4 ms·

Finding information on this appears to be kinda hard, but it looks like the best estimate for the 'kill radius' of a supernova (i.e. will cause mass extinctions

Finding information on this appears to be kinda hard, but it looks like the best estimate for the 'kill radius' of a supernova (i.e. will cause mass extinctions) is 30 light years. So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser. Eta Corina is a double star containing at least one hypergiant that's going to go supernova any epoch now, so it gets studied a lot. It's 7500 light years away and I believe it's judged not to be a threat, although there may be ozone layer damage and it's probably not healthy to be an unshielded astronaut. However supernovae appear to emit gamma ray bursts along their axes. These can travel very large distances. Eta Corina's isn't point our way, but Tabby's Star? Who knows. 1500 light years is basically point blank range for a GRB, so if one is coming our way that would be very bad news. Like, worse than mass extinction grade bad news.

jerf 10y ago
"So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser." Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less. (I have to say it "applies here" because people sometimes overapply the law. It only applies when something is spreading out in an even sphere. However, that applies to supernovae, or at least close enough.) You're right that I neglected gamma ray bursts. But it also doesn't seem like this star could be building up to that, since it requires conditions not evident there. (I'm just following up on my point, not implying that you claimed otherwise.)
- david-given 10y ago
  > Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less. Oh, bah. Yes, of course. My upbringing in Flatland is obviously showing.
  - jerf 10y ago
    Excellent riposte, good sir!
akiselev 10y ago
I believe the most powerful gamma ray bursts, the ones that are powerful enough to strip away our atmosphere at thousands of light years, are caused by superluminous supernovae (aka hypernovae) and weaker GRBs like the ones we usually see are caused by type 1c and 2b/n supernovae, although it is unclear whether they are different or closely related to hypernovae. The latter create long duration gamma ray bursts which last a lot longer than the usual burst and carry significantly more energy.

jerf 10y ago

"So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser." Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less. (I have to say it "applies here" because people sometimes overapply the law. It only applies when something is spreading out in an even sphere. However, that applies to supernovae, or at least close enough.) You're right that I neglected gamma ray bursts. But it also doesn't seem like this star could be building up to that, since it requires conditions not evident there. (I'm just following up on my point, not implying that you claimed otherwise.)

david-given 10y ago
> Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less. Oh, bah. Yes, of course. My upbringing in Flatland is obviously showing.
- jerf 10y ago
  Excellent riposte, good sir!

akiselev 10y ago

I believe the most powerful gamma ray bursts, the ones that are powerful enough to strip away our atmosphere at thousands of light years, are caused by superluminous supernovae (aka hypernovae) and weaker GRBs like the ones we usually see are caused by type 1c and 2b/n supernovae, although it is unclear whether they are different or closely related to hypernovae. The latter create long duration gamma ray bursts which last a lot longer than the usual burst and carry significantly more energy.