Contrast limits with the Simultaneous Differential Extrasolar Planet Imager (SDI) at the VLT and MMT
Contrast limits with the Simultaneous Differential Extrasolar Planet Imager (SDI) at the VLT and MMT
复制标题
VLT 和 MMT 同步差分太阳系外行星成像仪 (SDI) 的对比度限制
DOI：
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发表时间：
2006
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影响因子：
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通讯作者：
M. Kasper
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文献类型：
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作者：
B. Biller;L. Close;E. Masciadri;R. Lenzen;W. Brandner;D. Mccarthy;T. Henning;E. Nielsen;M. Hartung;S. Kellner;K. Geissler;M. Kasper
我们讨论的对比度限制期间获得的调查年轻（<3亿年），关闭（<50 pc）的恒星与同时差分太阳系外行星成像仪（SDI）在VLT和MMT实施。SDI使用一个双沃拉斯顿棱镜和一个四滤光片，在冷棕矮星和气体巨星光谱中发现的1.62 μm甲烷带头周围的3个波长同时拍摄图像。通过在这些滤波器中执行图像的差异，来自原色的斑点噪声可以被显著衰减，从而导致光子噪声受限的数据。在我们的调查数据中，我们在距离主星0.5英寸的距离处实现了H波段对比度>25000（5σ ΔF1（1.575μm）>10等，对于T6光谱类型，ΔH>10.6等）。主星星。有了这种程度的衰减，我们就可以在10 pc下成像（5σ检测）一颗质量为2-4木星的行星，它位于5 Au，围绕一颗3千万年前的星星。我们目前正在完成对年轻恒星的调查。我们已经获得了完整的数据集，40颗恒星在南天（VLT）和11颗恒星在北方的天空（MMT）。我们相信，我们的SDI图像是有史以来从地面或太空为富含甲烷的同伴拍摄的对比度最高的天文图像。
We discuss contrast limits obtained during a survey of young (<300 Myr), close (<50 pc) stars with the Simultaneous Differential Extrasolar Planet Imager (SDI) implemented at the VLT and the MMT. SDI uses a double Wollaston prism and a quad filter to take images simultaneously at 3 wavelengths surrounding the 1.62 μm methane bandhead found in the spectrum of cool brown dwarfs and gas giants. By performing a difference of images in these filters, speckle noise from the primary can be significantly attenuated, resulting in photon noise limited data. In our survey data, we achieved H band contrasts >25000 (5σ ΔF1(1.575μm)>10 mag, ΔH>10.6 mag for a T6 spectral type) at a separation of 0.5" from the primary star. With this degree of attenuation, we can image (5σ detection) a 2-4 Jupiter mass planet at 5 AU around a 30 Myr star at 10 pc. We are currently completing our survey of young, nearby stars. We have obtained complete datasets for 40 stars in the southern sky (VLT) and 11 stars in the northern sky (MMT). We believe that our SDI images are the highest contrast astronomical images ever made from ground or space for methane rich companions.