Many of the best-loved galaxies in the cosmos are remarkably large, close, massive, bright, or beautiful, often with an unusual or intriguing structure or history. However, it takes all kinds to make a universe — as demonstrated by this Hubble image of Messier 110.
Messier 110 may not look like much, but it is a fascinating near neighbor of our home galaxy, and an unusual example of its type. It is a member of the Local Group, a gathering of galaxies comprising the Milky Way and a number of the galaxies closest to it. Specifically, Messier 110 is one of the many satellite galaxies encircling the Andromeda galaxy, the nearest major galaxy to our own, and is classified as a dwarf elliptical galaxy, meaning that it has a smooth and almost featureless structure. Elliptical galaxies lack arms and notable pockets of star formation — both characteristic features of spiral galaxies. Dwarf ellipticals are quite common in groups and clusters of galaxies, and are often satellites of larger galaxies.
Because they lack stellar nurseries and contain mostly old stars, elliptical galaxies are often considered “dead” when compared to their spiral relatives. However, astronomers have spotted signs of a population of young, blue stars at the center of Messier 110 — hinting that it may not be so “dead” after all.
Messier 110 is featured in Hubble’s Messier catalog, which includes some of the most fascinating celestial objects that can be observed from Earth’s Northern Hemisphere. See the NASA-processed image and other Messier objects at: https://www.nasa.gov/content/goddard/hubble-s-messier-catalog.
Text credit: ESA (European Space Agency)
Image credit: ESA/Hubble & NASA, L. Ferrarese et al.
Messier 110可能看起来不太像，但它是我们的母星系的一个迷人的近邻，也是它类型的一个不寻常的例子。它是一个局部星系群的成员，这个星系群由银河系和一些离它最近的星系组成。具体来说，Messier 110是环绕仙女座星系的众多卫星星系之一，仙女座星系是离我们最近的主要星系，被归类为矮椭圆星系，这意味着它有一个光滑的几乎没有特征的结构。椭圆星系缺少臂和明显的恒星形成区——这两个特征都是螺旋星系的特征。矮椭圆星系在星系群和星系团中很常见，通常是较大星系的卫星。
资料来源:ESA (European Space Agency)
图片来源: ESA/Hubble & NASA, L. Ferrarese et al.