Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Standard solar model wikipedia , lookup
Astrophysical X-ray source wikipedia , lookup
Cosmic distance ladder wikipedia , lookup
White dwarf wikipedia , lookup
Nucleosynthesis wikipedia , lookup
First observation of gravitational waves wikipedia , lookup
Planetary nebula wikipedia , lookup
Hayashi track wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Main sequence wikipedia , lookup
15-3 The Lives of Stars Studying the Lives of Stars • Astronomers must study stars at different stages to study the lives of stars A star is born Stars are born in nebula (a vast cloud of gas and dust) 2. Gravity pulls gas together 3. When nuclear fusion takes place a star is born 4. The youngest stars are called protostars 1. Lifetimes of Stars • How long a star lives depends on it’s mass • The more mass a star has the shorter it will live Red Giant Stars • As the mass of a star’s core decreases, so does its gravity • The core is no longer able to maintain the stars small size, so it expands into a red giant. Deaths of Stars • When a star runs out of fuel it turns into a white dwarf, a neutron star, or a black hole. • White dwarfs • The core of a red giant star whose outer layers have dissipated (spreads out) • Size of earth, with same mass as our sun • Turns into a black dwarf when fuel runs out • Neutron Stars • Left over from a supernova • Supernovas are giant explosions from dying stars • Left over core is called a Neutron Star • 20km across •three times the mass of our sun Death of Stars Continued • Black Holes • Leftover from a supernova of a very massive star • 5 times the mass of the sun packed into a sphere the size of a marble • Gravity so strong nothing, not even light, can escape • Quasars are black holes millions of light years away that shine very bright (galaxies with black holes in the center)