Astronomy ch. 10 Eisenhower
The majority of extrasolar planets are estimated to be gas giants.
False
Most extrasolar planets discovered using the Doppler method
are more massive than Earth and orbit very close to the star
Which planet search technique is currently best suited to finding Earth-like planets?
Transit
Indirect detection of an extrasolar planet means ________.
observing the planet's effect on its host star
What must be true about the orbit of a planet discovered by the transit method?
As seen from Earth, the planet's orbit must be nearly parallel to our line of sight.
Once a planet forms in a disk-like nebula around a star, its orbit is fixed and will never change.
False
The Doppler technique for planet detection has found Earth-like planets around nearby Sun-like stars
False
Which of the following methods has led to the most confirmed discoveries of massive planets orbiting near their parent stars?
It has been modified to allow for planets to migrate inwards or outwards due to gravitational interactions.
A star is seen to have two transiting planets. Planet 1 transits every 3 months, and Planet 2 transits every 15 months. What can we infer about their orbits?
Planet 2's semimajor axis is larger than Planet 1'
Consider a star with 2 planets. The mass of planet A is the same as the mass of planet B. The orbit of Planet A is on average, closer to the star than the orbit of Planet B. Which of the following statements is true?
Planet A is, on average, moving faster than Planet B.
What is the chief difficulty in attempting to detect planets around other stars?
Planets do not emit visible light, and they are typically at least a billion times fainter than their host stars.
You observe a star very similar to our own Sun in size and mass. This star moves very slightly back and forth in the sky once every 4 months, and you attribute this motion to the effect of an orbiting planet. What can you conclude about the orbiting planet?
The planet must be closer to the star than Earth is to the Sun
What must be true in order for astronomers to be able to use the Doppler method to determine a planet's true mass?
The planet's orbit must be viewed nearly edge on.
Why are many of the newly detected extrasolar planets called "hot Jupiters"?
Their masses are similar to Jupiter but they are very close to the central star and therefore hot.
How do we think the "hot Jupiters" around other stars were formed?
They formed as gas giants beyond the frost line and then migrated inwards.
What was so surprising about the first extrasolar planets discovered?
They were Jupiter-like planets orbiting very close to their stars.
Astronomers have discovered more extrasolar planets around other stars than the number of planets in our own Solar System.
True
What is an "extrasolar planet"?
a planet that orbits a star that is not our own Sun
What is a so-called "hot Jupiter"?
a planet with a mass similar to Jupiter but very close to the central star and therefore hot
Direct detection of an extrasolar planet means ________.
acquiring images or spectra of the planet
The transit method of planet detection works best for
big planets in edge-on orbits around small stars.
How can astronomers measure the composition of an extrasolar planet's atmosphere?
by comparing spectra from when the planet is in transit with spectra taken at other times
What type of observation can astronomers use to measure the composition of an extrasolar planet's atmosphere?
comparisons of a star's spectrum when the planet is in transit versus when it is eclipsed
According to the nebular theory, where should jovian planets form?
in the cold outer regions of the disk, where rocks, metals, and ices can condense
The Doppler method can be used to measure the orbital period of a planet by
measuring the time it takes for the star's line-of-sight velocity to cycle from peak to peak.
What mechanism explains the presence of "hot Jupiters" around other stars?
planetary migration caused by gravitational interactions with other planets, or with material in the disk
The reason that most extrasolar planets discovered by the Doppler method are found close to their parent stars is
the wavelength shift of the star's spectrum is larger.
