Chapter 5 (post midterm 1) Flashcards
Gravitational equilibrium
energy supplied by fusion maintains the pressure that balances the inward crush of gravity
i.e. the matter above create pressure inwards, thus equal force (by thermonuclear reactions) goes outwards
Electrical forces
protons have the same charge so they repel each other
strong force
protons and neutrons stick together when very close like velcro
nuclear fission
big nucleus splits into smaller pieces
electrical forces win over the strong force
nuclear Fusion
small nuclei stick together to make a bigger one
strong force wins over the electrical forces
Helium fusion
with enough pressure and heat, helium will fuse to carbon
Planetary nebula and star relation
the center of the nebula, the contracted core of the former red giant which is about the size of the art
that core is hot and dense - a white dwarf
overdensity
a cloud of gas in space causes a piece to collaps from gravity
when do cloud collapses happen
when gravity overcomes pressure
angular momentum =?
ang mom = mass * radius * velocity
nebular theory slide
dense material close to star
51 peg b, first exoplanet orbiting a sun-like star
min mass of 0.472
orb period: 4.2 days
semi major axis of 0.0534 AU
delta for Amt of light being blocked by a planet
it’s the ratios of the areas
transit prob equation
Radius of start / semi major axis of that orbit
Rs/a
Orbital period
transfer happens over and over again
radius of the planet
from transit depth delta (assuming radius of the star)
semi-major axis
from keeper’s 3rd law (assuming the mass of the star, and the mass of the planet is negligible)
orbital inclination
from the ratio of ingress time to duration
waves in space time
just like accelerating charges cause electro-magnetic waves, accelerating mass causes waves in space time
habitable zone
orbital distances where liquid water could persist on the planet’s surface
Energy balance
energy incident on a planet equals energy emitted by the planet
needs to stay in equilibrium (works in seconds)
