轩辕四(α Lyn,α Lyncis)是在北天星座天猫座的一颗视星等+3.13的亮星[4]。不寻常的是,它是天猫座中唯一有拜耳名字的恒星[6]。基于视差的观测,它与地球的距离大约是203光年(62秒差距[1]

轩辕四(天猫座α)
轩辕四的位置(红圈)
观测资料
历元 J2000
星座 天猫座
星官 轩辕星宿
赤经 09h 21m 03.30074s[1]
赤纬 +34° 23′ 33.2245″[1]
视星等(V) +3.14[2]
特性
光谱分类K7 III[3]
U−B 色指数+1.95[4]
B−V 色指数+1.55[4]
天体测定
径向速度 (Rv)37.15[5] km/s
自行 (μ) 赤经:–223.63[1] mas/yr
赤纬:15.18[1] mas/yr
视差 (π)16.06 ± 0.17[1] mas
距离203 ± 2 ly
(62.3 ± 0.7 pc)
详细资料
质量~2[6] M
半径54.50 ± 3.02[7] R
表面重力 (log g)1.5[5]
亮度673 ± 83[7] L
温度3,882[5] K
金属量 [Fe/H]–0.26[5] dex
自转速度 (v sin i)6.4[5] km/s
年龄1.4[6] Gyr
其他命名
天猫座40HR 3705、 HD 80493、BD+35 1979、HIP 45860、 SAO 61414、FK5 352、NSV 4456、GC 12880。[8]
参考数据库
SIMBAD资料

这是一颗巨星,它耗尽了核心的氢,在演化上已经离开主序带。它已经膨胀到太阳半径的55倍,发射的光大约是太阳光度的673倍[7]。估计该恒星外层的有效温度为3882K[5],低于太阳5778K的有效温度,使轩辕四呈现橙色的色调,这是K型恒星的特征[9]

轩辕四疑似是颗小振幅的红色变星[10],它的视星等能从+3.17提升至+3.12[11]。这种变化模式通常发生在已经形成惰性碳核并被氦-融合壳层包围的恒星中,并表明轩辕四正开始演化为米拉型变星[6]

参考资料

  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. 
  2. ^ Ducati, J. R. VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system. CDS/ADC Collection of Electronic Catalogues. 2002, 2237. Bibcode:2002yCat.2237....0D. 
  3. ^ Morgan, W. W.; Keenan, P. C. Spectral Classification. Annual Review of Astronomy and Astrophysics. 1973, 11: 29–50. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333. 
  4. ^ 4.0 4.1 4.2 Johnson, H. L.; et al. UBVRIJKL photometry of the bright stars. Communications of the Lunar and Planetary Laboratory. 1966, 4 (1): 99. Bibcode:1966CoLPL...4...99J. 
  5. ^ 5.0 5.1 5.2 5.3 5.4 5.5 Massarotti, A.; et al. Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity. The Astronomical Journal. 2008, 135 (1): 209–231. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209 . 
  6. ^ 6.0 6.1 6.2 6.3 Kaler, J. B. ALPHA LYN (Alpha Lyncis) and ALSCIAUKAT (31 Lyncis). Stars. University of Illinois. 2005-05-11 [2011-12-26]. (原始内容存档于2016-10-18). 
  7. ^ 7.0 7.1 7.2 Piau, L.; et al. Surface convection and red giants radii measurements. Astronomy and Astrophysics. 2010, 526: 100. Bibcode:2011A&A...526A.100P. S2CID 118533297. arXiv:1010.3649 . doi:10.1051/0004-6361/201014442.  For Mbol, see Table 1.
  8. ^ Alpha Lyncis. SIMBAD. 斯特拉斯堡天文资料中心. [2011-12-12]. 
  9. ^ The Colour of Stars. Australia Telescope Outreach and Education. Commonwealth Scientific and Industrial Research Organisation. 2004-12-21 [2012-01-16]. (原始内容存档于2012-03-18). 
  10. ^ Percy, J. R.; et al. Photometric surveys of suspected small-amplitude red variables. III: An AAVSO photometric photometry survey. Publications of the Astronomical Society of the Pacific. 1994, 106 (700): 611–615. Bibcode:1994PASP..106..611P. doi:10.1086/133420 . 
  11. ^ Kukarkin, B. V.; et al. Catalogue of suspected variable stars. Nachrichtenblatt der Vereinigung der Sternfreunde E.V. 1981. Bibcode:1981NVS...C......0K.