The Distant Globular of Camelopardalis
This week’s OOTW features JeanTate’s OOTD posted on the 22nd of September.
This object has the inventive name of F46 and it lives in the constellation Camelopardalis. It’s not a star, but is in fact a cluster of stars; a globular cluster. It’s not in our galaxy unlike most globular clusters we observe in the night sky, but lies 11 million light years away in the outskirts of NGC 2403; a spiral galaxy that William Herschel discovered in 1788.
Globular clusters are balls of thousands of old stars gravitationally bound to each other. They orbit their galaxy around the centre, but instead of following the normal path that most stars take – such as in the disks of spiral galaxies – they orbit their galaxy in the galactic halo, which stretches out farther than what is visible in the image above as a sphere, placing the globulars as much as 100,000 light years away from the centre.
F46, being magnitude v 18, is the brightest globular in NGC 2403. But there are plenty more unseen (as far as I can tell) in this SDSS image which you can see in this lovely Hubble image here. Our own galaxy has around 150 or so globular clusters, but many more galaxies have a much higher number; elliptical galaxies for instance have thousands!