年轻太阳类比星 DS Tucanae A 的频繁 X 级远紫外耀发
Frequent X-class Far UV Flares from a Young Solar Analog DS Tucanae A
- Pennsylvania State University（宾夕法尼亚州立大学）
- University of Colorado Boulder（科罗拉多大学博尔德分校）
- NASA Goddard Space Flight Center（美国宇航局戈达德太空飞行中心）
- American University（美国大学）
- Lehigh University（利哈伊大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究分析年轻太阳类比星DS Tuc A的远紫外观测，发现26次耀发，能量达10^29-10^31尔格，为早期地球环境和系外行星受耀发影响提供约束。
AI中文摘要：
年轻的太阳类比星 DS Tuc A（约4500万年，光谱型G6V）是地球演化早期阶段太阳的极佳替身。年轻太阳增强的磁活动，以X射线和极紫外辐射、恒星风及耀发的形式，可能影响了早期金星、地球和火星的磁层及大气环境。对DS Tuc A的研究有助于约束早期金星、地球和火星磁层及大气环境的演化，并为研究耀发对凌星系外行星DS Tuc Ab的影响创造了机会。我们分析了哈勃太空望远镜宇宙起源光谱仪在2023年末至2024年初期间获取的约11小时的远紫外（FUV；1130-1450埃）观测数据。我们发现DS Tuc A在约11.1小时的观测中，在过渡区谱线Si IV（1394埃+1402埃）上表现出26次耀发，持续时间范围为90-960秒，在观测波段内FUV绝对能量范围约为10^29-10^31尔格。Si IV耀发伴随着其他色球和过渡区谱线的增强，然而最强的Si IV耀发未显示出由Fe XXI 1354埃示踪的日冕发射增强。我们对每次探测到的耀发进行了分析，包括从FUV耀发能量标定的X射线和热光度、最强耀发的电子密度测量，以及远紫外连续谱对耀发的响应。这些结果为与X100级太阳耀发相当的耀发频率和能量以及年轻太阳类比星中的FUV发射区域提供了约束。
英文摘要：
The young solar analog DS Tuc A (~45 million years old, spectral type G6V) serves as an excellent proxy to the Sun during early stages of the Earth's evolution. The young Sun's enhanced magnetic activity in the form of X-ray and extreme UV emission, stellar wind, and flares likely affected the magnetospheric and atmospheric environments of early Venus, Earth and Mars. Studies of DS Tuc A help constrain evolution of magnetospheric and atmospheric environments of early Venus, Earth, and Mars and create opportunities to study the impact of flares on the transiting exoplanet, DS Tuc Ab. We analyze ~11 hours of Far-ultraviolet (FUV; 1130 - 1450 $\mathring{A}$) observations taken by the Hubble Space Telescope Cosmic Origins Spectrograph during late 2023 and early 2024. We find DS Tuc A exhibited 26 flares over ~11.1 hours of observations in the transition region lines Si IV (1394 $\mathring{A}$ + 1402 $\mathring{A}$), with durations ranging 90 - 960 seconds and FUV absolute energies ranging ~ 10$^{29}$ - 10$^{31}$ erg over the observed bandpass. Si IV flares are accompanied by increases of other chromospheric and transition region lines, however the strongest Si IV flares show no enhanced coronal emission traced by Fe XXI 1354 $\mathring{A}$. We present an analysis of each detected flare, including X-ray and bolometric luminosities scaled from FUV flare energies, electron density measurements for the strongest flares, and the Far-UV continuum response to flaring. These results provide constraints on the frequency and energetics of flares comparable to X100-class solar flares and FUV-emitting regions in young solar analogs.
