- Galaxy NGC 300 is a Milky Way look-alike
- Inside is a black hole devouring a nearby star
- On track for a collision with another galaxy
A galaxy very similar to our own Milky Way is shown in brilliant colour in a new image just released.
Spiral galaxy NGC 300 is about six million light-years away, and—if it could be seen with the naked eye—would span almost two-thirds the width of the full Moon on the sky.
Discovered from Australia by the Scottish astronomer James Dunlop early in the 19th century, NGC 300 is one of the closest and most prominent spiral galaxies in the southern skies and is bright enough to be seen through binoculars.
It lies in the inconspicuous constellation Sculptor, which has very few bright stars. Sculptor’s main claim to fame is that it is home to a collection of nearby galaxies that form the Sculptor Group.
While many galaxies have at least some slight peculiarity, on the surface NGC 300 seems to be remarkably normal, making it an ideal specimen for astronomers studying the structure and content of spiral galaxies such as our own.
The picture—taken with the Wide Field Imager (WFI) at European Southern Observatory’s La Silla Observatory in Chile—was assembled from many individual images taken through a large set of different filters with a total exposure time close to 50 hours. This enormous amount of data was acquired over many observing nights, spanning several years.
More detail than meets the eye
The main purpose of this imaging campaign was to take an unusually thorough census of the stars in the galaxy…counting both the number and varieties of the stars, and marking regions, or even individual stars, that warrant deeper and more focussed investigation.
But such a rich data collection brings out other detail.
For instance, by imaging the galaxy with filters that isolate the light coming specifically from hydrogen and oxygen, the many intense star-forming regions along NGC 300’s spiral arms are shown with particular clarity as angry, red and pink clouds.
NGC 300 is also home to the most distant and one of the most massive stellar-mass black holes yet found. The black hole is partnered with a hot and luminous Wolf–Rayet star in a binary system—the hot star is being gradually consumed by the black hole.
And NGC 300 is on track for a violent end. It and another galaxy, NGC 55, are slowly spinning around and towards each other, in the early stages of a lengthy merger process.
And although it is normally considered as member of the Sculptor Group, the most recent distance measurements show that NGC 300 is significantly closer to us than many of the other galaxies in the group, and therefore may be only loosely associated with them.
Adapted from information issued by ESO / L. Calçada / M.Kornmesser.
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