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 Distant Type 1A Supernova vs, Universe Age
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lrjarhead
 Thursday, February 02 2012 @ 09:08 pm EST (Read 1427 times)  
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At the annual meeting of the American Astronomical Society in Austin, TX, January 11, a group of scientists revealed data on the fartherest Type 1A supernova yet detected. The object, designated informally as "SN Primo", calculated out to a distance of 9 billion light years!

Now a Type 1A supernova is a white dwarf existing in close proximity to another stellar object(s?) so that it can receive mass from the star that is in close proximity - until it reaches 1.4 solar masses (Chandrasekhar Limit), at which time it detonates with a thermonuclear explosion which causes it to shine briefly brighter than anything in the host galaxy, even the galaxy itself . The properties of this type supernova are thought to be fairly well understood - mass is always 1.4 s.m. so that mass/luminosity relationship is easily determined and the light curves of type 1A's is well documented. Spectrographic analysis is the final determiner, no signs of Hydrogen is the primary identifier and others.

Here's my comment - it takes a 1 solar mass star (like our sun) 10 billion years to reach the white dwarf stage (once there the white dwarf can exist in that stage for billions of years before consuming all its' Helium). So now we have a white dwarf that has existed for at least 10 billion years and has exploded and then it has taken the light from that event another 9 billion years to reach our photon detectors - that's 19 billion years - pretty good for a universe that's 13.7 billion years old!

Mike

p/s a great read on Type 1A's is Kershners' "Extravegant Universe"


 
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lrjarhead
 Saturday, February 04 2012 @ 03:28 pm EST  
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More on White Dwarfs as Type 1A SN's - While a 1.0 solar mass star of average composition takes about 10 billion years to reach the white dwarf stage (this type mass accounts for about 80% of all white dwarfs); a 1.25 mass star takes 4.6 billion years to reach this stage, a 1.5 mass star reaches this stage in only 2.3 billion years and a 2.25 solar mass star in 585 million years! So my comment is without merit I think because it obvious that with a little more mass, in a binary system, events like "SN Primo" can take place within current time lines for age of the universe estimates. Note: White Dwarfs can be formed from stars that had a mass greater than the Chandrasekhar limit during their main sequence phase, but must be below it prior to the white dwarf stage (and this is probably accomplished by ejecting mass during the Red Giant phase). Good reference: Stars and Clusters by Cecilia Payne-Gaposchkin, Harvard University Press, 1979. Thanks to Adam Reiss for giving me the hint.


 
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Pablo Rosell
 Sunday, February 05 2012 @ 05:09 pm EST  
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Thank you for sharing Mike!
Although there must had been a flaw in your argument (assuming 1 solar mass) it made my day! Such paradoxes and/or contradictions with a conclusion the way you wrote it are truly amusing Wink


Pablo - Fayetteville, AR
 
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