势四

**勢四（小獅座46）**
	勢四的位置（紅圈處）
觀測資料; 曆元 J2000
星座	小獅座
星官	勢（紫微垣）
赤經	10h 53m 18.70487s
赤緯	+34° 12′ 53.5375″
視星等（V）	3.83 (3.79–3.84)
特性
光谱分类	K0+ III-IV
天体测定
自行 (μ)	赤经：+92.02 mas/yr ; 赤纬：–285.82 mas/yr
视差 (π)	34.38 ± 0.21 mas
距离	94.9 ± 0.6 ly ; (29.1 ± 0.2 pc)
绝对星等 (MV)	+1.45
詳細資料
質量	1.69 M☉
半徑	8.22 ± 0.22 R☉
表面重力 (log g)	2.96
亮度	34 ± 2 L☉
溫度	4,670 K
金属量 [Fe/H]	−0.20 dex
自轉速度 (v sin i)	1.81 km/s
年齡	6.76 Gyr
其他命名
	Praecipua、46 LM、BD+34 2172、FK5 412、HD 94264、HIP 53229, HR 4247、SAO 62297
參考資料庫
SIMBAD	资料

勢四（英語：Praecipua，/prɪˈsɪpjʊə/^[10]，小獅座46，46 LMi）是小獅座最亮的恆星。它的視星等為3.83等，光譜類型為K0+III-IV，是在紅團簇星中的一顆巨星^[9]。依據視差的測量，它與太陽的距離約為95光年。它疑似為變星，振幅僅有0.05星等^[3]。

命名法

小獅座46的名稱來自佛蘭斯蒂德命名法。它有時會依據1801年弗朗西斯·貝利的星表，標示為小獅座o（不是ο）。合理的推測認為它在拜耳命名法中是α星，但是貝利決定在他的星表中標示每一顆比4.5等亮的恆星時，錯誤的將α寫成o，所以小獅座有較暗的β星(勢增四，視星等4.2等)，卻沒有最亮的α星^[11]。

它的傳統名稱是Praecipua，這是源自拉丁文的名稱，意思是「首領」（小獅座為首的恆星）^[12]。這個名字最初可能是指勢增十一（小獅座37，視星等4.7），後來被錯誤的轉移到了這顆恆星上^[13]。在2016年，國際天文學聯合會（IAU）組織的IAU恆星名稱工作組（WGSN）^[14]，對恆星的專有名稱進行分類和標準化。WGSN於2017年6月30日核定了這顆恆星的名稱為Praecipua，並將其列入IAU核定的恒星名稱清單中^[10]。

勢四是中國的名稱，意思是星官勢的第四顆星。在傳統的中國天文學體系中屬於紫微垣。

參考資料

^ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 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 Piau, L.; et al, Surface convection and red-giant radius measurements, Astronomy and Astrophysics, February 2011, 526: A100, Bibcode:2011A&A...526A.100P, S2CID 118533297, arXiv:1010.3649 , doi:10.1051/0004-6361/201014442
^ ^3.0 ^3.1 Samus, N. N.; Durlevich, O. V.; et al. VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013). VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 2009, 1. Bibcode:2009yCat....102025S.
^ Keenan, Philip C.; McNeil, Raymond C. The Perkins catalog of revised MK types for the cooler stars. Astrophysical Journal Supplement Series. 1989, 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
^ Mullan, D. J.; MacDonald, J. Onset of Mass Loss in Red Giants: Association with an Evolutionary Event. The Astrophysical Journal. 2003, 591 (2): 1203. Bibcode:2003ApJ...591.1203M. doi:10.1086/375446 .
^ Lyubimkov, L. S.; Poklad, D. B. Determining the effective temperatures of G- and K-type giants and supergiants based on observed photometric indices. Kinematics and Physics of Celestial Bodies. 2014, 30 (5): 244. Bibcode:2014KPCB...30..244L. S2CID 118618820. arXiv:1412.6950 . doi:10.3103/S0884591314050055.
^ Wittenmyer, Robert A.; Gao, Dongyang; Hu, Shao Ming; Villaver, Eva; Endl, Michael; Wright, Duncan. The Weihai Observatory Search for Close-in Planets Orbiting Giant Stars. Publications of the Astronomical Society of the Pacific. 2015, 127 (956): 1021. Bibcode:2015PASP..127.1021W. S2CID 117305333. arXiv:1507.06051 . doi:10.1086/683258.
^ Hekker, S.; Meléndez, J. Precise radial velocities of giant stars. III. Spectroscopic stellar parameters. Astronomy and Astrophysics. 2007, 475 (3): 1003. Bibcode:2007A&A...475.1003H. S2CID 10436552. arXiv:0709.1145 . doi:10.1051/0004-6361:20078233.
^ ^9.0 ^9.1 Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants. Astronomy and Astrophysics. 2008, 480 (1): 91–101. Bibcode:2008A&A...480...91S. S2CID 16602121. arXiv:0712.1370 . doi:10.1051/0004-6361:20078788.
^ ^10.0 ^10.1 Naming Stars. IAU.org. [2017-12-16]. （原始内容存档于2020-04-11）.
^ Wagman, Morton. Lost Stars. Blacksburg, Virginia: McDonald and Woodward. 2003. ISBN 0-939923-78-5.
^ Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York, NY: Dover Publications Inc. 1963: 264. ISBN 0-486-21079-0.
^ Leo Minor: The little lion （页面存档备份，存于互联网档案馆）- Ian Ridpath's Star Tales
^ IAU Working Group on Star Names (WGSN). [2016-05-22]. （原始内容存档于2019-06-26）.

