Triangulum Galaxy

Hubble Telescope captures huge picture of nearby galaxy

Image credit: pa

The Hubble Space Telescope has captured the most detailed image yet of a close neighbour of the Milky Way: the Triangulum Galaxy, a spiral galaxy located at a distance of only three million light-years.

The 40-billion-star galaxy is one of the most distant objects visible to the naked eye. Under dark-sky conditions, it appears as a faint, blurry object in the constellation of Triangulum (the Triangle) and is a popular target for amateur astronomers.

This new image contains a vast 665 million pixels and showcases the central region of the galaxy and its inner spiral arms. To stitch together this gigantic mosaic, Hubble's Advanced Camera for Surveys needed to create 54 separate images.

Along with the Andromeda Galaxy and our own Milky Way, Triangulum forms part of what is known as the Local Group - a collection of more than 50 galaxies bound together by gravity.

According to the ESA, it is the group’s third-largest galaxy, but also its smallest spiral galaxy. It measures only about 60,000 light years across, compared to the 200,000 light years of the much bigger spiral Andromeda Galaxy. By comparison, the spiral Milky Way is about 100,000 light years in diameter. The remaining members of the Local Group are dwarf galaxies, each orbiting one of the three larger ones.

In contrast to the two larger spiral galaxies, Triangulum does not have a bright bulge at its centre, and it lacks a bar connecting its spiral arms to the centre.

The abundance of gas clouds in the Triangulum Galaxy is what drew astronomers to conduct this detailed survey. When stars are born, they use up material in these clouds of gas and dust, leaving less fuel for new stars to emerge. New stars form at a rate of approximately one solar mass every two years.

One area of the Triangulum Galaxy, NGC 604, is among the largest known star formation regions in the Local Group, the ESA said.

Releasing the detailed image of Triangulum, the ESA added: “These detailed observations of the Triangulum Galaxy have tremendous legacy value - combined with those of the Milky Way, the Andromeda Galaxy and the irregular Magellanic Cloud galaxies, they will help astronomers to better understand star formation and stellar evolution.”

The Andromeda Galaxy was mapped by Hubble in 2015, creating the sharpest and largest image of this galaxy and the largest Hubble image ever.

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