Quiz 3 Flashcards
Where are stars born?
Stellar clusters
Many stars are found in what? Most stars found here are what?
Many stars are found in MULTIPLE STAR SYSTEMS and most are BINARIES
What kind of stellar clusters are young and which are old?
Open clusters= young
globular clusters= old
What is the significance of the mass of a star?
Mass will determine the evolutionary path of a star.
Which stars live longer? Very massive stars or less massive?
Very massive stars= a few million years
Less massive stars= tens of billions of years
What is a hydrostatic equilibrium?
main sequence stars are in this. Pressure produced by nuclear fusion balances gravity
Describe the process of the main sequence stars
When helium starts to accumulate in the core and energy production decreases, the core contracts.
Hydrogen starts to burn in the upper shell and produces energy
Star leaves the main sequence in order to achieve equilibrium
Star has to cool down, it expands and becomes a red giant
What happens after the red giant phase?
Stars, like our sun, will accumulate carbon in the core but not enough to produce energy.
They will eject outer layers and become a planetary nebula with a white dwarf in the middle.
Stars more massive than the sun will go through “multiple shell burning” (onion layers)
What produces a supernova?
When stellar core is made of iron, it is not able to produce energy and core collapses
Explain the difference between a type 1 and a type 2 supernovae
Type 1 occurs in binary systems when mass from one of the stars falls into the white dwarf, reigniting nuclear fusion and later causing explosion.
Type 2- when massive stars (iron core> 1.4 solar masses) explode
What happens after a supernova explosion?
Massive stars can become neutron or black holes.
The most massive ones (iron core > 3 solar masses) will become black holes
What are pulsars?
Rotating neutron stars are known as pulsars. They are made of neutrons, are very compact, have strong magnetic field, and spin very fast (reminding us of a light house)
What is the evolutionary path of the sun?
Main sequence
Red giant
Planetary nebula
White dwarf
The sun will NOT explode as supernova
Since no electromagnetic radiation can escape from a black hole, how can we detect such things?
Using x-Ray satellites we can detect radiation leaving the disk around the black hole
Describe black holes
The are singularities, they have no surface.
