Type II-P Supernovae as a New Standard Candle

Posted by StarryGift On Mar 20, 2009

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Sunday, September 12, 2010

Type II-P Supernovae as a New Standard Candle

id="attachment_1009" class="wp-caption alignleft" style="width: 568px">href="http://www.universetoday.com/wp-content/uploads/2006/12/2006-1130supernova.jpg">class="size-full wp-image-1009 " src="http://www.universetoday.com/wp-content/uploads/2006/12/2006-1130supernova.jpg" alt="" width="558" height="384" />class="wp-caption-text">Artist illustration of a supernova. Image credit: ESO

Much of astronomical knowledge is built on the cosmic distance ladder. This ladder is built to determine distances to objects in our sky. Low lying rungs for nearby objects are used to calibrate the methodology for more distant objects which are, in turn, used to calibrate for more distant objects and so on. One of the reason so many runs need to be added is that techniques often become difficult to impossible to used past a certain distance. href="http://www.universetoday.com/40468/cepheid-variables/" class="alinks_links" title="" rel="external">Cepheid Variables are a fantastic object to allow us to measure distances, but their href="http://www.universetoday.com/35378/luminosity/" class="alinks_links" title="" rel="external">luminosity is only sufficient to allow us to detect them to a few tens of millions of href="http://www.universetoday.com/42863/parsecs/" class="alinks_links" title="" rel="external">parsecs. As such, new techniques, based on brighter objects must be developed.

The most famous of these is the use of Type Ia href="http://www.universetoday.com/52416/supernovae/" class="alinks_links" title="" rel="external">Supernovae (ones that collapse just pass the href="http://www.universetoday.com/40852/chandrasekhar-limit/" class="alinks_links" title="" rel="external">Chandrasekhar limit) as "href="http://www.universetoday.com/31044/cosmologists-improve-on-standard-candles-measurement/" class="alinks_links" title="" rel="external">standard candles". This class of objects has a well defined standard luminosity and by comparing it's apparent brightness to the actual brightness, astronomers can determine distance via the href="http://en.wikipedia.org/wiki/Distance_modulus">distance modulus. But this relies on the fortuitous circumstance of having such an event occur when you want to know the distance! Obviously, astronomers need some other tricks up their sleeve for cosmological distances, and a new study discusses the possibility of using another type of href="http://www.universetoday.com/46644/supernova/" class="alinks_links" title="" rel="external">supernova (SN II-P) as another form of standard candles.(...)
Read the rest of href="http://www.universetoday.com/73365/type-ii-p-supernovae-as-a-new-standard-candle/">Type II-P Supernovae as a New Standard Candle (437 words)

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