Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE
Closing the gap between Earth-based and interplanetary mission observations: Vesta seen by VLT/SPHERE
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DOI：
10.1051/0004-6361/201834749
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发表时间：
2019-02
影响因子：
6.5
通讯作者：
R. F'etick;L. Jorda;P. Vernazza;M. Marsset;A. Drouard;Thierry Fusco;B. Carry;F. Marchis;J. Hanuš;M. Viikinkoski;M. Birlan;P. Bartczak;J. Berthier;J. Castillo-Rogez;F. Cipriani;F. Colas;G. Dudziński;C. Dumas;M. Ferrais;E. Jehin;M. Kaasalainen;A. Kryszczyńska;P. Lamy;H. Coroller;A. Marciniak;T. Michałowski;P. Michel;L. Mugnier;B. Neichel;M. Pajuelo;E. Podlewska-Gaca;T. Santana-Ros;P. Tanga;F. Vachier;A. Vigan;O. Witasse;Bin Yang
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文献类型：
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作者：
R. F'etick;L. Jorda;P. Vernazza;M. Marsset;A. Drouard;Thierry Fusco;B. Carry;F. Marchis;J. Hanuš;M. Viikinkoski;M. Birlan;P. Bartczak;J. Berthier;J. Castillo-Rogez;F. Cipriani;F. Colas;G. Dudziński;C. Dumas;M. Ferrais;E. Jehin;M. Kaasalainen;A. Kryszczyńska;P. Lamy;H. Coroller;A. Marciniak;T. Michałowski;P. Michel;L. Mugnier;B. Neichel;M. Pajuelo;E. Podlewska-Gaca;T. Santana-Ros;P. Tanga;F. Vachier;A. Vigan;O. Witasse;Bin Yang
语境。在过去的几十年里，多项行星际任务对小天体进行了原位研究，使我们对其地质和地球物理特性的理解取得了重大进展。然而，这些任务的目标数量有限。其中，NASA 黎明任务详细描述了小行星 (4) 灶神星表面的地形和反照率变化，空间分辨率达到约 20 m 像素−1 尺度。目标。在这里，我们的目标是确定在灶神星的情况下，VLT/SPHERE 可以从地面检索多少地形和反照率信息，之前的太空任务（黎明）为我们提供了可以用作基准的地面实况。方法。作为我们 ESO 大型计划 (ID 199.C-0074) 的一部分，我们使用 VLT/SPHERE/ZIMPOL 在六个不同时期观察灶神星，并使用参数点扩散函数 (PSF) 对收集到的图像进行去卷积。然后，我们将我们的图像与黎明任务的 3D 形状模型生成的灶神星合成视图进行比较，我们在其上投影了灶神星的反照率信息。结果。我们表明，使用参数化 PSF 对 VLT/SPHERE 图像进行反卷积可以检索灶神星表面存在的主要地形和反照率特征，空间分辨率可达约 20-30 公里。轮廓提取的精度约为 1 像素 (3.6 mas)。本研究首次对小行星表面的地面自适应光学成像观测的准确性进行了定量估计。结论。就灶神星而言，下一代 30-40 m 望远镜（ELT、TMT、GMT）原则上应该能够解析其表面的所有主要特征，包括海槽和南北陨石坑二分法，前提是它们在衍射极限下运行。
Context. Over the past decades, several interplanetary missions have studied small bodies in situ, leading to major advances in our understanding of their geological and geophysical properties. These missions, however, have had a limited number of targets. Among them, the NASA Dawn mission has characterised in detail the topography and albedo variegation across the surface of asteroid (4) Vesta down to a spatial resolution of ~20 m pixel−1 scale. Aims. Here our aim was to determine how much topographic and albedo information can be retrieved from the ground with VLT/SPHERE in the case of Vesta, having a former space mission (Dawn) providing us with the ground truth that can be used as a benchmark. Methods. We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO large programme (ID 199.C-0074) at six different epochs, and deconvolved the collected images with a parametric point spread function (PSF). We then compared our images with synthetic views of Vesta generated from the 3D shape model of the Dawn mission, on which we projected Vesta’s albedo information. Results. We show that the deconvolution of the VLT/SPHERE images with a parametric PSF allows the retrieval of the main topographic and albedo features present across the surface of Vesta down to a spatial resolution of ~20–30 km. Contour extraction shows an accuracy of ~1 pixel (3.6 mas). The present study provides the very first quantitative estimate of the accuracy of ground-based adaptive-optics imaging observations of asteroid surfaces. Conclusions. In the case of Vesta, the upcoming generation of 30–40 m telescopes (ELT, TMT, GMT) should in principle be able to resolve all of the main features present across its surface, including the troughs and the north–south crater dichotomy, provided that they operate at the diffraction limit.