* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download PowerPoint File
Spitzer Space Telescope wikipedia , lookup
Cassiopeia (constellation) wikipedia , lookup
Nebular hypothesis wikipedia , lookup
Star of Bethlehem wikipedia , lookup
Theoretical astronomy wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Stellar classification wikipedia , lookup
Planetary habitability wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Dyson sphere wikipedia , lookup
Perseus (constellation) wikipedia , lookup
Future of an expanding universe wikipedia , lookup
H II region wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Corvus (constellation) wikipedia , lookup
Stellar kinematics wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Stellar Evolution In post-Main-Sequence evolution, what you see on the surface is not a good indicator of what is happening deep in the interior Core contraction occurs, core smaller and hotter. Star “ascends the Giant Branch” Question: Why don’t The Helium nuclei Begin to fuse? In low mass PMS stars, the “Helium Flash” occurs. Nuclear reactions involving Helium – Carbon. Also called the “Triple Alpha Process” 3He C At time of the Helium Flash, a star evolves to the right on the HR diagram, at near constant luminosity Helium Flash converts Helium core to Carbon, Oxygen Stellar evolution making chemical structure of the star more and more complicated As star evolves further, it develops a Helium-burning shell All the action is deep in the tiny core of the star As Helium shell burning stars, the star moves onto the “Asymptotic Giant Branch” The Helium shell-burning is unstable and sends thermal pulses through the star, throwing off the outer layers of the star into space. As the outer layers are peeled back, it reveals the extremely hot, ultraviolet-emitting carbon and oxygen core which ionizes the stellar wind Hot core photoionizes the surrounding stellar wind or ejecta. Resulting object is a Planetary Nebula, like M57 An incredible yarn, but all the pieces are there in the night sky • • • • • • Red Giants Horizontal Branch Giants Asymptotic Giant Branch Stars Mira Variables Planetary Nebulae White Dwarf Stars