High-contrast optical imaging of companions: the case of the brown dwarf binary HD 130948BC
High-contrast optical imaging of companions: the case of the brown dwarf binary HD 130948BC
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伴星的高对比度光学成像：以褐矮星双星 HD 130948BC 为例
DOI：
10.1051/0004-6361/201014358
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发表时间：
2010
影响因子：
6.5
通讯作者：
L. F. Rodríguez
中科院分区：
文献类型：
--
作者：
L. Labadie;R. Rebolo;I. Villó;J. A. Pérez;A. Pérez;S. Hildebrandt;B. Femenía;A. Díaz;V. Béjar;A. Oscoz;R. Lopez;J. Piqueras;L. F. Rodríguez
上下文。光学波长下的高对比度成像受到传统近红外优化AO系统适度校正的限制。我们利用新的快速和低读数噪声探测器来探索快速成像与后处理技术相结合的潜力，以探测小角距离下恒星的微弱伴星。目标。我们专注于先前探测到的褐矮星双星HD 130948 BC的i波段直接成像，试图在空间上解析L2+L2系统，该系统被认为是确定次恒星物体动力质量的基准。方法。我们使用2.5 m北欧望远镜上的幸运成像仪器FastCam获得了HD 130948的准衍射限制图像，分辨率为~ 0.1°。为了提高在明亮（I = 5.19±0.03）太阳型恒星附近微弱双星的可探测性，我们对图像进行了基于小波变换滤波的后处理技术，该技术使我们能够在主晕通常占主导地位的区域强烈增强点状源的存在。结果。我们首次在I波段探测到双星棕矮星HD 130948 BC，其信噪比为2.561°±0.007°（46.5 AU），来自HD 130948 a，并在两个独立的数据集（2008年5月29日和7月25日）中确认该物体是真实的，而不是随时间变化的残余斑点。我们不能分辨双星，这可以用我们观测后的天体测量结果来解释，这些结果预测了低于望远镜分辨率的分离。在这个距离上，我们得到了ΔI = 11.30±0.11的对比度，并估计出这颗双星的总星等I = 16.49±0.11，I - J色为3.29±0.13。在1°时，经过图像后处理，我们达到了比主图像微弱10.5等的可探测性。结论。对基于小波变换后处理的散斑成像技术进行了天空验证，提高了散斑成像的高对比度能力。测量到的BD伴星的I−J颜色略蓝，但仍然与L2矮星的典型颜色一致（~ 3.4-3.6）。
Context. High-contrast imaging at optical wavelengths is limited by the modest correction of conventional near-IR optimized AO systems. We take advantage of new fast and low-readout-noise detectors to explore the potential of fast imaging coupled to postprocessing techniques to detect faint companions of stars at small angular separations. Aims. We have focused on I-band direct imaging of the previously detected brown dwarf binary HD 130948 BC, attempting to spatially resolve the L2+L2 system considered as a benchmark for the determination of substellar objects dynamical masses. Methods. We used the lucky-imaging instrument FastCam at the 2.5-m Nordic Telescope to obtain quasi diffraction-limited images of HD 130948 with ∼0.1 �� resolution. In order to improve the detectability of the faint binary in the vicinity of a bright (I = 5.19 ± 0.03) solar-type star, we implemented a post-processing technique based on wavelet transform filtering of the image, which allows us to strongly enhance the presence of point-like sources in regions where the primary halo generally dominates. Results. We detect for the first time the binary brown dwarf HD 130948 BC in the optical band I with a SNR ∼ 9 at 2.561 �� ± 0.007 �� (46.5 AU) from HD 130948 A and confirm in two independent datasets (2008 May 29 and July 25) that the object is real, as opposed to time-varying residual speckles. We do not resolve the binary, which can be explained by astrometric results posterior to our observations, which predict a separation below the telescope resolution. We reach a contrast of ΔI = 11.30 ± 0.11 at this distance, and estimate a combined magnitude for this binary I = 16.49 ± 0.11 and a I − J color of 3.29 ± 0.13. At 1 �� , we reach a detectability 10.5 mag fainter than the primary after image post-processing. Conclusions. We obtain on-sky validation of a technique based on speckle imaging and wavelet-transform post-processing, which improves the high-contrast capabilities of speckle imaging. The I − J color measured for the BD companion is slightly bluer, but still consistent with what is typically found for L2 dwarfs (∼3.4–3.6).
幸运的是自适应光学：使用大型望远镜在可见光中快速自适应光学图像选择
DOI：
10.1088/0004-637x/692/1/924
发表时间：
2009
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Law N
通讯作者：
Law N