CRITICAL DIFFERENCES AND CLUES IN ETA CAR'S 2009 EVENT,
CRITICAL DIFFERENCES AND CLUES IN ETA CAR'S 2009 EVENT,
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ETA CAR 2009 年活动中的关键差异和线索，
DOI：
10.1088/0004-637x/740/2/80
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
G. Ferland
中科院分区：
文献类型：
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作者：
A. Mehner;K. Davidson;John C. Martin;R. Humphreys;K. Ishibashi;G. Ferland
我们用哈勃太空望远镜WFPC2和双子座GMOS在2009年的整个光谱事件中监测了船底座埃塔，预计这次光谱事件与2003年的前一次有所不同。在这里，我们报告了观察到的事件之间的主要差异及其含义。其中一些结果是出乎意料的。(1) 2009年紫外光亮度最小值更深。这表明，事件早期阶段的物理条件取决于与“正常”事件间风不同的参数。主星额外的物质抛射是一个可能的原因。(2) He ii λ4687的亮度最大值在数周后又出现了一次。我们解释了为什么这一事实和λ4687极大值的时间强烈支持5-10年前提出的x射线和λ4687行为的“激波破裂”假设。我们通过小矮人星云中尘埃反射的光线，观察到了这颗恒星的极地景象。令人惊讶的是，在那个位置，发射线亮度和多普勒速度的变化与恒星的直接视图非常相似，这对于任何与轨道有关的现象都不应该是正确的。这一结果对所有依赖于副恒星轨道运动的速度解释提出了非常严重的质疑。(4) H i、He i和Fe ii特征的纬度相关变化揭示了事件期间风的各个方面。此外，我们还讨论了观测结果对几个关键的未解决问题的影响。
We monitored Eta Carinae with the Hubble Space Telescope WFPC2 and Gemini GMOS throughout the 2009 spectroscopic event, which was expected to differ from its predecessor in 2003. Here we report major observed differences between events and their implications. Some of these results were quite unexpected. (1) The UV brightness minimum was much deeper in 2009. This suggests that physical conditions in the early stages of an event depend on different parameters than the “normal” inter-event wind. Extra mass ejection from the primary star is one possible cause. (2) The expected He ii λ4687 brightness maximum was followed several weeks later by another. We explain why this fact and the timing of the λ4687 maxima strongly support a “shock breakup” hypothesis for X-ray and λ4687 behavior as proposed 5–10 years ago. (3) We observed a polar view of the star via light reflected by dust in the Homunculus nebula. Surprisingly, at that location, the variations of emission-line brightness and Doppler velocities closely resembled a direct view of the star, which should not have been true for any phenomena related to the orbit. This result casts very serious doubt on all the proposed velocity interpretations that depend on the secondary star's orbital motion. (4) Latitude-dependent variations of H i, He i, and Fe ii features reveal aspects of wind behavior during the event. In addition, we discuss implications of the observations for several crucial unsolved problems.
切伦科夫光下的塔姆问题
DOI：
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发表时间：
2018
期刊：
影响因子：
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作者：
Prutchayawoot Thopan;Rika Oki;Hubert Gnaser;Toshio Seki;Takaaki Aoki;Jiro Matsuo;濱 広幸
通讯作者：
濱 広幸