The nearby evolved stars survey – I. JCMT/SCUBA-2 submillimetre detection of the detached shell of U Antliae
The nearby evolved stars survey – I. JCMT/SCUBA-2 submillimetre detection of the detached shell of U Antliae
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DOI：
10.1093/mnras/stz2334
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发表时间：
2019-08
影响因子：
4.8
通讯作者：
T. Dharmawardena;F. Kemper;S. Srinivasan;P. Scicluna;J. Marshall;J. Wouterloot;J. Greaves;S. Goldm
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作者：
T. Dharmawardena;F. Kemper;S. Srinivasan;P. Scicluna;J. Marshall;J. Wouterloot;J. Greaves;S. Goldm
我们提出了最高分辨率的单碟亚毫米观测的分离壳源U Antliae的日期。这些观测是在詹姆斯·克拉克麦克斯韦望远镜上的SCUBA-2仪器上以450美元和850美元的价格获得的，作为邻近演化恒星巡天的一部分。在$850\，{\mu}{\rm m}$处的发射峰值在40弧秒处，并暗示第二个峰值出现在1020弧秒处。在3σ水平上，辐射可以追溯到56弧秒的半径。在850 μ m处观察到的外峰与在Herschel/PACS波长处观察到的峰很好地对齐。通过对星周包层的光谱能量分布拟合和多壳层模型的辐射传输计算，探讨了星周包层中不同的壳层结构和颗粒尺寸沿着的变化。我们确定了壳尘的总质量为（2.0 ± 0.3）× 10−5 M，并确定了产生分离壳的热脉冲发生在3500 ± 500年前。
We present the highest resolution single-dish submillimetre observations of the detached shell source U Antliae to date. The observations were obtained at $450$ and $850\,{\mu}{\rm m}$ with SCUBA-2 instrument on the James Clerk Maxwell Telescope as part of the Nearby Evolved Stars Survey. The emission at $850\,{\mu}{\rm m}$ peaks at 40 arcsec with hints of a second peak seen at ∼20 arcsec. The emission can be traced out to a radius of 56 arcsec at a 3σ level. The outer peak observed at $850\,{\mu}{\rm m}$ aligns well with the peak observed at Herschel/PACS wavelengths. With the help of spectral energy distribution fitting and radiative transfer calculations of multiple-shell models for the circumstellar envelope, we explore the various shell structures and the variation of grain sizes along the in the circumstellar envelope. We determine a total shell dust mass of (2.0 ± 0.3) × 10−5 M⊙ and established that the thermal pulse that gave rise to the detached shell occurred 3500 ± 500 yr ago.