Nearly a decade after discovering LHS 1140b, a rocky exoplanet in the habitable zone of a nearby low-mass star, a new study reveals the object may have its own atmosphere. University of Florida Assistant Professor of Astronomy Jason Dittmann, Ph.D., first discovered the planet in 2016. Now, he is co-author of the new study, published in Science, that uses helium escape to explain a potential atmosphere. “This is the first time that we’re seeing a rocky, Earth-like planet that could still have an atmosphere.” Dittmann said. The Magellan Clay telescope at Las Campanas Observatory in Chile showed proof of helium escaping from the planet. However, the planet’s age signals it would have run out of helium unless it was replenishing its own supply, pointing to the potential of an atmosphere. In 2016, Dittmann used ground-based surveys to search for stars whose light briefly dimmed as orbiting planets passed in front of them. However, observing from the ground allows for Earth’s atmosphere to confuse this process. To understand if the stars were dimming due to wispy clouds or humidity blowing through on Earth, he trained a machine learning algorithm to decipher which signals were caused by Earth’s weather and which were because of a passing planet. The method helped Dittmann find LHS 1140b. The planet’s orbit meant it could only be observed a few times a year, so he tried to make the most of the limited opportunities he had to study it. Considering the type of star it orbits, Dittmann said the planet’s temperature should be similar to Earth’s. It’s made of rock instead of gas, is approximately 40 light years away. There is also a second planet in the system, LHS 1140c, which is located outside the habitable zone of its system. Other rocky planets discovered within the past decade or so lost their atmospheres over time. Considering the age of LHS 1140b and the lack of atmospheres by similar planets, Dittmann and the team didn’t expect to find helium. LHS 1140b was different. After originally discovering the planet, Dittmann quickly requested X-ray data from the planetary system. This gave him the energy input from the star into the planet, which became key to interpreting the helium signal years later. The Magellan Clay telescope later revealed helium escaping from the planet, a process that also occurs on Earth. The X-ray data explained the rate at which the planet lost its helium because of the X-ray radiation from the host star. Therefore, the X-ray data proved the rocky object must be replenishing its supply of helium; if it wasn’t, there would be no helium remaining. The team started by asking for helium observations because it is easiest to spot. But now that there is potential proof of an atmosphere, the group of scientists can start looking at carbon dioxide and water to further test the planet’s conditions. 在对近邻低质量恒星宜居带内的岩石系外行星LHS 1140b的发现过去近十年后，一项新研究揭示，这颗天体可能拥有自己的大气层。 佛罗里达大学天文学助理教授杰森·迪特曼博士于2016年首次发现该行星。如今，他作为合著者参与了发表在《科学》杂志上的这项新研究，该研究利用氦逃逸来解释潜在的大气层存在。 迪特曼表示：“我们第一次看到一颗类地的岩石行星可能仍然拥有大气层。” 位于智利拉斯坎帕纳斯天文台的麦哲伦克莱望远镜观测到了氦从该行星逃逸的证据。然而，行星的年龄意味着，除非它自身在补充供应，否则氦早已耗尽，这指向了大气层存在的可能性。 2016年，迪特曼利用地面巡天观测，寻找那些因绕行行星从前方经过而导致星光短暂变暗的恒星。 但地面观测会受到地球大气层的干扰。为了辨别恒星变暗是由于地球上的薄云或湿气所致，还是因为行星过境，他训练了一种机器学习算法，用以区分哪些信号由地球天气引起，哪些由过境行星导致。 这一方法帮助迪特曼发现了LHS 1140b。该行星的轨道意味着每年只能观测到几次，因此他尽力充分利用有限的研究机会。 考虑到它所绕行恒星的类型，迪特曼表示该行星的温度应与地球相似。它由岩石而非气体构成，距离地球约40光年。该系统中还有第二颗行星LHS 1140c，位于其系统的宜居带之外。 过去十年左右发现的其他岩石行星，其大气层大多已随时间消失。考虑到LHS 1140b的年龄以及类似行星普遍缺乏大气层的状况，迪特曼和研究团队原本并未预料到会发现氦。 但LHS 1140b与众不同。 最初发现该行星后，迪特曼迅速申请了该行星系统的X射线数据。这使他获得了恒星输入行星的能量数据，这些数据后来成为解读氦信号的关键。 麦哲伦克莱望远镜后来观测到氦从行星逃逸，这一过程在地球上同样发生。X射线数据解释了行星因宿主恒星的X射线辐射而损失氦的速率。因此，X射线数据证明这颗岩石天体必定在补充其氦储备；否则，氦早已不复存在。 研究团队起初之所以提出氦观测请求，是因为氦最容易探测。但现在，既然已有大气层的潜在证据，科学家们可以开始关注二氧化碳和水，以进一步检验该行星的状况。 (Translated by DeepSeek) | 