SAO 20575,即BD+60°2522,是在天球上位于仙后座的一颗明亮O型恒星,周围是由恒星本身恒星风形成的气泡星云(NGC 7635)。该恒星的详细光谱类型仍不明,并且在恒星外观与该恒星对邻近星云造成的影响之间有许多光谱特征和两者之间的不一致,但它无疑是一颗高光度的大质量恒星[6]。对该恒星直接进行光谱观测的结果显示它是O6.5型恒星,表面有效温度37,500K。SAO 20575是银河系英仙臂内距离地球约8500光年的仙后座OB2星协的成员恒星[8][9]

BD+60°2522

SAO 20575与环绕于周围的星云NGC 7635
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)
观测资料
历元 J2000
星座 仙后座
星官
赤经 23h 20m 44.5203s[1]
赤纬 +61° 11′ 40.561″[1]
视星等(V) 8.67[2]
特性
光谱分类O6.5(f)(n)p[3]
U−B 色指数−0.62[2]
B−V 色指数+0.41[2]
天体测定
径向速度 (Rv)−26[4] km/s
自行 (μ) 赤经:3.10[1] mas/yr
赤纬:4.60[1] mas/yr
视差 (π)13.0 ± 8.0[5] mas
距离2,400[6] pc
绝对星等 (MV)−5.5[6]
详细资料 [7]
质量44 M
半径15 R
亮度398,000 L
温度37,500 K
自转速度 (v sin i)178 - 240 km/s
年龄2[8] Myr
其他命名
SAO 20575 IRAS 23185+6055 2MASS J23204452+6111404
参考数据库
SIMBAD资料

虽然SAO 20575的年龄约2百万年,周围的星云年龄只有约4万年。星云的气泡状结构被认为是恒星风超音速状态下撞击星际物质所产生的震波而形成。SAO 20575的恒星风速度高达1,800–2,500 km/s,使其每年损失的质量达到太阳的百万分之一[8]

参考资料

编辑
  1. ^ 1.0 1.1 1.2 1.3 Hog, E.; Kuzmin, A.; Bastian, U.; Fabricius, C.; Kuimov, K.; Lindegren, L.; Makarov, V. V.; Roeser, S. The TYCHO Reference Catalogue. Astronomy and Astrophysics. 1998, 335: L65. Bibcode:1998A&A...335L..65H. 
  2. ^ 2.0 2.1 2.2 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. ^ Walborn, Nolan R.; Howarth, Ian D.; Evans, Christopher J.; Crowther, Paul A.; Moffat, Anthony F. J.; St-Louis, Nicole; Fariña, Cecilia; Bosch, Guillermo L.; Morrell, Nidia I.; Barbá, Rodolfo H.; Van Loon, Jacco Th. The Onfp Class in the Magellanic Clouds. The Astronomical Journal. 2010, 139 (3): 1283. Bibcode:2010AJ....139.1283W. arXiv:1001.4032 . doi:10.1088/0004-6256/139/3/1283. 
  4. ^ Wilson, Ralph Elmer. General Catalogue of Stellar Radial Velocities. Carnegie Institution of Washington. 1953. Bibcode:1953GCRV..C......0W. LCCN 54001336. 
  5. ^ Jenkins, Louise F. General Catalogue of Trigonometric Stellar Parallaxes. Yale University Observatory. 1952. Bibcode:1952gcsr.book.....J. LCCN 53001043. 
  6. ^ 6.0 6.1 6.2 Moore, B. D.; Walter, D. K.; Hester, J. J.; Scowen, P. A.; Dufour, R. J.; Buckalew, B. A. Hubble Space Telescope Observations of the Windblown Nebula NGC 7635. The Astronomical Journal. 2002, 124 (6): 3313. Bibcode:2002AJ....124.3313M. doi:10.1086/344596. 
  7. ^ Rauw, G.; De Becker, M.; Vreux, J. -M. Line profile variability in the spectra of Oef stars. Astronomy and Astrophysics. 2003, 399: 287. Bibcode:2003A&A...399..287R. arXiv:astro-ph/0408253 . doi:10.1051/0004-6361:20021776. 
  8. ^ 8.0 8.1 8.2 Anand, M. Y.; Kagali, B. A.; Murthy, Jayant. Study of Bubble nebula using IUE high resolution spectra. Bulletin of the Astronomical Society of India. 2009, 37: 1. Bibcode:2009BASI...37....1A. arXiv:0903.2828 . 
  9. ^ Mason, Brian D.; Hartkopf, William I.; Gies, Douglas R.; Henry, Todd J.; Helsel, John W. The High Angular Resolution Multiplicity of Massive Stars. The Astronomical Journal. 2009, 137 (2): 3358. Bibcode:2009AJ....137.3358M. arXiv:0811.0492 . doi:10.1088/0004-6256/137/2/3358.