典型文献
Spectral Behavior and Flaring Activity of Ⅱ Peg in the Ultraviolet
文献摘要：
We have studied the spectral behavior of the Ⅱ Peg binary system in the ultraviolet band by using International Ultraviolet Explorer (IUE) observations over the period 1979–1993. The ultraviolet observations reveal indication of flare activity in both chromosphere and transition region with their enhanced emission lines. Before and after the flare activity the ultraviolet emission lines show low, intermediate and high flux. The spectral behavior is compared with previous studies. We detect prominent flare activity in 1989, 1990 and 1992. Before and after this period there is a gradual clear decrease in the level of activity. The reddening of Ⅱ Peg was determined from a 2200 ? absorption feature to be E(B?V )=0.10 ± 0.02. We ascertained the average mass loss rate to be≈1 × 10?8 Me yr?1, and an average ultraviolet luminosity to be≈6 × 1029 erg s?1. We attributed the spectral variations to a cyclic behavior of the underlying magnetic dynamo and the prominent activity can be interpreted by the model of a two-ribbon flare.
文献关键词：
中图分类号：
作者姓名：
M.R.Sanad
作者机构：
Astronomy Department,National Research Institute of Astronomy and Geophysics,Helwan,Cairo,Egypt
文献出处：
引用格式：
[1]M.R.Sanad-.Spectral Behavior and Flaring Activity of Ⅱ Peg in the Ultraviolet)[J].天文和天体物理学研究,2022(08):191-197
A类：
Flaring,chromosphere,reddening
B类：
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AB值：
0.556411
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