Hubble shows Triangulum galaxy where stars are forming

The most detailed image of a 40-billion-star galaxy where stars are still forming has been captured by the Hubble Space Telescope.

This ultra-high-pixel image of the Triangulum Galaxy — also known as Messier 33 — is a composite of about 54 different pointings with Hubble’s Advanced Camera for Surveys. It is the second-largest image released by Hubble, behind only the image of the Andromeda Galaxy, released in 2015. Picture: NASA/ESA

The most detailed image yet of a 40-billion-star neighbouring galaxy has been captured by the Hubble Space Telescope.

The Triangulum Galaxy, located three million light years away from the Milky Way, 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 target for amateur astronomers.

But in a new 665-million-pixel image taken by the NASA/European Space Agency (ESA) Hubble Space Telescope, the spiral galaxy’s billions of stars are brightly showcased.

The spectacular vista is in fact a giant mosaic, formed from 54 separate images created by Hubble’s Advanced Camera for Surveys.

The Hubble Space Telescope above Earth. Picture: NASA/ESA

As the second-largest image ever released by Hubble, it encompasses the central region of the galaxy and its inner spiral arms.

Millions of stars, hundreds of star clusters and bright nebulae are visible. Triangulum, also known as Messier 33 or NGC 598, is part of the Local Group — a collection of more than 50 galaxies, including the Milky Way, that are 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 with 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. In contrast to the two larger spiral galaxies, Triangulum does not have a bright bulge at its centre — and it also lacks a bar connecting its spiral arms to the centre.

This image from NASA/ESA shows NGC 604, located within the Triangulum Galaxy. About 1500 light years across, this is one of the largest, brightest concentrations of ionised hydrogen in the so-called Local Group of galaxies, and it is a major centre of star formation. The gas is gradually collapsing under the force of gravity to create new stars.

The ESA said the galaxy contained a huge amount of gas and dust, giving rise to rapid star formation.

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

AAP-PA