Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris
Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris
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红巨星 R Sculptoris 的热脉冲周期中意外的大量质量损失
DOI：
10.1038/nature11511
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发表时间：
2012
期刊：
影响因子：
64.8
通讯作者：
de Gregorio-Monsalvo
中科院分区：
文献类型：
--
作者：
Maercker;Mohamed;Vlemmings;Ramstedt;Groenewegen;Humphreys;Kerschbaum;Lindqvist;Olofsson;Paladini;Wittkowski;de Gregorio-Monsalvo
渐近巨星分支恒星 R Sculptoris 被一层分离的尘埃和气体外壳包围。壳层起源于热脉冲，在此期间恒星经历了短暂的质量损失增加。迄今为止，不可能通过观测来限制热脉冲期间和之后的时间尺度和质量损失特性，这些参数决定了渐近巨星分支的寿命和恒星返回的元素数量。在这里，我们报告了对 R Sculptoris 周围星周包层和外壳的 CO 排放观测，角分辨率为 1.3 英寸。此前人们认为只是一个具有块状结构的薄球壳，但后来发现它还包含螺旋结构。先前已经观察到与星周包层相关的螺旋结构，从而得出该系统必须是双星系统的结论，,,。将观测数据与流体动力学模拟相结合，我们得出结论，R Sculptoris 是一个双星系统，大约在 1,800 年前经历过一次热脉冲，持续了大约 200 年。大约 3 × 10−3 个太阳质量的物质以 14.3 km s−1 的速度喷射出来，其速率比脉冲前质量损失率高出约 30 倍。这表明，在脉冲期间和脉冲之后返回星际介质的质量大约是之前认为的三倍。
The asymptotic-giant-branch star R Sculptoris is surrounded by a detached shell of dust and gas,. The shell originates from a thermal pulse during which the star underwent a brief period of increased mass loss,. It has hitherto been impossible to constrain observationally the timescales and mass-loss properties during and after a thermal pulse—parameters that determine the lifetime of the asymptotic giant branch and the amount of elements returned by the star. Here we report observations of CO emission from the circumstellar envelope and shell around R Sculptoris with an angular resolution of 1.3″. What was previously thought to be only a thin, spherical shell with a clumpy structure is revealed to also contain a spiral structure. Spiral structures associated with circumstellar envelopes have been previously seen, leading to the conclusion that the systems must be binaries,,,. Combining the observational data with hydrodynamic simulations, we conclude that R Sculptoris is a binary system that underwent a thermal pulse about 1,800 years ago, lasting approximately 200 years. About 3 × 10−3solar masses of material were ejected at a velocity of 14.3 km s−1and at a rate around 30 times higher than the pre-pulse mass-loss rate. This shows that about three times more mass was returned to the interstellar medium during and immediately after the pulse than previously thought.
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影响因子：
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