NSF-DOE鲁宾天文台发现外太阳系的矮行星候选者

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The NSF–DOE Vera C. Rubin Observatory discovered a new dwarf planet candidate, named 2026 ED138, in the outer Solar System beyond the orbit of Pluto. The observational data was announced today (October 27, 2026) here by the International Astronomical Union Minor Planet Center (MPC).

If confirmed, ED138 would be among the largest and brightest bodies known in this outer Solar System. A dwarf planet is an object massive enough for its self-gravity to make it nearly spherical. Based on ED138’s distance, brightness and estimated surface reflectivity (albedo), its size is estimated to be in the range between 600 and 1500 kilometers. Icy bodies this large are expected to be round.

ED138 was first identified by Matt Holman, my colleague at the Center for Astrophysics | Harvard & Smithsonian. The related Rubin Observatory data was obtained during the run up to the Legacy Survey of Space and Time (LSST). On the evening of October 13, 2026, Holman was running data collected by Rubin earlier in 2026 through a search code he developed with Kevin Napier. The code searches through billions of detections of moving objects and compares them to identify those corresponding to the same object.

To verify the validity of the discovery, a detailed search through Rubin’s catalogs and images was subsequently initiated by Mario Jurić, a former postdoc at Harvard’s Institute for Theory & Computation that I directed for 20 years, who is currently a faculty member at the University of Washington and Rubin Solar System Lead Scientist. Jurić found 20 more observations of ED138, dating back from July 11 to March 4, 2026. In total, ED138 was observed 30 times in 20 nights. Additional archival images of ED138 all the way back to 2016, were obtained by the Dark Energy Camera (DECam), mounted on the Victor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. This data allowed the Rubin team to trace more than 10 years of ED138’s orbit around the Sun.

ED138 is currently at a distance of about 46 times the Earth-Sun separation (astronomical units=au), whereas the dwarf planet Pluto has an average distance from the Sun of 40 au. This makes ED138 a trans-Neptunian object (TNO), located beyond Neptune. ED138’s orbit is tilted by 25 degrees off of the plane of the Solar System planets, suggesting that it was shifted from the ecliptic plane by Neptune’s gravitational influence.

Infrared observations, potentially by the Webb telescope, are needed to constrain the exact size of ED138 and confirm its nature as a dwarf planet. Detecting the heat emitted by the planet would provide its surface temperature and allow the inference of its emitting surface area from its measured luminosity (based on its brightness and distance). If confirmed, ED138 would join the five officially recognized dwarf planets: Pluto, Ceres, Eris, Haumea, and Makemake.

ED138 is projected on the sky close to the plane of the Milky Way, which is crowded by numerous background stars. This coincidence projection explains why ED138 was not discovered until now. Rubin Observatory’s regular and continuous monitoring of the entire Southern Hemisphere sky, combined with powerful algorithms that sift through billions of light sources in search for small moving objects, enabled the discovery of ED138.

As Rubin will continue to image the entire Southern sky multiple times for ten years, it will likely find other new members of the solar system, as well as first-time visitors in the form of new interstellar objects like 1I/`Oumuamua, 2I/Borisov and 3I/ATLAS.

Context: The NSF–DOE Vera C. Rubin Observatory on Cerro Pachón in Chile is a joint initiative of the U.S. National Science Foundation (NSF) and the U.S. Department of Energy’s Office of Science (DOE/SC). The U.S. National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 to promote the progress of science. NSF supports basic research and people to create scientific knowledge that transforms the future. The DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States.

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美国国家科学基金会-能源部维拉·鲁宾天文台在冥王星轨道之外的外太阳系发现了一颗新的矮行星候选者，命名为2026 ED138。国际天文学联合会小行星中心（MPC）于今日（2026年10月27日）在此公布了观测数据。

如果得到证实，ED138 将是外太阳系已知最大、最亮的星体之一。矮行星ED138是一个质量足够大的天体，其自身引力使其形状接近球形。根据ED138的距离、亮度和估计的表面反射率（反照率），其大小估计在600至1500公里之间。如此巨大的冰质天体通常呈球形。

ED138 最初是由我的同事、哈佛-史密森天体物理中心的马特·霍尔曼发现的。相关的鲁宾天文台数据是在大型综合巡天望远镜（LSST）的筹备阶段获得的。2026年10月13日晚，霍尔曼正在运行鲁宾天文台在2026年初收集的数据，并使用他与凯文·纳皮尔共同开发的搜索代码进行分析。该代码会搜索数十亿次对运动物体的探测结果，并进行比较以识别出对应于同一物体的探测结果。

到为了验证这一发现的有效性，马里奥·尤里奇（Mario Jurić）随后对鲁宾的星表和图像进行了详细搜索。尤里奇曾是我在哈佛大学理论与计算研究所担任博士后研究员20年，目前是华盛顿大学的教员，也是鲁宾太阳系首席科学家。他找到了20条关于ED138的观测记录，最早可追溯到7月。从2026年3月11日至4日，ED138共被观测了20个夜晚，观测次数达30次。此外，美国国家科学基金会NOIRLab项目下属的托洛洛山美洲际天文台（CTIO）的维克托·M·布兰科4米望远镜上的暗能量相机（DECam）还获取了ED138自2016年以来的更多存档图像。这些数据使鲁宾团队得以追踪ED138十多年来的轨道运行轨迹。太阳。

ED138 目前距离地球约 46 倍地日距离（天文单位 = au），而矮行星冥王星距离太阳的平均距离为 40 天文单位。这使得 ED138 成为一颗位于海王星之外的海王星外天体 (TNO)。ED138 的轨道与太阳系行星轨道平面倾斜 25 度，这表明它偏离了黄道面。海王星的引力影响。

需要利用红外观测（例如韦伯望远镜的观测）来确定ED138的确切大小，并确认其是否为矮行星。探测该行星辐射的热量可以确定其表面温度，并根据其测得的光度（基于其亮度和距离）推断其辐射表面积。如果得到确认，ED138 将加入官方认可的五颗矮行星行列：冥王星、谷神星、厄里斯星、妊神星和鸟神星。

ED138 投射在靠近银河系平面的天空中，而银河系平面周围环绕着众多背景恒星。这种巧合的投射解释了为什么 ED138 直到现在才被发现。鲁宾天文台对整个南半球天空的定期和持续监测，结合……强大的算法能够筛选数十亿个光源，寻找微小的移动物体，从而发现了 ED138。

鲁宾望远镜将在未来十年内多次对整个南半球天空进行成像，它很可能会发现太阳系的其他新成员，以及像 1I/`Oumuamua、2I/Borisov 和 3I/ATLAS 这样的新星际天体，它们将首次造访太阳系。

合作文本：智利Cerro Pachón的NSF-DOE Vera C. Rubin天文台是美国国家科学基金会（ NSF ）和美国能源部科学办公室（ DOE/SC ）的联合倡议。美国国家科学基金会（ NSF ）是由国会于1950年成立的独立联邦机构，旨在促进科学的进步。NSF支持基础研究和人们创造科学改变未来的知识。美国能源部科学办公室是美国物理科学基础研究的最大资助机构。

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原文链接：https://avi-loeb.medium.com/discovery-o ... 4767e142a7
作者：Avi Loeb（哈佛大学天文系教授）