Bibcode:2007A&A...475.1003H, S2CID 10436552, arXiv:0709.1145 , doi:10.1051/0004-6361:20078233.

[SIMBAD-7] * tau Leo. SIMBAD. 斯特拉斯堡天文資料中心. [2016-09-29].

[Richichi2017-8] Richichi, A.; et al, Further Lunar Occultations from the 2.4 m Thai National Telescope, The Astronomical Journal, December 2017, 154 (6): 4, Bibcode:2017AJ....154..215R, doi:10.3847/1538-3881/aa9068, 215.

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明堂一

參考資料

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