High-contrast imaging of Sirius A with VLT/SPHERE: looking for giant planets down to one astronomical unit
High-contrast imaging of Sirius A with VLT/SPHERE: looking for giant planets down to one astronomical unit
复制标题
使用 VLT/SPHERE 对天狼星 A 进行高对比度成像：寻找小至一个天文单位的巨行星
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
F. Allard
中科院分区：
文献类型：
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作者：
A. Vigan;A. Vigan;C. Gry;G. Salter;D. Mesa;D. Homeier;D. Homeier;C. Moutou;C. Moutou;F. Allard
天狼星一直吸引着大量的科学兴趣，特别是在世纪末发现了一颗伴白色矮星之后。很早以前，人们就提出了第三体的存在来解释系统的一些观测性质。我们提出了新的日冕观测获得的VLT/SPHERE（甚大望远镜/光谱偏振高对比度系外行星研究），探索，第一次，系统的最里面的区域下降到0.2弧秒（0.5 Au）从天狼星A。我们的观测覆盖了从0.95到2.3 μ m的近红外波段，它们提供了在这些角间距上达到的最佳天空对比度。在详细介绍了我们的SPHERE/IRDIFS数据分析的步骤后，我们提出了一个强大的方法来推导高对比度成像仪和光谱仪的多光谱数据的检测限。在原始性能方面，我们报告的对比度为14.3 mag，0.2 arcsec，类似于16.3 mag，0.4-1.0 arcsec范围内，并下降到19 mag，3.7 arcsec。在物理单位上，我们的观测对0.5 Au的11 M-Jup，1-2 Au范围内的6-7 M-Jup以及10 Au的4 M-Jup的巨行星敏感。尽管我们的观测异常敏感，但我们没有报告在天狼星A周围发现其他伴星。使用蒙特卡罗轨道分析，我们表明，我们可以拒绝，约50%的概率，存在一个8 M-Jup行星轨道在1 Au。
Sirius has always attracted a lot of scientific interest, especially after the discovery of a companion white dwarf at the end of the 19th century. Very early on, the existence of a potential third bodywas put forward to explain some of the observed properties of the system. We present new coronagraphic observations obtained with VLT/SPHERE (Very Large Telescope/SpectroPolarimetric High-contrast Exoplanet REsearch) that explore, for the very first time, the innermost regions of the system down to 0.2 arcsec(0.5 au) from Sirius A. Our observations cover the near-infrared from 0.95 to 2.3 mu m and they offer the best on-sky contrast ever reached at these angular separations. After detailing the steps of our SPHERE/IRDIFS data analysis, we present a robust method to derive detection limits for multispectral data from high-contrast imagers and spectrographs. In terms of raw performance, we report contrasts of 14.3 mag at 0.2 arcsec, similar to 16.3 mag in the 0.4-1.0 arcsec range and down to 19 mag at 3.7 arcsec. In physical units, our observations are sensitive to giant planets down to 11 M-Jup at 0.5 au, 6-7 M-Jup in the 1-2 au range and similar to 4 M-Jup at 10 au. Despite the exceptional sensitivity of our observations, we do not report the detection of additional companions around Sirius A. Using a Monte Carlo orbital analysis, we show that we can reject, with about 50 per cent probability, the existence of an 8 M-Jup planet orbiting at 1 au.
影响因子：
6.5
作者：
Baraffe, Isabelle;Homeier, Derek;Chabrier, Gilles
通讯作者：
Chabrier, Gilles