Just 500 parsecs away, a giant supernova remnant was hiding in plain sight. Invisible to your everyday telescope, this object shines in the X-ray sky with an apparent size of four degrees. This is a middle-aged remnant, that might appear like the Vela nebula if it were differently located. This object was found with the eROSITA All-Sky Survey and will be published in a new paper in Astronomy & Astrophysics. This research was led by Werner Becker, who named this object Hoinga, which happens to be the medieval name of Becker’s German hometown.  

While it is a bit disturbing to realize the second-largest supernova remnant in the sky has been hanging out unseen for so long, it isn’t actually surprising. It’s estimated that galaxies like our own Milky Way should contain about 1,200 supernova remnants, but so far, we’ve only found about three hundred. The majority of these are invisible to optical telescopes and have instead been discovered with radio telescopes, and now with X-ray facilities. The eROSITA All-sky Survey is specifically designed to search supernova remnants like this one, and in the coming years, hopefully, we will find a lot more of the remnants hiding in plain sight, obscured by dust, gas, and light from other objects, or just faded away beyond our ability to see.

More Information

Max Planck Institute for Extraterrestrial Physics press release

“Hoinga: A supernova remnant discovered in the SRG/eROSITA All-Sky Survey eRASS1,” W. Becker et al., to be published in Astronomy & Astrophysics (preprint on arxiv.org)