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Fraser
2005-Jun-08, 05:00 PM
SUMMARY: Stars - like people - are born, grow, mature, and die. But out of stellar death comes new life, as matter freshly minted within such stars flies outward to join gases previously boiled off during its hey day. Based on extended Chandra observations of the oldest supernova discovered using X-ray technologies (SN 1970G), astronomers think we might be watching a star in the transition phase between its old life as a giant blue star that went supernova, and its new life as a supernova remnant.

View full article (http://www.universetoday.com/am/publish/afterlife_supernova.html)

What do you think about this story? Post your comments below.

antoniseb
2005-Jun-08, 05:18 PM
This is a nice story. It will be interesting to see the comparisons between this supernova and SN1987a, which was also a nearby Type II, but possibly a black hole progenitor, as opposed to a neutron star progenitor as SN1970G seems to be.

Greg
2005-Jun-08, 06:03 PM
This a timely article to add. This SN is 17 years further along than the 1987a and still there is no sign of the core remmenant. If the current model regarding neutron star formation is correct, it is unlikely that we will see one in our lifetimes.

om@umr.edu
2005-Jun-08, 06:26 PM
It is great to see recognition that stellar evolution does not cease with a supernova.

Evidence to support one part of this story is much closer than most realize, "out of stellar death comes new life".

With kind regards,

Oliver

http://www.umr.edu/~om

The Near-Sighted Astronomer
2005-Jun-08, 06:39 PM
Before reading Stefan and Kip's paper I really had no concept of how a supernova remnant finally took form. Meanwhile i had had this baseless concept that remnants such as the Cygnus Loop radiated due to excitation from nearby stars. In fact its now clear to me that there is so much energy in the ejected material that it alone accounts for the irredescence of an SNR. Now with Summer nearly upon us i will be able to gaze on the Veil nebula in Cygnus (Cygnus Loop) with much greater appreciation.

jeff

The Near-Sighted Astronomer
2005-Jun-08, 06:41 PM
Evidence to support one part of this story is much closer than most realize, "out of stellar death comes new life".

That evidence is as near as hands and feet - we are living embodiments of some SNR that existed 5 billion years ago...

(But then Oliver you knew this - you subtle being you...)

om@umr.edu
2005-Jun-08, 11:30 PM
Originally posted by The Near-Sighted Astronomer@Jun 8 2005, 06:39 PM
In fact its now clear to me that there is so much energy in the ejected material that it alone accounts for the irredescence of an SNR.

jeff
Yes, Jeff, nuclear reactions do not cease with the SN explosion.

This has been a problem for those trying to decide if short-lived isotopes that were alive at the birth of the solar system came from the supernova itself, or from later irradiation of the supernova debris.

We know that two isotopes, Pu-244 and Fe-60, came from the supernova itself. These pinpoint when the explosion occurred.

The Al-26/Al-27 ratio was almost unity in some silicon carbide, and probably the Al-26 in these came from the supernova.

Many short-lived isotopes may been made in the supernova, and continued to be produced after the explosion. Those complicate the record and make it difficult to decipher.

With kind regards,

Oliver
http://www.umr.edu/~om

The Near-Sighted Astronomer
2005-Jun-09, 12:02 AM
Again Oliver thanks - so it is not the kinetic energy stored up in the ejecta but radioactivity that powers the luminescence seen in SNRs. - Is this correct?

om@umr.edu
2005-Jun-09, 04:14 AM
Originally posted by The Near-Sighted Astronomer@Jun 9 2005, 12:02 AM
Again Oliver thanks - so it is not the kinetic energy stored up in the ejecta but radioactivity that powers the luminescence seen in SNRs. - Is this correct?
Yes, basically that seems to be right.

In fact decay of "doubly-magic"* nuclei, like Ni-56, produced abundantly near the supernova core, has been detected in young SNR's like that produced by SN1987A.

This is the source for the Fe-56 that constitutes >90% of all the iron atoms beneath our feet.

Ni-56 -(7 day)-> Co-56 -(77 day)-> Fe-56

With kind regards,

Oliver
http://www.umr.edu/~om

*Like atomic electrons in the noble gases, neutrons and protons in the nucleus have unusual stability at certain closed "shells". As 18 and 36 are closed shells of atomic electrons for noble gases Argon and Krypton, likewise 20 and 28 are closed shells of neutrons or protons. Ni-56 is called "doubly-magic" because it consists of 28 protons and 28 neutrons.

antoniseb
2005-Jun-09, 12:43 PM
Originally posted by om@umr.edu+Jun 9 2005, 04:14 AM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (om@umr.edu @ Jun 9 2005, 04:14 AM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-The Near-Sighted Astronomer@Jun 9 2005, 12:02 AM
Again Oliver thanks - so it is not the kinetic energy stored up in the ejecta but radioactivity that powers the luminescence seen in SNRs. - Is this correct?
Yes, basically that seems to be right.
[/b][/quote]
You might want to qualify that statement to reflect where and when the luminescence is observed. Yes, evidence of decaying Ni56 is seen in SNs, but there is no way that this is an important source of energy in SN Remnants 30 to 30,000 years after the explosion. (77 day half-life on the Cobalt).

The light from these depends on where you look, either kinetic energy from the cloud advancing through the ISM (such as the red tendrils in the Crab nebula), or ionization from the sweeping magnetic field of the neutron star (such as the blue haze in the middle of the Crab nebula).

om@umr.edu
2005-Jun-10, 06:47 PM
You are right, Anton.

I tried to clarify this in a comment posted in today&#39;s discussion of Spitzer&#39;s Post-Mortum View of A Star (http://www.universetoday.com/forum/index.php?showtopic=7743)

With kind regards,

Oliver
http://www.umr.edu/~om