08 - star deaths, binary systems, and compact objects Flashcards
star with least mass, pressure-temperature thermostat is slow, and it consumes H slowly and last 100 billion years more or more, completely convective
red dwarf
less than about 4 solar masses, not hot enough to ignite carbon
low-mass (sunlike) star
a dying star when fusion in core is failing because of build-up of carbon and oxygen. (the radius changes, it puffs up, and its less dense)
Eventually becomes a white dwarf
red giant
fusion reacts in the core, cool, post main-sequence “alive” star, helium core fusion found in the horizontal branch
Yellow giant
dead star - expanding shell(s) of gas ejected from low-mass dying star in red giant stage, slow winds and jets
Planetary nebula
central star remnant contracts to dense core (in the planetary nebula)
ARE HOT and LOW luminosity,
bottom left hand side of the graph
white dwarf
(the core that’s leftover after the star dies)
extremely high-density matter, pressure no longer depend on temperature (super packed electrons, and now it isn’t normal matter)
Degenerate matter
greater than 1.4M (white dwarf is smaller than this) which will collapse and NOT support.
Chandrasekhar-Landau limit
tell me about where the red dwarf is alive 90% of its lifetime, what happens at its final stage, and the process it takes
90% of its lifetime: main sequence (H - HE)
final stage: shrink, cool (we’ve actually never seen a red dwarf die)
process: fusion ends
tell me about where the sun-like G star is alive 90% of its lifetime, what happens at its final stage, and the process it takes
90% of its lifetime: main sequence (fuse H-HE)
final stage: red giant, yellow giant, red giant, no fusion
process: He shell, HE fusion, C/O ash
displacement/time change
speed (s)
direction distance change/ time change
velocity (v)
velocity change/time change
acceleration (a)
two+ stars can orbit at at a great distance or as close as 0.1AU
binary system
volume of space a star sweeps gravitationally in a binary system
roche lobe
