智利望远镜发现冥王星轨道外可能的新矮行星 记者 威尔·邓纳姆 华盛顿，10月28日电 科学家利用一台位于智利的望远镜，在冥王星轨道之外发现了一颗冰质天体，它可能成为太阳系矮行星名单中的新成员。
Possible new dwarf planet identified orbiting beyond Pluto By Will Dunham WASHINGTON, Oct 28 - Scientists using a Chile-based telescope have identified an icy object orbiting beyond Pluto that may join our solar system's small roster of dwarf planets.
研究人员表示，这颗候选天体被命名为2026 ED138，其直径估计在370至930英里（约600至1500公里）之间，距离太阳约为地日距离的46倍。相比之下，冥王星平均距离太阳约为地日距离的40倍。
Researchers said the candidate, named 2026 ED138, has a diameter estimated at between roughly 370 and 930 miles (600 and 1,500 km) and is orbiting about 46 times farther from the sun than Earth. By way of comparison, Pluto orbits at an average of about 40 times farther from the sun than Earth.
该天体是通过位于智利中部帕琼山顶的薇拉·C·鲁宾天文台新望远镜发现的。该望远镜是美国国家科学基金会和美国能源部的联合项目。还需要进一步观测以确认该天体是否为矮行星。
The object was spotted using the new Vera C. Rubin Observatory, on the summit of the Cerro Pachón mountain in central Chile. The telescope is a joint initiative of the US National Science Foundation and US Department of Energy. Further observations are needed to confirm that the object is a dwarf planet.
如果得到确认，2026 ED138将加入国际天文学联合会（作为天体分类的全球权威机构）认定的其他五颗矮行星行列。这五颗分别是冥王星、阋神星、妊神星和鸟神星——它们都位于最外层行星海王星轨道之外——以及位于火星和木星之间主小行星带的谷神星。
If confirmed, 2026 ED138 would join five other dwarf planets recognized by the International Astronomical Union, the global authority on classifying celestial bodies. Those are Pluto, Eris, Haumea and Makemake, all of which orbit beyond the outermost planet Neptune, and Ceres, located in the main asteroid belt between Mars and Jupiter.
根据目前的数据，2026 ED138将位列最大的矮行星之中。
Based on the current data, 2026 ED138 would be among the largest of the dwarf planets.
哈佛-史密松天体物理中心的天体物理学家马特·霍尔曼最先发现了2026 ED138，他说：“对我来说，这表明利用鲁宾天文台和其他望远镜仍有许多令人振奋的发现有待揭示。”
"For me, what this demonstrates is that many exciting discoveries remain to be made with the Rubin Observatory and other telescopes," said astrophysicist Matt Holman of the Center for Astrophysics, Harvard & Smithsonian, who first spotted 2026 ED138.
冥王星长期以来被视为太阳系的第九颗、也是最外层的行星，但因不符合国际天文学联合会对行星的正式定义，于2006年被重新归类为矮行星。冥王星和这颗新的矮行星候选天体都位于太阳系一个寒冷区域，该区域分布着各种冰质天体。
Pluto long was considered the solar system's ninth and outermost planet, but was reclassified by the International Astronomical Union as a dwarf planet in 2006 because it did not meet the organization's formal definition of a planet. Pluto and the new dwarf planet candidate reside in a frigid region of the solar system populated by various icy bodies.
关于2026 ED138的大小和成分仍存在疑问。要被认定为矮行星，天体必须拥有足够的质量，使其自身的引力将其拉成球形。2026 ED138似乎具备足够的质量，但仍需更多观测。
There are still questions about the size and composition of 2026 ED138. To be considered a dwarf planet, an object must possess sufficient mass for its own gravity to pull it into a round shape. 2026 ED138 appears to have sufficient mass for that, but more observations are needed. "The main thing we need to do is to establish the physical size of 2026 ED138," Holman said.
“我们目前最需要做的是确定2026 ED138的物理尺寸，”霍尔曼说。
"When we observe with Rubin, we are seeing the sun's light reflected from the object," Holman said.
“当我们用鲁宾天文台观测时，看到的是太阳光从该天体表面反射的光，”霍尔曼说。“一个较小但反射率较高的天体，反射的光量可能与一个较大但反射率较低的天体相同。幸运的是，通过在更长波长下观测，利用阿塔卡马大型毫米波/亚毫米波阵列（ALMA）这样的天文台，我们可以探测到天体自身发出的光，”这有助于测量天体的大小。
"A smaller, more reflective object would show the same amount of light as a larger, less reflective object. Fortunately, by looking at longer wavelengths, with an observatory like ALMA, we can detect the light emitted by the object itself," which is helpful in measuring an object's size.
阿塔卡马大型毫米波/亚毫米波阵列（ALMA）是一座同样位于智利的强大望远镜。这一发现是在华盛顿州斯波坎举行的一次科学会议上宣布的。
ALMA, or the Atacama Large Millimeter/submillimeter Array, is a powerful telescope also based in Chile. The discovery was announced at a scientific meeting in Spokane, Washington.