In today’s installation of how stars harm one another, we have the tale of the star that was left behind when its companion exploded. Back in 2013, a supernova went off in the nearby galaxy NGC 3287. The initial burst saturated the scene, but as the light of the supernova faded, a small source of ultraviolet became visible, and that small glow appears to be a companion star.
This particular supernova wasn’t rich in hydrogen, and it had previously been assumed that the original star had blown away its hydrogen gas atmosphere. If this was the case, over time, light from the supernova would allow us to see that cloud of hydrogen, but that didn’t happen. Now, researchers are looking at this companion and thinking it just might be the hydrogen thief. And thinking that this kind of gassy robbery may be happening on a regular basis throughout our universe.
According to researcher Maria Drout: In recent years many different lines of evidence have told us that stripped supernovae are likely formed in binaries, but we had yet to actually see the companion. So much of studying cosmic explosions is like forensic science—searching for clues and seeing what theories match. Thanks to Hubble, we are able to see this directly.
Today, this system consists of either a neutron star or black hole that was left behind by the supernova and this bright ultraviolet companion, which is also a massive star and which will also one day explode… maybe. The exact future of this system is tied to the distance between that surviving star and the remnant of the supernova. Too close? They merge. Too far? Meh, they fly apart.
That coming together is what we want to see. As researcher Ori Fox explains: With the surviving companion of SN 2013ge, we could potentially be seeing the prequel to a gravitational wave event.
Yes, folks, if these stellar remnants merge, it will literally expand and contract our world in a detectable gravitational wave. Fox does add: Such an event would still be about a billion years in the future.
Folks, there is no reason to stay up waiting for this merger, but it is cool to know we are seeing the start of the kind of event LIGO is letting us catch at the end. Now, we just need to find a way not to skip over the middle.
Hubblesite press release
“The Candidate Progenitor Companion Star of the Type Ib/c SN 2013ge,” Ori D. Fox et al., 2022 April 13, The Astrophysical Journal Letters