Looks rather long-lived for a supernova but


The bright red dot in this image is not present in 2016 images, and has been growing in brightness since late 2017 - what is it likely to be?

In which survey is it not present in 2016? I see it’s present in old SDSS and both DECaLS DR5 and DR7 images.

What makes you think it is varying in brightness? Eyeballing between different surveys?

If you look at the individual cutouts, you will see the brightness is varying.

Screenshot 2019-01-20 at 17.41.32.png
Screenshot 2019-01-20 at 17.41.49.png

Aaaah, that IS odd, thanks for the clarification.

But it not something new like a transient since it’s also visible in SDSS;


Strongly Variable star then? Or recurrent nova (SN imposter)? Nothing in SIMBAD.

Anyone else knows?

It’s present in the z-band images (= red in these RGB images), somewhat present in r-band (= green), and absent in g-band (= blue).


That would perhaps explain why it is so red, then! Any idea what it is?

Not sure, possibly a cool star?