在五个过渡盘VLT/NACO中排除未分辨的双星：深2.12和1.75 μm窄带成像
Ruling out unresolved binaries in five transitional disks VLT/NACO: deep 2.12 and 1.75 μm narrow-band imaging
摘要：
目标。我们的目标是检测内孔/间隙区域的五个众所周知的过渡盘的样品内的同伴的存在下，使用空间分辨成像在近红外与VLT/NACO/S13相机，探测投影距离通常为0.1至7弧秒的主要。样本包括恒星DoAr 21、HD 135344 B（SAO 206462）、HR 4796 A、T Cha和TW Hya，年龄小于100万年到1000万年，光谱类型为A0到K7，洞/隙外半径为4到100 AU。方法.为了提高对比度和避免在点扩散函数（PSF）的核心处饱和，我们使用1.75和2.12 μm的窄带滤波器。“局部优化的图像组合”（LOCI）算法被应用于最佳的斑点噪声去除和PSF减法，提供了0.5-1.5 mag的对比度比经典的方法增加。结果但我们可能会因为不利的投影而错过伴星，VLT/NACO的观测排除了所有五个过渡盘中未分辨伴星的存在，这些伴星的内径从主星到0”.1，探测极限为2到5等。在磁盘的外部区域的检测极限通常达到8至9 MAG的对比度和4.7 MAG的T茶。因此，NACO图像解决了所有磁盘的内孔/间隙区域的一部分，除了TW Hya，其内孔仅为4 AU。5σ灵敏度分布，加上一个选定的演化模型，允许丢弃T Cha内孔/间隙区域的恒星同伴，并下降到HD 135344 B和HR 4796 A的亚恒星区域。DoAr 21是五个圆盘样本中唯一一个NACO图像灵敏度足以检测质量小于\sim 13 MJup的天体，即半径大于\sim 76 AU（0”.63）的潜在巨行星或低质量棕矮星。
英文摘要：
Aims. We aim at detecting the presence of companions inside the inner hole/gap region of a sample of five well known transitional disks using spatially-resolved imaging in the near-IR with the VLT/NACO/S13 camera, which probes projected distances from the primary of typically 0.1 to 7 arcsec. The sample includes the stars DoAr 21, HD 135344B (SAO 206462), HR 4796A, T Cha, and TW Hya, spanning ages of less than 1 to 10 Myr, spectral types of A0 to K7, and hole/gap outer radii of 4 to 100 AU. Methods. In order to enhance the contrast and to avoid saturation at the core of the point-spread function (PSF), we use narrow-band filters at 1.75 and 2.12 μm. The "locally optimized combination of images" (LOCI) algorithm is applied for an optimal speckle noise removal and PSF subtraction, providing an increase of 0.5-1.5 mag in contrast over the classic method. Results. With the proviso that we could have missed companions owing to unfavorable projections, the VLT/NACO observations rule out the presence of unresolved companions down to an inner radius of about 0".1 from the primary in all five transitional disks and with a detection limit of 2 to 5 mag in contrast. In the disk outer regions the detection limits typically reach 8 to 9 mag in contrast and 4.7 mag for T Cha. Hence, the NACO images resolve part of the inner hole/gap region of all disks with the exception of TW Hya, for which the inner hole is only 4 AU. The 5σ sensitivity profiles, together with a selected evolutionary model, allow to discard stellar companions within the inner hole/gap region of T Cha, and down to the substellar regime for HD 135344B and HR 4796A. DoAr 21 is the only object from the sample of five disks for which the NACO images are sensitive enough for a detection of objects less massive than \sim 13 MJup that is, potential giant planets or low-mass brown dwarfs at radii larger than \sim 76 AU (0".63).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
