罗斯248

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罗斯248
觀測資料
曆元 J2000
星座 仙女座
星官
赤經 23h 41m 54.99s[1]
赤緯 +44° 10′ 40.8″[1]
視星等(V) 12.29[2]
特性
光谱分类 M6e[3]
U−B 色指数 +1.48[2]
B−V 色指数 +1.92[2]
变星类型 耀星
天体测定
径向速度 (Rv) -81[4] km/s
自行 (μ) 赤经:111[5] mas/yr
赤纬:-1584[5] mas/yr
视差 (π) 316.80 ± 1.10 mas
距离 10.3 ± 0.04 ly
(3.16 ± 0.01 pc)
绝对星等 (MV) 14.79[6]
詳細資料
質量 0.12[7] M
半徑 0.16[8] R
表面重力 (log g) 5.12[3]
亮度 0.0018[9] L
溫度 2,799[3] K
自轉 v sin i < 3 km/s[10]
其他命名
HH Andromedae, HH And, GCTP 5736.00, GJ 905, Gl 171-010, LHS 549, 2MASS J23415498+4410407.[2]

罗斯248仙女座HH)是一颗离地球大约10.3光年(3.26秒差距)的红矮星,位于仙女座内。这颗恒星由弗兰克·埃尔莫尔·罗斯于1926年首先列入他的第二张自行恒星星表[11]

该恒星的质量为太阳质量的16%,而半径为太阳半径的16%,但是光度只有太阳光度的0.2%。尽管它离地球较近,但还是不能用肉眼看到[12]。这是一颗耀星,因此有时光度会增加[13]。因此它很有可能是一颗周期为4.2年的长周期变星。它的视星等在12.23到12.34之间变化[14]。1950年,它成为第一颗由于光球层斑点而导致光度略微变化的恒星[15]

伴星[编辑]

美国斯普劳尔天文台的长期观测说明它没有不可见的伴星对其造成扰动[15]。研究该星的自行表明在较远的距离上(大约100–1400天文单位)可能有棕矮星或伴星绕其运转,但至今还未发现[16]一项研究使用哈勃空间望远镜的宽视野行星相机寻找它的伴星,结果没有任何发现[6],另一项近红外散斑干涉研究也是一无所获[17]。然而,没有一项研究能排除伴星太小而无法观测到的可能性。

距离[编辑]

20000年前至80000年后离地球最近的恒星变化情况

该恒星的空间速度是U = –32.9 ± 0.7 km/s,V = –74.3 ± 1.3 km/s以及W = 0.0 ± 1.4 km/s[18]。罗斯248的运行轨道将使它在未来不断靠近太阳系。1993年,马修斯提出在大约33000年以后罗斯248将成为离太阳最近的恒星,并在36000年后到达离太阳最近的距离3.024光年(0.927秒差距)[19]。然而,从那时开始它会逐渐远去,并将在42000年以后比目前最近的比邻星更远[19]

探测[编辑]

美国国家航空航天局旅行者2号飞船正在大致向罗斯248的方向飞行,预计将在40176年内到达距离它1.76光年(0.54秒差距)的地方[20]。如果有一艘以25.4 km/s的速度脱离太阳系的飞船,那么它将在37000年后恰好在罗斯248离太阳最近时抵达那里。相比而言,旅行者1号的逃逸速度为16.6 km/s[21]

场星[编辑]

名称 赤经 赤纬 视星等 (V) 光谱类型 数据来源
PLX 5735 23h 41m 54s +44h 14m 00s 12.6 A5 Simbad

参见[编辑]

参考资料[编辑]

