chapter 7 Flashcards
a system of planets and other smaller objects in orbit around a star
planetary system
- first plausible theory of the formation of the solar system by Immanuel Kant in 1755
- stated that the solar system formed from the collapse of an interstellar cloud of rotating gas
nebular hypothesis (2)
- a cloud of interstellar gas & dust illuminated by stars or seen in a silhouette against a brighter background
- if the outward force is less than self-gravity, the object contracts; if it is greater than self-gravity, the object expands
nebula (2)
a young stellar object that derives its luminosity from converting gravitational energy into thermal energy
protostar
the remains of the accretion disk around a young star from which a planetary system may form
protoplanetary disk
- a conserved property whose value depends on the velocity and distribution of the system’s mass in a rotating/revolving system
- L = m x v x r
angular momentum (2)
- mass
- rate of speed
- how the mass is distributed
3 aspects of angular momentum (3)
physical law that states the amount of angular momentum of an isolated system doesn’t change
conservation of angular momentum
a flat, rotating disk of gas & dust surrounding young stellar objects
accretion disk
- a primitive body of rock and ice that combines with others to form a planet
- particles that are ~1km in size
planetesimals (2)
- the stored energy in an object that is due solely to its position within a gravitational field
- material in the inner disk falls farther and picks up greater speed & higher temperature
- material in the outer disk moves slower
gravitational potential energy (3)
material that remains solid at high temperatures
refractory materials
material that remains gaseous/liquid at cooler temperatures (water, ice)
volatile materials
contains element carbon-hydrogen bonds
organic
behavior in complex systems in which a small change in the initial state of a system can lead to a large change in the final state of the system
chaotic
the theory that planets can move to a location away from where it was formed through gravitational interactions or loss of orbital energy
planet migration
atmosphere composed of mostly hydrogen & helium that forms at the same time of the planet
primary atmosphere
atmosphere that forms sometime after the host planet has formed
secondary atmosphere
- within 5 AU of the Sun
- earth-like planets made of rock & metal with a solid surface
- formed from pieces of debris in the protoplanetary disk
terrestrial planets (3)
- large amounts of surrounding hydrogen & helium gas are gravitationally captured onto a massive rocky core
- process for giant gas planets
- gravitational energy is converted into thermal energy as individual atoms & molecules moved faster
core accretion gas capture (3)
a primitive planetesimal composed of ices and refractory materials that has survived planetary accretion
comet nuclei
a planet orbiting a star other than the Sun with a mass less than 10-12 Jupiter masses
exoplanet
- a “failed star” without enough mass to fuse hydrogen
- more massive than Jupiter, but less massive than 0.08 solar masses
brown dwarfs (2)
a method of detecting extrasolar planets by measuring the decrease in light from a star as its orbiting planet passed in front of the star as viewed from Earth
transit method
- motion detected by doppler shift
- only works on giant planets
- determines a planet’s orbit
radial velocity method (3)
the bending of light by gravity
gravitational lensing
a large, jupiter-like exoplanet located very close to its parent star
hot jupiters
an exoplanet with ~ 2-10 times the mass of earth
super earths
an exoplanet that orbits around 2 stars
circumbinary planets
