“Do you see the absurdity of what I am? I can’t even express these things properly because I have to – I have to conceptualize complex ideas in this stupid limiting spoken language! But I know I want to reach out with s...
“Do you see the absurdity of what I am? I can’t even express these things properly because I have to – I have to conceptualize complex ideas in this stupid limiting spoken language! But I know I want to reach out with something other than these prehensile paws! And feel the wind of a supernova flowing over me!” -Ronald Moore
Well, you probably don’t actually want to feel the wind of a supernova flowing over you; trust me on this.
Image credit: ESO / L. Calçada, of the remnant of SN 1987a.
But to find one for yourself, that’s definitely within your reach, if you know where to look.
Supernovae come in a few distinct types, two of which are far more common than others.
Image credit: STSCI, NASA; NASA/T. Strohmayer (GSFC)/D. Berry (Chandra).
There are Type Ia supernovae, the most common type of supernova in our own galaxy. These occur when a white dwarf star — either from mass siphoning, accretion, or mergers — reaches above a certain mass threshold. When this occurs, the atoms at the center of the stellar corpse can no longer remain stable, and a runaway nuclear explosion occurs. The result — as we’ve seen relatively recently in our galaxy — is a fantastic supernova explosion that destroys the previously existing star!
Image credit: NASA/ESA/JHU/R.Sankrit & W.Blair.
But these types of supernovae — the Type Ia — can occur anywhere where white dwarf stars are located. Given that these are the second most common stellar-type object (behind red dwarf stars) in the Universe, at least for the next few hundred billion years (after which they’ll eventually overtake red dwarfs), predicting where the next one will occur is a herculean task, well beyond what we know how to do.
But there is another type.
Image credit: Anglo-Australian Observatory, via Pete Challis.
When ultra-massive stars, or stars at least about eight times as massive as the Sun, exhaust the last of their nuclear fuel, the core of that star begins to collapse. Normally — and this happens in stars like the Sun — the forces between particles in the central region of the star are too strong for even gravity to overcome. This is true for nearly all classes of main-sequence star; our Sun is a run-of-the-mill G-class star.
Image credit: wikimedia commons user LucasVB.
But some stars are so massive — all of the main-sequence O-stars and the brightest of the B-stars — that the Pauli Exclusion Principle is insufficient to prevent core collapse, and this leads to a runaway reaction.
In the center of these stars, the core does in fact collapse, producing either a neutron star or black hole at the center, while the outer layers of the star are destroyed in a fantastic Type II supernova explosion!
The thing is, stars like this are very, very rare; less than 0.1% of all stars are massive enough for this to happen. Furthermore, stars that are this massive live for such short amounts of time before burning through all of their fuel.
But this is great, because it tells us something: if you want to find one of these Type II supernovae, you’re way more likely to get one if you look at a young, star-forming region of space!
Image credit: NASA,ESA, M. Robberto (STScI/ESA), HST Orion Treasury Project Team.
We have a few of these star forming regions in our own galaxy, of course, perhaps the most famous of which is the Great Orion Nebula, prominently visible during the winter months.
But you don’t mine for gold in a tiny vein when there are giant ones to go after, and you don’t look for supernovae in HII-regions of relatively quiet galaxies when there are places in space so active that the entire galaxy in question is a star-forming region!
Image credit: NASA / JPL-Caltech / STScI / CXC / UofA / ESA / AURA / JHU.
The easiest way to get a galaxy that forms stars this rapidly is when two relatively equal-sized galaxies merge. The gravitational interaction causes large amoun