Quick introduction: Supernova !

Visible supernovae are uncommon and of great interest to astronomers.

They occur when a massive star has burned up most of its “fuel” and suddenly “collapses”. A shock wave is formed which blows off the outer layers of the star.

Supernovae in our own galaxy had not been seen since the 1600’s

until ………………………… 1987

One dramatic result of stellar evolution: a supernova remnant

Hydrostatic equilibrium maintains a star’s size during Stage 7

Stellar composition changesas the hydrogen is used up

During stage 7 of stellar evolution,

hydrogen burning causes a build-up of

helium in the star’s core.

Hydrogen shell burning occurs around an “ash” core, which is mostly helium, and the temperature is T = 10 million K

Helium shell burning continues, and carbonburning commences

Heavy Element Fusion- shells like an onion

A Type II Supernova is a “core collapse” and occurs when the core is finally pure iron, which cannot be fused to other elements. The core collapses

to a big ball of neutrons, which causes a shock wave to bounce back outward, which blows off the entire envelope

of the red giant, to form a supernova remnant.

1994

SN2005cs in M51(Whirlpool galaxy) discovered June 27, 2005

SN2005cs in M51(Whirlpool galaxy) discovered June 27, 2005

Supernovae in our galaxy have been infrequent.

• Historical supernovae in the Milky Way (none observed by telescope !!!!): http://www.seds.org/messier/more/mw_sn.html

• Recent supernovae by date: http://cfa-www.harvard.edu/iau/lists/RecentSupernovae.html

• All supernovae since 1885: http://cfa-www.harvard.edu/iau/lists/Supernovae.html

• Links for supernovae on the web: http://rsd-www.nrl.navy.mil/7212/montes/sne.html

• Latest supernovae (by current brightness !): http://www.rochesterastronomy.org/supernova.html

• Supernova SN2005cs in M51 (Whirlpool galaxy): http://www.rochesterastronomy.org/sn2005/sn2005cs.html also see: http://antwrp.gsfc.nasa.gov/apod/ap050719.html

Supernova Remnants

Vela supernova remnant

Other examples:

Cassiopeia A (link) (link) N63A (link)

Crab nebula

M1 – the Crab Nebula

is from a supernova seen in year A.D. 1054

The remnant is 1800 pc away and the diameter is currently 2 pc.

Astronomers have been waiting for hundreds of years for a bright, nearby supernova.

Finally, one night in 1987…

We learn the story of the observation in the movie

“Death of a Star” (from the Nova series on PBS)

Supernova 1987A seen near nebula 30 Doradus

Supernova Light Curves fall into two types

Supernova 1987A was not typical

Supernova 1987A

link link link link

See mpeg animations of this.

Eta Carinae will probably go supernova

in the next 100,000 years

or so.

SEDS link