摘要
本文利用蒙特卡罗光谱合成方法，对１９９３年由哈勃空间望远镜和里克天文台同时得到的超新星１９９３Ｊ的紫外及光学波段的光谱，进行研究并将拟合的结果与别人的模型进行了比较。假设太阳丰度及幂律为２０左右的大气密度结构，模型可以与观测较好地符合。通过计算得到光球速度为９５００ｋｍｓ－１左右，光谱的黑体温度为７９９０Ｋ。对于强线如Ｈα及ＨｅＩλ５８７６的特殊谱线轮廓，我们发现大气结构需要是双幂律的，即光球外陡降的内层大气外面，密度变化相当平缓。内外大气的幂律近似为２０和３，交界点在１３０００ｋｍｓ－１左右。外层平缓的大气同时起到了使远紫外光谱变得像观测到的那样平滑的作用。
We present the modeling of the ultraviolet and optical spectra obtained simultaneously on 1993 April 15 with the HST and at Lick Observatory.A Monte Carlo code is employed in the modeling and a comparison is made between models reported by different groups.With an atmosphere similar to the Sun in chemical composition, the observed spectral lines are well reproduced by a power law density structure of index around 20 except the strong Hα and HeIλ5876 lines which have peculiar absorption profiles. The photospheric velocity is found to be 9500km/s and the blackbody temperature of the spectrum is 7990K. For Hα and HeI λ5876, we suggest a two-component density structure which has a smoother layer located immediately outside the steeply decreasing inner envelope. The power law indices are most probably 20 and 3, respectively, with the transition point at about 13000km/s.In addition, this outer smooth layer serves to flatten the far UV spectrum as observed.
基金
国家教委博士生培养基金
