Type I Supernovae Eric LeJeune. Supernova High-mass star’s final brilliance Star explodes A...

Type I SupernovaeType I Supernovae

Eric LeJeune

SupernovaSupernovaHigh-mass star’s final brillianceStar explodesA turning off or sudden turn on of

nuclear fusion

ClassifyingClassifyingType I & Type II

◦Type I doesn’t have hydrogenType Ia, Ib, Ic

◦Type Ia Exploded white dwarf

◦ Type Ib & Ic Massive stars that have blown away

outer layers Doesn’t have a silicon line like type Ia

Type Ia SupernovaeType Ia Supernovae

What leads to a Ia What leads to a Ia supernova?supernova?

Single Degenerate Model Double Degenerate Model

Single Degenerate ModelSingle Degenerate ModelTwo sun-like stars in binary

systemOne goes to red giant, to white

dwarfThe other star eventually goes

red giantWhite dwarf accretesChandrasekhar limit and nuclear

fusion

The ExplosionThe Explosion

Deflagration and detonation Brighter than entire galaxies

SUPERNOVA 2005KESUPERNOVA 2005KE

Visible UV X-Ray

The AftermathThe AftermathNo leftovers, no neutron star or

black holeThe white dwarf is completely

obliterated

Type Ia RemnantsType Ia Remnants

ImplicationsImplicationsSimilar compositions, same massPractically same brightnessCan measure distancesObserved Brightness =

Luminosity 4π*Distance2

Standard candle

The Universe’s Accelerating The Universe’s Accelerating ExpansionExpansionObserve supernovaDetermine distanceResults are farther away, and

receding faster than expected in a universe expanding at a constant rate

Conclude accelerating expansion

Type Ib & Ic SupernovaeType Ib & Ic Supernovae

Core CollapseCore CollapseSuper massive star at the end of its

lifetimeStar has layers of fused chemical

elements up to ironIron does not fuse so the core can’t

generate heat.Once the core reaches the

Chandrasekhar mass, the core pressure drops and overlying material falls in.

More Core CollapseMore Core CollapseThe core collapses and material

bounces off the core, resulting in a shock wave

Neutrino pulse propels shock wave

Shock wave blows star apart

Type Ib & Ic SupernovaeType Ib & Ic SupernovaeType II supernovaeType Ib supernovae

◦ Blown off hydrogen shellType Ic supernovae

◦ Blown off hydrogen and helium shells

Visualizing Type Ib & Ic Visualizing Type Ib & Ic SupernovaeSupernovae

Type Ib (SN 2005bf) Type Ic (SN 2006jc)

ImagesImages http://apod.nasa.gov/apod/image/0506/wd_cxc_full.jpg http://chandra.harvard.edu/photo/2007/deml238/deml238

_4panel.jpg http://csp1.lco.cl/~cspuser1/PUB/PROJ/CI/c1/sn05bf.html http://

en.wikipedia.org/wiki/Image:Core_collapse_scenario.png http://imagine.gsfc.nasa.gov/Images/news/SN2005ke_labe

ls.jpg

http://ircamera.as.arizona.edu/NatSci102/images/lec22_07.gif

http://space.newscientist.com/data/images/ns/cms/dn8368/dn8368-1_579.jpg

http://upload.wikimedia.org/wikipedia/commons/2/27/Evolved_star_fusion_shells.png

http://www.eurekalert.org/multimedia/pub/web/3142_web.jpg

http://www.nso.lt/stories/img/starchild.jpg http://www.supernovae.net/sn2006/u4904s5.jpg

Works ReferencedWorks Referenced Bennett, Jeffrey, Megan Donahue, Nicholas Schneider, and Mark Voit. The Cosmic

Perspective. 3rd ed. Boston: Addison Wesley, 2004.

"Dark Energy." ChemistryDaily.com. 01 Jan 2007. 27 Nov 2007 <http://www.chemistrydaily.com/chemistry/Accelerating_universe>.

Goldhaber, Gerson and Saul Perlmutter. "A study of 42 type Ia supernovae and a resulting measurement of ΩM and ΩΛ." Physics Reports 307.1-4. 01 Dec 1998 325-331. 27 Nov 2007 <http://www.sciencedirect.com>.

Hillebrandt, Wolfgang, Hans-Thomas Janka, and Ewald Müller. "How to Blow Up a Star." Scientific American Oct. 2006: 43-49.

Leibundgut, Bruno and Jesper Sollerman. "A cosmological surprise: the universe accelerates." Europhysics News 32.4. 2001 27 Nov 2007 <http://www.eso.org/~bleibund/papers/EPN/epn.html>.

"Supernova." wikipedia.org. 27 Nov 2007. Wikimedia Foundation, Inc.. 27 Nov 2007 <http://en.wikipedia.org/wiki/Supernova>.

"Type Ia Supernova." wikipedia.org. 25 Nov 2007. Wikimedia Foundation, Inc.. 27 Nov 2007 <http://en.wikipedia.org/wiki/Type_Ia_supernova>.

Van Dyk, Schuyler D.. "ASTRONOMY: Elusive Supernova Progenitors." Science 302.5648. 14 Nov 2003 1161-1162. 27 Nov 2007 <http://www.sciencemag.org/cgi/content/full/302/5648/1161>.

Wawrzyn, Alexander. "Modeling Supernovae with PHOENIX." www.hs.uni-hamburg.de. 05 Sep 2006. Universität Hamburg. 27 Nov 2007 <http://www.hs.uni-hamburg.de/EN/For/ThA/phoenix/supernova.html>.

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