This is an update to my May 16 post. The sky was clear and moonless last Friday night, so I was able to check back in on the M61 supernova. A month later, it has faded only a little bit. I’m happy to report that the “seeing” was better this night, so this image shows somewhat more detail in the galaxy compared to my earlier images.
Move your mouse over the image to display some notes. I’ve pointed out two other smaller spiral galaxies. The four arrows lacking legends point to foreground stars in our Milky Way that just happen to be in nearly the same direction and have nearly the same brightness as the supernova that is part of the M61 galaxy.
M61 Supernova on June 12
Here was M61 on May 15 a week after the supernova appeared
Here was M61 on April 15, before the supernova exploded
M61 itself is a beautiful barred spiral located about 52 million light-years away with a pinwheel of nebula-flecked arms and a bright, non-stellar core. It’s also a starburst galaxy with an exceptionally high rate of star formation. Short-lived supergiant stars hatched within its myriad nebulae provide the fodder for regular supernovae. We’ve been enjoying the fireworks since the first supernova blew up here in 1926. Seven more followed in 1961, 1964, 1999, 2006, 2008, 2014 and now in 2020. M61 is similar in size to our own Milky Way galaxy.
A supernova is a powerful and luminous stellar explosion. This transient astronomical event occurs during the last evolutionary stages of a massive star or when a white dwarf is triggered into runaway nuclear fusion. The original object, called the progenitor, either collapses to a neutron star or black hole, or it is completely destroyed. The peak optical luminosity of a supernova can be comparable to that of an entire galaxy, before fading over several weeks or months.
The most recent directly observed supernova in the Milky Way was Kepler’s Supernova in 1604. Observations of supernovae in other galaxies suggest they occur in the Milky Way on average about three times every century.