[aaa474_2_653-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 van Leeuwen, F., Validation of the new Hipparcos reduction, Astronomy and Astrophysics, November 2007, 474 (2): 653–664, Bibcode:2007A&A...474..653V, S2CID 18759600, arXiv:0708.1752 , doi:10.1051/0004-6361:20078357

[aaa526_A100-2] 2.0 ^2.1 ^2.2 ^2.3 ^2.4 Piau, L.; et al, Surface convection and red-giant radius measurements, Astronomy and Astrophysics, February 2011, 526: A100, Bibcode:2011A&A...526A.100P, S2CID 118533297, arXiv:1010.3649 , doi:10.1051/0004-6361/201014442

[gcvs-3] 3.0 ^3.1 Samus, N. N.; Durlevich, O. V.; et al. VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013). VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 2009, 1. Bibcode:2009yCat....102025S.

[perkins-4] Keenan, Philip C.; McNeil, Raymond C. The Perkins catalog of revised MK types for the cooler stars. Astrophysical Journal Supplement Series. 1989, 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.

[mullen-5] Mullan, D. J.; MacDonald, J. Onset of Mass Loss in Red Giants: Association with an Evolutionary Event. The Astrophysical Journal. 2003, 591 (2): 1203. Bibcode:2003ApJ...591.1203M. doi:10.1086/375446 .

[lyubimkov-6] Lyubimkov, L. S.; Poklad, D. B. Determining the effective temperatures of G- and K-type giants and supergiants based on observed photometric indices. Kinematics and Physics of Celestial Bodies. 2014, 30 (5): 244. Bibcode:2014KPCB...30..244L. S2CID 118618820. arXiv:1412.6950 . doi:10.3103/S0884591314050055.

[wittenmyer-7] Wittenmyer, Robert A.; Gao, Dongyang; Hu, Shao Ming; Villaver, Eva; Endl, Michael; Wright, Duncan. The Weihai Observatory Search for Close-in Planets Orbiting Giant Stars. Publications of the Astronomical Society of the Pacific. 2015, 127 (956): 1021. Bibcode:2015PASP..127.1021W. S2CID 117305333. arXiv:1507.06051 . doi:10.1086/683258.

[hekker-8] Hekker, S.; Meléndez, J. Precise radial velocities of giant stars. III. Spectroscopic stellar parameters. Astronomy and Astrophysics. 2007, 475 (3): 1003. Bibcode:2007A&A...475.1003H. S2CID 10436552. arXiv:0709.1145 . doi:10.1051/0004-6361:20078233.

[soubiran-9] 9.0 ^9.1 Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants. Astronomy and Astrophysics. 2008, 480 (1): 91–101. Bibcode:2008A&A...480...91S. S2CID 16602121. arXiv:0712.1370 . doi:10.1051/0004-6361:20078788.

[IAU-LSN-10] 10.0 ^10.1 Naming Stars. IAU.org. [2017-12-16]. （原始内容存档于2020-04-11）.

[11] Wagman, Morton. Lost Stars. Blacksburg, Virginia: McDonald and Woodward. 2003. ISBN 0-939923-78-5.

[12] Allen, R. H. Star Names: Their Lore and Meaning Reprint. New York, NY: Dover Publications Inc. 1963: 264. ISBN 0-486-21079-0.

[13] Leo Minor: The little lion （页面存档备份，存于互联网档案馆）- Ian Ridpath's Star Tales

[WGSN-14] IAU Working Group on Star Names (WGSN). [2016-05-22]. （原始内容存档于2019-06-26）.

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

势四

命名法

相關條目

參考資料

Portal di Ensiklopedia Dunia