HD 49798是在船尾座的一顆聯星,距離地球大約650秒差距。它的視星等為 +8.3等。

HD 49798
觀測資料
曆元 J2000
星座 船尾座
星官
赤經 06h 48m 04.69996s[1]
赤緯 −44° 18′ 58.4377″[1]
視星等(V) 8.287[2]
特性
光譜分類sdO6p
U−B 色指數−1.259[2]
B−V 色指數−0.270[2]
變星類型高質量X射線聯星(HMXB)[3]
天體測定
徑向速度 (Rv)12.10[4] km/s
自行 (μ) 赤經:−4.73[1] mas/yr
赤緯:5.39[1] mas/yr
視差 (π)1.20 ± 0.50[1] mas
距離650[3] pc
軌道[3]
繞行週期 (P)1.55天
偏心率 (e)0.0
傾斜角 (i)82°
詳細資料
sdO5.5[5]
質量1.50[3] M
半徑1.45[6] R
表面重力 (log g)4.25[6]
亮度3,943[6] L
溫度47,500[6] K
WD
質量1.28[3] M
其他命名
HD 49798, HR 6978, CD−44°2920, SAO 218207, HIP 32602, AAVSO 0645-44
參考資料庫
SIMBAD資料

HD 49798是在1964年被發現是一顆罕見的,欠缺氫融合的O型次矮星[7]。它被認定是聯星,但是始終未能目視或從光譜檢測出其伴星[8]

在它的附近,科學家發現了X射線源,並標示為RX J0648.0-4418。但是只有XMM-牛頓衛星太空望遠鏡能夠識別發出這個輻射的天體。它是一顆質量約為1.3太陽質量白矮星,在軌道上以13秒的週期環繞着HD 49798[9]。這一系統被認為是超新星的候選者,在數千年後可能爆炸成為Ia型超新星 [10][11]

參考資料

編輯
  1. ^ 1.0 1.1 1.2 1.3 1.4 Van Leeuwen, F. Validation of the new Hipparcos reduction. Astronomy and Astrophysics. 2007, 474 (2): 653. Bibcode:2007A&A...474..653V. arXiv:0708.1752 . doi:10.1051/0004-6361:20078357. 
  2. ^ 2.0 2.1 2.2 Landolt, Arlo U.; Uomoto, Alan K. Optical Multicolor Photometry of Spectrophotometric Standard Stars. The Astronomical Journal. 2007, 133 (3): 768. Bibcode:2007AJ....133..768L. arXiv:0704.3030 . doi:10.1086/510485. 
  3. ^ 3.0 3.1 3.2 3.3 3.4 Mereghetti, S.; La Palombara, N.; Tiengo, A.; Sartore, N.; Esposito, P.; Israel, G. L.; Stella, L. X-ray emission from the luminous O-type subdwarf HD 49798 and its compact companion. Astronomy & Astrophysics. 2013, 553: A46. Bibcode:2013A&A...553A..46M. arXiv:1304.1653 . doi:10.1051/0004-6361/201321271. 
  4. ^ Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S. SB9: The ninth catalogue of spectroscopic binary orbits. Astronomy and Astrophysics. 2004, 424 (2): 727. Bibcode:2004A&A...424..727P. arXiv:astro-ph/0406573 . doi:10.1051/0004-6361:20041213. 
  5. ^ Mereghetti, S.; Tiengo, A.; Esposito, P.; La Palombara, N.; Israel, G. L.; Stella, L. An Ultramassive, Fast-Spinning White Dwarf in a Peculiar Binary System. Science. 2009, 325 (5945): 1222. Bibcode:2009Sci...325.1222M. PMID 19729650. arXiv:1003.0997 . doi:10.1126/science.1176252. 
  6. ^ 6.0 6.1 6.2 6.3 Kudritzki, R. P.; Simon, K. P. Non-LTE analysis of subluminous O-star. The hydrogen-deficient subdwarf O-binary HD 49798. Astronomy and Astrophysics. 1978, 70: 653. Bibcode:1978A&A....70..653K. 
  7. ^ Jaschek, Mercedes; Jaschek, Carlos. HD 49798, a New O-Type Subdwarf. Publications of the Astronomical Society of the Pacific. 1963, 75: 365. Bibcode:1963PASP...75..365J. doi:10.1086/127968. 
  8. ^ Thackeray, A. D. The spectroscopic orbit of the O-type subdwarf HD 49798. Monthly Notices of the Royal Astronomical Society. 1970, 150 (2): 215. Bibcode:1970MNRAS.150..215T. doi:10.1093/mnras/150.2.215. 
  9. ^ Bisscheroux, B. C.; Pols, O. R.; Kahabka, P.; Belloni, T.; Van Den Heuvel, E. P. J. The nature of the bright subdwarf HD 49798 and its X-ray pulsating companion. Astronomy and Astrophysics. 1997, 317: 815. Bibcode:1997A&A...317..815B. 
  10. ^ Wang, Bo; Han, Zhanwen. Progenitors of type Ia supernovae. New Astronomy Reviews. 2012, 56 (4): 122. Bibcode:2012NewAR..56..122W. arXiv:1204.1155 . doi:10.1016/j.newar.2012.04.001. 
  11. ^ Liu, Dong-Dong; Zhou, Wei-Hong; Wu, Cheng-Yuan; Wang, Bo. Is the X-ray pulsating companion of HD 49798 a possible type Ia supernova progenitor?. Research in Astronomy and Astrophysics. 2015, 15 (11): 1813. Bibcode:2015RAA....15.1813L. arXiv:1504.01461 . doi:10.1088/1674-4527/15/11/004.