chapter 7

Question 1

a system of planets and other smaller objects in orbit around a star

Answer 1

planetary system

Question 2

• 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

Answer 2

nebular hypothesis (2)

Question 3

• 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

Answer 3

nebula (2)

Question 4

a young stellar object that derives its luminosity from converting gravitational energy into thermal energy

Answer 4

protostar

Question 5

the remains of the accretion disk around a young star from which a planetary system may form

Answer 5

protoplanetary disk

Question 6

• 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

Answer 6

angular momentum (2)

Question 7

• mass
• rate of speed
• how the mass is distributed

Answer 7

3 aspects of angular momentum (3)

Question 8

physical law that states the amount of angular momentum of an isolated system doesn’t change

Answer 8

conservation of angular momentum

Question 9

a flat, rotating disk of gas & dust surrounding young stellar objects

Answer 9

accretion disk

Question 10

• a primitive body of rock and ice that combines with others to form a planet
• particles that are ~1km in size

Answer 10

planetesimals (2)

Question 11

• 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

Answer 11

gravitational potential energy (3)

Question 12

material that remains solid at high temperatures

Answer 12

refractory materials

Question 13

material that remains gaseous/liquid at cooler temperatures (water, ice)

Answer 13

volatile materials

Question 14

contains element carbon-hydrogen bonds

Answer 14

organic

Question 15

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

Answer 15

chaotic

Question 16

the theory that planets can move to a location away from where it was formed through gravitational interactions or loss of orbital energy

Answer 16

planet migration

Question 17

atmosphere composed of mostly hydrogen & helium that forms at the same time of the planet

Answer 17

primary atmosphere

Question 18

atmosphere that forms sometime after the host planet has formed

Answer 18

secondary atmosphere

Question 19

• 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

Answer 19

terrestrial planets (3)

Question 20

• 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

Answer 20

core accretion gas capture (3)

Question 21

a primitive planetesimal composed of ices and refractory materials that has survived planetary accretion

Answer 21

comet nuclei

Question 22

a planet orbiting a star other than the Sun with a mass less than 10-12 Jupiter masses

Answer 22

exoplanet

Question 23

• a “failed star” without enough mass to fuse hydrogen
• more massive than Jupiter, but less massive than 0.08 solar masses

Answer 23

brown dwarfs (2)

Question 24

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

Answer 24

transit method

Question 25

• motion detected by doppler shift
• only works on giant planets
• determines a planet’s orbit

Answer 25

radial velocity method (3)

Question 26

the bending of light by gravity

Answer 26

gravitational lensing

Question 27

a large, jupiter-like exoplanet located very close to its parent star

Answer 27

hot jupiters

Question 28

an exoplanet with ~ 2-10 times the mass of earth

Answer 28

super earths

Question 29

an exoplanet that orbits around 2 stars

Answer 29

circumbinary planets