羅斯248仙女座HH)是一顆離地球大約10.3光年(3.26秒差距)的紅矮星,位於仙女座內。這顆恆星由弗蘭克·埃爾莫爾·羅斯於1926年首先列入他的第二張自行恆星星表[11]

羅斯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
光譜分類M6e[3]
U−B 色指數+1.48[2]
B−V 色指數+1.92[2]
變星類型耀星
天體測定
徑向速度 (Rv)-81[4] km/s
自行 (μ) 赤經:111[5] mas/yr
赤緯:-1584[5] mas/yr
視差 (π)316.80 ± 1.10 mas
距離10.30 ± 0.04 ly
(3.16 ± 0.01 pc)
絕對星等 (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]

該恆星的質量為太陽質量的16%,而半徑為太陽半徑的16%,但是光度只有太陽光度的0.2%。儘管它離地球較近,但還是不能用肉眼看到[12]。這是一顆耀星,因此有時光度會增加[13]。因此它很有可能是一顆週期為4.2年的長週期變星。它的視星等在12.23到12.34之間變化[14]。1950年,它成為第一顆由於光球層斑點而導致光度略微變化的恆星[15]

伴星

美國斯普勞爾天文台的長期觀測說明它沒有不可見的伴星對其造成擾動[15]。研究該星的自行表明在較遠的距離上(大約100–1400天文單位)可能有棕矮星或伴星繞其運轉,但至今還未發現[16]一項研究使用哈勃太空望遠鏡的寬視野行星相機尋找它的伴星,結果沒有任何發現[6],另一項近紅外散斑干涉研究也是一無所獲[17]。然而,沒有一項研究能排除伴星太小而無法觀測到的可能性。

距離

 
20000年前至80000年後離地球最近的恆星變化情況

該恆星的空間速度是U = –32.9 ± 0.7 km/s,V = –74.3 ± 1.3 km/s以及W = 0.0 ± 1.4 km/s[18]。羅斯248的運行軌道將使它在未來不斷靠近太陽系。1993年,馬修斯提出在大約33000年以後羅斯248將成為離太陽最近的恆星,並在36000年後到達離太陽最近的距離3.024光年(0.927秒差距)[19]。然而,從那時開始它會逐漸遠去,並將在42000年以後比目前最近的比鄰星更遠[19]

探測

美國太空總署航行者2號飛船正在大致向羅斯248的方向飛行,預計將在40176年內到達距離它1.76光年(0.54秒差距)的地方[20]。如果現在有一艘太空船以25.4 km/s的速度脫離太陽系,那麼它將在37000年後恰好在羅斯248離太陽最近時抵達那裏。相比而言,航行者1號的逃逸速度為16.6 km/s[21]

場星

名稱 赤經 赤緯 視星等 (V) 光譜類型 數據來源
PLX 5735 23h 41m 54s +44h 14m 00s 12.6 A5 Simbad頁面存檔備份,存於互聯網檔案館

參見

參考資料

  1. ^ 1.0 1.1 Cutri, R. M.; et al. 2MASS All Sky Catalog of point sources. NASA/IPAC. June 2003. 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]. (原始內容存檔於2019-06-03). 
  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.; Jiménez-Vicente, J. 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. Bibcode:2007MNRAS.374..664C. arXiv:astro-ph/0611618 . 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. March 2005, 129 (3): 1483–1522. Bibcode:2005AJ....129.1483L. arXiv:astro-ph/0412070 . 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; Kletskin, Ilona. 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]. (原始內容存檔於2012-05-14). 
  8. ^ Johnson, H. M.; Wright, C. D. Predicted infrared brightness of stars within 25 parsecs of the Sun. Astrophysical Journal Supplement Series. November 1983, 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. June 1999, 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. February 2007, 656 (2): 1121–1135. Bibcode:2007ApJ...656.1121R. arXiv:astro-ph/0610365 . doi:10.1086/510304. 
  11. ^ Ross, Frank E. New proper-motion stars, (second list). Astronomical Journal. February 1926, 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: 31, 2004 [2012-01-13], ISBN 0595335829, (原始內容存檔於2013-06-20) 
  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: 16–20. 1996. 
  14. ^ Weis, Edward W. Long term variability in dwarf M stars. Astronomical Journal. March 1994, 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. July 1978, 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. February 2002, 123 (4): 2027–2032. Bibcode:2002AJ....123.2027H. arXiv:astro-ph/0201140 . 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. September 1997, 325: 159–166. Bibcode:1997A&A...325..159L. 
  18. ^ Leggett, S. K. Infrared colors of low-mass stars. Astrophysical Journal Supplement Series. September 1992, 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 

外部連結