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Nachor
2007-Aug-31, 09:58 PM
For how long after the supernova event can something like the Crab nebula be detected by current technology?
What would be the time for the remains of a thermonuclear supernova?

And for how long could neutron stars created in SN events be detected?

neilzero
2007-Aug-31, 10:28 PM
I can't make a guess. Are all supernova thermonuclear? Up to about 10,000 light years, neutron stars are detectable for at least ten billion years. They cool very slowly. Neil

Tim Thompson
2007-Aug-31, 10:44 PM
For how long after the supernova event can something like the Crab nebula be detected by current technology?
Visibly, probably about 10,000 years, less if it is mixing with a dense surrounding medium. Frail, Goss & Whiteoak, 2004 (http://adsabs.harvard.edu/abs/1994ApJ...437..781F) derived a mean age of about 60,000 years for radio supernova remnants. So i should think that, if they are not confused by mixing in the surrounding interstellar medium, about 100,000 years is a reasonable estimate on the oldest SNR that can be observed. Radio SNR are still being pumped by emission from the central neutron star. If the SN explosion kicks the neutron star (pulsar) free from the SNR, then its observational lifetime should be much less.


What would be the time for the remains of a thermonuclear supernova?
Same question, same answer, as far as I can tell.


And for how long could neutron stars created in SN events be detected?
Lorimer, at al., 2007 (http://adsabs.harvard.edu/abs/2007MNRAS.379.1217L) report pulsar ages in the few hundred million year range, which seems to be easy to do. Lohmer, et al., 2004 (http://adsabs.harvard.edu/abs/2004A%26A...426..631L) give the pulsar in the PSR J2145-0750 binary system a "characteristic age" of 10.4 billion years. So it looks like the neutron stars are visible for billions of years at least.

antoniseb
2007-Aug-31, 11:11 PM
neutron stars are detectable for at least ten billion years. They cool very slowly. Neil

Hmmm. The might be detectable that long if they have a companion, but Geminga and the other isolated neutron stars we've discovered are all nearby, and all less than about one million years old, and fading fast.

trinitree88
2007-Aug-31, 11:27 PM
For how long after the supernova event can something like the Crab nebula be detected by current technology?
What would be the time for the remains of a thermonuclear supernova?

And for how long could neutron stars created in SN events be detected?

Nachor. Somewhere in the annals of physics articles is one that states that an average galaxy has from 1,000-10,000 neutron stars in it's population at a time. Although they form in the disk, they largely circulate up into the halo, and back down through the disk again in their orbits. Most are not ejected (galactic escape velocity runs ~250-400 km/sec)...but some are. We should see one coming at us from far away, but with ~ a million Earth masses, there's not much we could do about it. You probably have a better chance of being struck by a meteorite...that has happened to people. pete.:shifty:

see;http://antwrp.gsfc.nasa.gov/diamond_jubilee/papers/lamb/node4.html

Nachor
2007-Sep-01, 07:31 PM
Many thanks to all of you. :)