This NASA/ESA Hubble Space Telescope image features the globular cluster Messier 72 (M72).
ESA/Hubble & NASA, A. Sarajedini, G. Piotto, M. Libralato
As part of ESA/Hubble’s 35th anniversary celebrations, the European Space Agency (ESA) shared new images that revisited stunning, previously released Hubble targets with the addition of the latest Hubble data and new processing techniques.
ESA/Hubble released new images of NGC 346, the Sombrero Galaxy, and the Eagle Nebula earlier in the month. Now they are revisiting the star cluster Messier 72 (M72).
M72 is a collection of stars, formally known as a globular cluster, located in the constellation Aquarius roughly 50,000 light-years from Earth. The intense gravitational attraction between the closely packed stars gives globular clusters their regular, spherical shape. There are roughly 150 known globular clusters associated with the Milky Way galaxy.
The striking variety in the color of the stars in this image of M72, particularly compared to the original image, results from the addition of ultraviolet observations to the previous visible-light data. The colors indicate groups of different types of stars. Here, blue stars are those that were originally more massive and have reached hotter temperatures after burning through much of their hydrogen fuel; the bright red objects are lower-mass stars that have become red giants. Studying these different groups help astronomers understand how globular clusters, and the galaxies they were born in, initially formed.
Pierre Méchain, a French astronomer and colleague of Charles Messier, discovered M72 in 1780. It was the first of five star clusters that Méchain would discover while assisting Messier. They recorded the cluster as the 72nd entry in Messier’s famous collection of astronomical objects. It is also one of the most remote clusters in the catalog.
这张由美国国家航空航天局（NASA）和欧洲航天局（ESA）合作的哈勃太空望远镜拍摄的图像展示了球状星团M72（Messier 72）。
图片来源: ESA/Hubble & NASA, A. Sarajedini, G. Piotto, M. Libralato
作为欧洲航天局/哈勃成立35周年庆祝活动的一部分，欧洲航天局分享了多张重新处理的壮丽图像，这些图像基于哈勃望远镜先前公布的经典目标，结合了最新的哈勃观测数据与先进的图像处理技术。
本月早些时候，欧洲航天局/哈勃已发布了NGC 346、草帽星系（Sombrero Galaxy）以及鹰状星云（Eagle Nebula）的新版图像。此次，他们又重新探访了恒星星团——M72。
M72是一个恒星密集的集合体，正式名称为球状星团，位于宝瓶座，距离地球约5万光年。球状星团中恒星之间强大的引力作用使其呈现出规则的球形结构。目前，天文学家已知大约有150个球状星团与银河系相关联。
在此次重新处理的M72图像中，星星呈现出丰富的色彩变化，尤其是与原始图像相比更为显著。这种变化得益于在原有可见光观测基础上加入了紫外线观测数据。不同颜色反映了不同类型的恒星群体：蓝色恒星通常起源于质量较大的恒星，在消耗了大量氢燃料后达到更高的温度；而明亮的红色天体则是质量较小、已演化为红巨星的恒星。通过研究这些不同类型的恒星，天文学家能够更好地理解球状星团的形成过程以及它们诞生所在的星系的早期演化历史。
M72由法国天文学家皮埃尔·梅尚（Pierre Méchain）于1780年发现。他是著名天文学家查尔斯·梅西耶（Charles Messier）的同事，也是五个由梅尚发现并录入梅西耶星表的星团之一。M72最终成为梅西耶著名天体目录中的第72号天体，也是该目录中距离地球最远的星团之一。
