Dept. of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ, USA.
NASA Nexus for Exoplanet System Science, Earths in Other Solar Systems Team, Tucson, AZ, USA.
Nat Commun. 2021 Feb 10;12(1):922. doi: 10.1038/s41467-021-21176-6.
Giant exoplanets on wide orbits have been directly imaged around young stars. If the thermal background in the mid-infrared can be mitigated, then exoplanets with lower masses can also be imaged. Here we present a ground-based mid-infrared observing approach that enables imaging low-mass temperate exoplanets around nearby stars, and in particular within the closest stellar system, α Centauri. Based on 75-80% of the best quality images from 100 h of cumulative observations, we demonstrate sensitivity to warm sub-Neptune-sized planets throughout much of the habitable zone of α Centauri A. This is an order of magnitude more sensitive than state-of-the-art exoplanet imaging mass detection limits. We also discuss a possible exoplanet or exozodiacal disk detection around α Centauri A. However, an instrumental artifact of unknown origin cannot be ruled out. These results demonstrate the feasibility of imaging rocky habitable-zone exoplanets with current and upcoming telescopes.
天文学家已经直接拍摄到了围绕年轻恒星运行的大型系外行星。如果能减轻中红外热背景的影响，那么质量较低的系外行星也可以成像。在这里，我们提出了一种基于地面的中红外观测方法，能够对附近恒星周围的低质量温和系外行星进行成像，特别是在半人马座阿尔法星这一最近的恒星系统内。基于 100 小时累计观测中 75-80%的最佳质量图像，我们证明了在半人马座阿尔法星 A 的整个可居住区都能探测到温暖的亚海王星大小的行星。这比最先进的系外行星成像质量探测极限灵敏一个数量级。我们还讨论了在半人马座阿尔法星 A 周围可能存在的系外行星或黄道带尘埃盘的探测。然而，一种未知来源的仪器artifact 尚无法排除。这些结果表明，使用当前和未来的望远镜对岩石宜居带系外行星进行成像具有可行性。
