Stellar Evolution

Stars can take different evolutionary paths due to their initial:

• Brightness

• Mass

• Temperature

• Color

Helium flash occurs:

• In very massive stars

• When the helium nucleus breaks its degeneracy

• At the Asymptotic Giant Branch phase

• when the nucleus burns helium

Which following states regarding the main sequence is wrong?

• Main sequence undergo fusion hydrogen within their cores.

• Mass is the key factor to determine the lifespan of the star

• The energy is transported via radiation or convection

• Hydrogen burns in a shell

Which following evolutionary sequence is correct?

• PMS-AGB-RGB-BH

• MS-HB-RGB-AGB-SN-WD

• MS-RGB-HB-AGB-PN-WD

• MS-RGB-HB-AGB-SN-WD

When a red giant's outer atmosphere drifts away, it becomes:

• Expanding nebula

• Planetary nebula

• White dwarf cloud

• Planetary cloud

Why will a low/medium mass star will never create a Black Hole

• Collapse is too slow

• Collapse is too fast

• Electron degeneracy

• Proton degeneracy

Stars like the Sun probably do not form iron cores during their evolution because

• All the iron is ejected when they become planetary nebulas.

• Their cores never get hot enough.

• Their strong magnetic fields keep their iron in their atmospheres.

• The iron converted in heavier elements through proton capture

At the RGB stellar evolution phase the stars have a degenerate core and fuse helium in a shell

• True

• False

There are evidences that at the center of galaxies live:

• Super massive black hole

• Stellar black hole

• Cosmic black hole

• Compact star

At the late stage of a low mass star evolution the outer layers escape into space, leaving behind a:

• White dwarf

• Neutron star

• Red giant

• Supernova