  1. ^ 1.0 1.1 Cutri, R. M. et al. 2MASS All Sky Catalog of point sources. NASA/IPAC. 2003.June. Bibcode:2003tmc..book.....C. 
  2. ^ 2.0 2.1 2.2 2.3 V* HH And – Flare Star. SIMBADa. Centre de Données astronomiques de Strasbourg. [2009-09-06]. 
  3. ^ 3.0 3.1 3.2 Cenarro, A. J.; Peletier, R. F.; Sánchez–blázquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcón–barroso, J.; Gorgas, J. 等. Medium-resolution Isaac Newton Telescope Library of Empirical Spectra – II. The Stellar Atmospheric Parameters. Monthly Notices of the Royal Astronomical Society. 2007, 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. 
  4. ^ Wilson, Ralph Elmer. General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. 1953. Bibcode:1953QB901.W495..... 
  5. ^ 5.0 5.1 Lépine, Sébastien; Shara, Michael M. A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog). The Astronomical Journal. 2005.March, 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. 
  6. ^ 6.0 6.1 Schroeder, Daniel J.; Golimowski, David A.; Brukardt, Ryan A.; Burrows, Christopher J.; Caldwell, John J.; Fastie, William G.; Ford, Holland C.; Hesman, Brigette et al. A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2. The Astronomical Journal. 2000, 119: 906–922. Bibcode:2000AJ....119..906S. doi:10.1086/301227. 
  7. ^ The One Hundred Nearest Star Systems. Research Consortium on Nearby Stars. 2009-01-01 [2009-09-06]. 
  8. ^ Johnson, H. M.; Wright, C. D. Predicted infrared brightness of stars within 25 parsecs of the Sun. Astrophysical Journal Supplement Series. 1983.November, 53: 643–711. Bibcode:1983ApJS...53..643J. doi:10.1086/190905.  See p. 705.
  9. ^ West, Frederick R. Monitoring Nearby Stars for Transits by Extrasolar Jovial Planets, II: Transits of M-Type (Red) Dwarf Stars by Close Extrasolar Giant (Jovian) Planets. The Journal of the American Association of Variable Star Observers. 1999.June, 27 (1): 77–78. Bibcode:1999JAVSO..27...77W. 
  10. ^ Reiners, A.; Basri, G. The First Direct Measurements of Surface Magnetic Fields on Very Low Mass Stars. The Astrophysical Journal. 2007.February, 656 (2): 1121–1135. arXiv:astro-ph/0610365. Bibcode:2007ApJ...656.1121R. doi:10.1086/510304. 
  11. ^ Ross, Frank E. New proper-motion stars, (second list). Astronomical Journal. 1926.February, 36 (856): 124–128. Bibcode:1926AJ.....36..124R. doi:10.1086/104699. 
  12. ^ Routray, Sudhir K., Light Years Away: The Whole Creation at a Glance, iUniverse. 2004:  31, ISBN 0595335829 
  13. ^ Poveda, Arcadio; Allen, Christine; Herrera, Miguel Angel. Chromospheric Activity, Stellar Winds and Red Stragglers. Workshop on Colliding Winds in Binary Stars to Honor Jorge Sahade, 5. Universidad Nacional Autonoma de Mexico. 1996: pp. 16–20. 
  14. ^ Weis, Edward W. Long term variability in dwarf M stars. Astronomical Journal. 1994.March, 107 (3): 1135–1140. Bibcode:1994AJ....107.1135W. doi:10.1086/116925. 
  15. ^ 15.0 15.1 Lippincott, S. L. Astrometric search for unseen stellar and sub-stellar companions to nearby stars and the possibility of their detection. Space Science Reviews. 1978.July, 22: 153–189. Bibcode:1978SSRv...22..153L. doi:10.1007/BF00212072. 
  16. ^ Hinz, Joannah L. et al. A Near-Infrared, Wide-Field, Proper-Motion Search for Brown Dwarfs. The Astronomical Journal. 2002.February, 123 (4): 2027–2032. arXiv:astro-ph/0201140. Bibcode:2002AJ....123.2027H. doi:10.1086/339555. 
  17. ^ Leinert, C.; Henry, T.; Glindemann, A.; McCarthy, D. W., Jr. A search for companions to nearby southern M dwarfs with near-infrared speckle interferometry. Astronomy and Astrophysics. 1997.September, 325: 159–166. Bibcode:1997A&A...325..159L. 
  18. ^ Leggett, S. K. Infrared colors of low-mass stars. Astrophysical Journal Supplement Series. 1992.September, 82 (1): 351–394. Bibcode:1992ApJS...82..351L. doi:10.1086/191720. 
  19. ^ 19.0 19.1 Matthews, R. A. J. The Close Approach of Stars in the Solar Neighborhood. The Royal Astronomical Society Quarterly Journal. Spring 1994, 35 (1): 1. Bibcode:1994QJRAS..35....1M. 
  20. ^ Littmann, Mark. Planets Beyond: Discovering the Outer Solar System. Courier Dover Publications. 2004. 167. ISBN 0486436020. 
  21. ^ West, F. R., A Suggested Future Space Mission to the Low-Luminosity Star Ross 248=Gliese 905, Bulletin of the American Astronomical Society. March 1985, 17: 552, Bibcode 1985BAAS...17..552W 

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