Leo Ring

The name given to a vast ring of hydrogen and helium within the Leo I Group of galaxies, approximately thirty-eight million light years from the Milky Way. The ring is thought to have originated in the collision of two galaxies at the heart of the group, M105 and NGC 3384, more than a billion years ago. The galaxies themselves survived their dramatic interaction, but much of their interstellar gas was stripped away and cast into space, and has since been expanding outward to create the Leo Ring.

The ring takes the form of an elongated ellipse, somewhat broken on its northern edge, that has reached a diameter of some 650,000 light years (equivalent to about six times the diameter of the Milky Way). Its southern edge now approaches another galaxy within the group, M96, and the gases of the ring have distorted to form a band that extends outward towards that galaxy, giving the entire ring structure, seen in radio wavelengths, the appearance of an immense letter 'Q' in space. There are indications that local regions within the ring are in the process of collapsing to form new dwarf galaxies and, within these young galaxies, the ring's hydrogen and helium is condensing to form new generations of stars.