Stellar Explosion has Stellar Explosion has Many Layers Many Layers

Department of PhysicsDepartment of PhysicsNational Tsing Hua UniversityNational Tsing Hua University

G.T. ChenG.T. Chen2006/11/062006/11/06

Oct. 26 , 2006Oct. 26 , 2006

http://www.universetoday.comhttp://www.universetoday.com

Cassiopeia ACassiopeia A

R.A. :23h 23m 26.7s R.A. :23h 23m 26.7s Dec. :+58º 49' 03.00" Dec. :+58º 49' 03.00" Distance : ~11000 light yearsDistance : ~11000 light years It is known as a supernova remnantIt is known as a supernova remnant

SNR 111.7-2.1 SNR 111.7-2.1 Apparent Dimension : 5 arc minApparent Dimension : 5 arc min

~ 10 light years~ 10 light years

Cassiopeia ACassiopeia A

It is the youngest known supernova remnant iIt is the youngest known supernova remnant in our Milky Way, and the strongest extrasolar rn our Milky Way, and the strongest extrasolar radio source in the sky. adio source in the sky.

Calculating its expansion back, astronomers hCalculating its expansion back, astronomers have found that the supernova must have blowave found that the supernova must have blown up around 1667n up around 1667

The original star is about 15 to 20 times solar The original star is about 15 to 20 times solar mass and was made up of concentric shells of mass and was made up of concentric shells of elementselements

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From Spitzer’s observations, They have founFrom Spitzer’s observations, They have found new bits of the ‘onion’ layers that had not d new bits of the ‘onion’ layers that had not been seen beforebeen seen before

This tells us that the star’s explosion was not This tells us that the star’s explosion was not chaotic enoughchaotic enough

It’s possible that the star exploded in a uniforIt’s possible that the star exploded in a uniform fashion, blowing its layers out in successive m fashion, blowing its layers out in successive order. Then those layers should be preserved iorder. Then those layers should be preserved in the expanding debrisn the expanding debris

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Spitzer’s infrared detectors were able to Spitzer’s infrared detectors were able to observed gases and dusts consisting of thobserved gases and dusts consisting of the middle-layer elements neon, oxygen ane middle-layer elements neon, oxygen and aluminumd aluminum

It seems that most of the star’s original lIt seems that most of the star’s original layers flew outward in successive order, bayers flew outward in successive order, but at different average speeds depending ut at different average speeds depending on where they started on where they started

This artist's concept illustrates that massive star before and after it blew up

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Cassiopeia A is the ideal target for Cassiopeia A is the ideal target for studying the anatomy of a supernova studying the anatomy of a supernova explosion explosion

ReferencesReferences

http://www.universetoday.comhttp://www.universetoday.com Oct. 26 , 2006Oct. 26 , 2006 http://http://www.spitzer.caltech.edu/spitzerwww.spitzer.caltech.edu/spitzer http://chandra.harvard.edu/photo/0237http://chandra.harvard.edu/photo/0237

>>Thank you<<>>Thank you<<

Infrared data from the Spitzer Space Infrared data from the Spitzer Space Telescope are colored red; optical Telescope are colored red; optical data from the Hubble Space data from the Hubble Space Telescope are yellow; and X-ray data Telescope are yellow; and X-ray data from the Chandra X-ray Observatory from the Chandra X-ray Observatory are green and blue are green and blue

Spitzer reveals warm dust in the Spitzer reveals warm dust in the outer shell with temperatures of outer shell with temperatures of about 10 about 10 00C , and Hubble sees the C , and Hubble sees the filamentary structures of warmer filamentary structures of warmer gases about 10,000 gases about 10,000 00C . Chandra C . Chandra shows hot gases at about 10 million shows hot gases at about 10 million 00CC

radioradioX-rayX-ray

opticaloptical

InfraredInfrared ReferenceReference