小熊座π1[14]是在拱极星座小熊座北部的共同自行联星[15]。该对的视星等分别为+6.58和+7.31,综合星等为+6.1[2]。它们位于距离太阳约71光年的地方。两星的角距离为31.4弧秒[15],其对应于实际约680AU[16],并以大约13,100年的周期互绕着彼此运行[9]

小熊座π1
观测数据
历元 J2000.0      分点 J2000.0 (ICRS)
星座 小熊座
小熊座 π1 A
赤经 15h 29m 11.18599s[1]
赤纬 +80° 26′ 54.9713″[1]
视星等 (V) +6.58[2]
小熊座π1 B
赤经 15h 29m 23.59426s[1]
赤纬 +80° 27′ 00.9675″[1]
视星等 (V) +7.31[2]
特性
光谱分类G1.5 V(n)[3] + G9 V[4]
U−B 色指数+0.13[2] + +0.37[2]
B−V 色指数+0.67[2] + +0.79[2]
天体测定
小熊座π1 A
径向速度 (Rv)−16.27±0.09[5] km/s
自行 (μ) 赤经:−225.109[6] mas/yr
赤纬:+107.575[6] mas/yr
视差 (π)45.8577 ± 0.0328[6] mas
距离71.12 ± 0.05 ly
(21.81 ± 0.02 pc)
绝对星等 (MV)4.94±0.04[7]
π1 UMi B
径向速度 (Rv)−15.40±0.70[5] km/s
自行 (μ) 赤经:−217.817[8] mas/yr
赤纬:+105.947[8] mas/yr
视差 (π)45.8038 ± 0.0352[8] mas
距离71.21 ± 0.05 ly
(21.83 ± 0.02 pc)
详细资料
小熊座π1 A
质量1.02[9] M
半径0.98[6] R
表面重力 (log g)4.40[10]
亮度0.929[6] L
温度5,771[10] K
金属量 [Fe/H]−0.22[11] dex
年龄9.22±3.84[12] Gyr
π1 UMi B
质量0.92[9] M
半径0.84[8] R
表面重力 (log g)4.50[10]
亮度0.520[8] L
温度5,408[10] K
其他命名
π1 UMi、​ADS 9696、​WDS J15292+8027[13]
参考数据库
SIMBADπ1 UMi AB
π1 UMi A
π1 UMi B

这两颗恒星都是类太阳恒星,并已被列为天琴-武仙星协的可能成员,该星协是距离太阳最近的移动星群之一[16],然而现在认为这不太可能[17]。 主星小熊座π1 A,质量比太阳高2%,表面有效温度5,771 K,半径为太阳的的98%和辐射热光度太阳的93%。伴星,小熊座π1 B,质量是太阳的92%,温度略低为5,408 K,半径是太阳的 84%,光度略高于太阳的一半。

参考资料

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  8. ^ 8.0 8.1 8.2 8.3 8.4 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
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  10. ^ 10.0 10.1 10.2 10.3 Mishenina, T. V.; et al, Abundances of neutron-capture elements in stars of the Galactic disk substructures, Astronomy & Astrophysics, April 2013, 552: 12, Bibcode:2013A&A...552A.128M, S2CID 119268097, arXiv:1303.1730 , doi:10.1051/0004-6361/201220687, A128. 
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外部链接

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