by Sarah Scoles
Rejoice and be glad! Astronomers have found and characterized a relatively young supernova. It looks like this:
This supernova remnant is (perhaps, about, approximately) 2500 years old, meaning that 2500 years ago (plus however long it took the light to get here) a star exploded. The material from that explosion has been traveling outward ever since, creating the still-moving shell pictured above. It's still moving to the tune of 670 kilometers per second, or about 1.5 million miles per hour. If you were traveling that fast, you could get to the Sun in 2.5 days, and you could also have an brain hemorrhage. And just think--this stellar material has been going that fast or faster 2500 years.
Using X-ray data from NASA's Swift telescope, the researchers also found spectral evidence of Silicon, Sulphur, and Argon. With more data about which atoms are hanging out in this violent gas cloud, they will be able to tell what type of supernova this was--Type Ia or core-collapse? In the former, a white dwarf in a binary system acquires a little more of its companion's mass than it can handle; in the latter, a dying red giant star whose empty-fuel-tank fusion no longer counterbalances its gravity.
The abundances of elements like oxygen, neon, and silicon would be different in a white dwarf than they would be in a dying red giant star, so the remnants of their explosions would also differ in composition. Currently, it looks like Type Ia is going to be the winner, but, as usual, the scientists need more data.
Here's the thing: fascinating as all of that is, it's really just about one supernova remnant, and how important can one supernova remnant be in the scheme of, you know, things? How important is it that this particular supernova has gas traveling at a particular speed?
Well, it's not particularly important. What this remnant can tell us about how remnants and supernovae themselves work is important. What we can deduce about how this supernova affected its surrounding area (which depends on how supernovae work) is important. It can help explain how these explosions enable star formation and heavy-element infusion. Which is what allows you both to exist and to wear gold chains around your neck.
And the existence of this supernova, though not necessarily its details, is important because it represents a tiny step toward rectifying the discrepancy between how often we think stars in the Milky Way go supernova and how many actual remnants we see. There "should" be about 1,000 supernova leftovers in our galaxy. We know of 309. About 60 stars should" have gone supernova in the past 2,000 years. We know of 20.
This supernova makes 310 total. Cha-ching.
So do we not understand stellar evolution? Do we not understand intragalaxy interactions? Do we not understand our own home? (hahaha, of course we don't). Or have we just not found these supernova remnants because astronomy needs more funding and more and bigger telescopes in order to be able to see superfaint radiation? Only by continuing to search for -- and either find or not find -- fast, hot gas shells can we tell the difference between telescopic inadequacy and our own mispredictions.
Mark Reynolds, Shyeh Loi, Tara Murphy, Jon Miller, Dipankar Maitra, Kayhan Gultekin, Neil Gehrels, Jamie Kennea, Michael Siegel, Jonathan Gelbord, Paul Kuin, Vanessa Moss, Sarah Reeves, William Robbins, Bryan Gaensler, Rubens Reis, & Robert Petre (2013). G306.3-0.9: A newly discovered young galactic supernova remnant Astrophysical Journal arXiv: 1303.3546v1