AST 1002 EXAMS TEST PAPER ANSWERS AND
QUESTIONS SET A+
✔✔During a transit event, the absorption line of the star will be... - ✔✔Not shifted at all.
✔✔The gravitational force exerted on a star by a planet is equal to that exerted on the
planet by the star and in the opposite direction is... - ✔✔equal to that exerted on the
planet by the star and in the opposite direction
✔✔Since the doppler shift only determines the component of the star's velocity that is
moving directly away or towards us, the star is typically moving faster than the
maximum speed astronomers measure. This means that the masses of the orbiting
planets are typically - ✔✔Underestimated
✔✔Which of the following properties can be inferred from the star's orbital period? -
✔✔The planets orbital radius
✔✔Is it possible to determine the planet's mass from the star's velocity curve? - ✔✔Yes,
by measuring the stars orbital period and its change in velocity over the orbit
✔✔Consider the planet that causes the stellar motion shown in Plot 2 (be sure you have
clicked the "Plot 2" button in the lower window of the animation). What can be said
about a different planet orbiting the same star with an orbital period of 500 days? -
✔✔The planet must be closer to the star
✔✔To determine a planet's average density, we can use - ✔✔the transit and Doppler
methods together.
✔✔What is planetary migration, and how may it account for the surprising orbits of
many extrasolar planets? - ✔✔Migration means the planet gradually moves closer to its
parent star. Many extrasolar planets are much closer to their stars than we had
expected. We think that it is possible for planets to migrate through their disks because
, of interactions with the gas in the disk. Migration can lead to resonances, which can
make orbits elliptical.
✔✔How can scientists account for the fact that extrasolar planets seem to come in a
wider range of types than the planets of our solar system? - ✔✔-The differences result
from migration, which in turn may result from a postponement of the clearing of the solar
nebula.
-Not all nebulas are alike - _some richer in planet-forming elements than others, and
some poorer.
✔✔Overall, does the nebular theory seem adequate for describing the origins of other
planetary systems? - ✔✔The nebular theory with the added processes of migration and
resonances accounts for the basic properties of extrasolar planetary systems.
✔✔Based on current evidence, how common are planetary systems? - ✔✔Kepler
spacecraft had discovered in total several thousand planet candidates during all the
time of its operation, most of them are thought to be real planets.
✔✔Based on current data, planetary systems appear to be - ✔✔present around at least
99% of all stars.
✔✔How do we think hot Jupiters formed? - ✔✔Hot Jupiters formed beyond the frost
line, as in our solar system, and migrated inward due to interaction with the solar
nebula.
✔✔Why didn't one form in our solar system? - ✔✔Because the nebula must have
dispersed shortly after the formation of our jovian planets.
✔✔What is an "extrasolar planet"? - ✔✔a planet that orbits a star that is not our own
Sun
✔✔What new process was added to our theory of planet formation to explain these
surprising extrasolar planets? - ✔✔Migration
✔✔What was so surprising about the first extrasolar planets that they forced a change
in our theory of planet formation? - ✔✔They were massive like Jupiter, but very close to
their host star.
✔✔If we can measure the period of a star's "wobble" caused by an orbiting planet, we
know the _______. - ✔✔period of the planet's orbit.
✔✔Why are planets with long orbital periods among the last to be discovered? -
✔✔Astronomers have to watch a long time before they repeat their orbits.
QUESTIONS SET A+
✔✔During a transit event, the absorption line of the star will be... - ✔✔Not shifted at all.
✔✔The gravitational force exerted on a star by a planet is equal to that exerted on the
planet by the star and in the opposite direction is... - ✔✔equal to that exerted on the
planet by the star and in the opposite direction
✔✔Since the doppler shift only determines the component of the star's velocity that is
moving directly away or towards us, the star is typically moving faster than the
maximum speed astronomers measure. This means that the masses of the orbiting
planets are typically - ✔✔Underestimated
✔✔Which of the following properties can be inferred from the star's orbital period? -
✔✔The planets orbital radius
✔✔Is it possible to determine the planet's mass from the star's velocity curve? - ✔✔Yes,
by measuring the stars orbital period and its change in velocity over the orbit
✔✔Consider the planet that causes the stellar motion shown in Plot 2 (be sure you have
clicked the "Plot 2" button in the lower window of the animation). What can be said
about a different planet orbiting the same star with an orbital period of 500 days? -
✔✔The planet must be closer to the star
✔✔To determine a planet's average density, we can use - ✔✔the transit and Doppler
methods together.
✔✔What is planetary migration, and how may it account for the surprising orbits of
many extrasolar planets? - ✔✔Migration means the planet gradually moves closer to its
parent star. Many extrasolar planets are much closer to their stars than we had
expected. We think that it is possible for planets to migrate through their disks because
, of interactions with the gas in the disk. Migration can lead to resonances, which can
make orbits elliptical.
✔✔How can scientists account for the fact that extrasolar planets seem to come in a
wider range of types than the planets of our solar system? - ✔✔-The differences result
from migration, which in turn may result from a postponement of the clearing of the solar
nebula.
-Not all nebulas are alike - _some richer in planet-forming elements than others, and
some poorer.
✔✔Overall, does the nebular theory seem adequate for describing the origins of other
planetary systems? - ✔✔The nebular theory with the added processes of migration and
resonances accounts for the basic properties of extrasolar planetary systems.
✔✔Based on current evidence, how common are planetary systems? - ✔✔Kepler
spacecraft had discovered in total several thousand planet candidates during all the
time of its operation, most of them are thought to be real planets.
✔✔Based on current data, planetary systems appear to be - ✔✔present around at least
99% of all stars.
✔✔How do we think hot Jupiters formed? - ✔✔Hot Jupiters formed beyond the frost
line, as in our solar system, and migrated inward due to interaction with the solar
nebula.
✔✔Why didn't one form in our solar system? - ✔✔Because the nebula must have
dispersed shortly after the formation of our jovian planets.
✔✔What is an "extrasolar planet"? - ✔✔a planet that orbits a star that is not our own
Sun
✔✔What new process was added to our theory of planet formation to explain these
surprising extrasolar planets? - ✔✔Migration
✔✔What was so surprising about the first extrasolar planets that they forced a change
in our theory of planet formation? - ✔✔They were massive like Jupiter, but very close to
their host star.
✔✔If we can measure the period of a star's "wobble" caused by an orbiting planet, we
know the _______. - ✔✔period of the planet's orbit.
✔✔Why are planets with long orbital periods among the last to be discovered? -
✔✔Astronomers have to watch a long time before they repeat their orbits.
