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star #3

Terms in this set (26)

What is an extrasolar planet?

A planet that orbits a star that is not our own Sun

A planet that is considered an "extra," in that it was not needed for the formation of its solar system

A planet that is larger than the Sun

A planet that is extra large compared to what we'd expect
A planet that orbits a star that is not our own Sun
"Extrasolar" means "beyond the Sun."
The first confirmed detections of extrasolar planets occurred in ____________.

2009

the mid-20th century

the 1990's

the mid-17th century
the 1990's
Among the first few hundred extrasolar planets, most were discovered by ____________.

the Doppler technique

the astrometric technique

the Hubble Space Telescope

the transit technique
the Doppler technique
What information does the Doppler technique give about an extrasolar planet?

the planet's radius

the planet's minimum mass

the planet's density

all of the above
the planet's minimum mass
Why do we say that the Doppler technique gives the planet's "minimum mass"?

The size of the Doppler shift that we detect depends on whether the planet's orbit is tilted.

The size of the Doppler shift that we detect depends on knowing the star's mass, which can be very uncertain.

Doppler measurements are very difficult, producing noisy data that often cause astronomers to underestimate a planet's mass.

Extrasolar planets are always increasing in mass.
The size of the Doppler shift that we detect depends on whether the planet's orbit is tilted.
Which detection techniques can find the planet's orbital distance (assuming we know the mass of the star)?

only the transit technique

only the astrometric technique

only the Doppler technique

all of these techniques
all of these techniques
Which of the following statements is not true about the planets so far discovered around other stars?

Most of them are much more massive than Earth.

Photographs reveal that most of them have atmospheres much like that of Jupiter.

Many of them have been discovered by observing Doppler shifts in the spectra of the stars they orbit.

Many of them orbit closer to their star than Jupiter orbits the Sun.
Photographs reveal that most of them have atmospheres much like that of Jupiter.
What is the closest that extrasolar planets have been found to their stars?

nearer to their stars than Earth to the Sun

nearer to their stars than Mercury to our Sun

unknown: we do not know the distance with enough accuracy to say

nearer to their stars than Saturn to the Sun
nearer to their stars than Mercury to our Sun
Based on available data, what kind of objects in our solar system do most of the known extrasolar planets resemble?

jovian planets

Kuiper belt objects

terrestrial planets

none of the above: most extrasolar planets apparently belong to some new category of object
jovian planets
Which of the following orbital characteristics has not been observed among any known extrasolar planets?

Orbits that are not elliptical.

Orbits that take the planets much closer to their star than Mercury orbits the Sun.

Orbits that are much more eccentric than the orbits of planets in our own solar system.

Orbital speeds that are so slow that we cannot explain them.
Orbital speeds that are so slow that we cannot explain them.
Which new idea has been added into our theory of solar system formation as a result of the discoveries of extrasolar planets?

In some star systems, it is possible for jovian planets to form in the inner solar system and terrestrial planets to form in the outer solar system.

In addition to the categories of terrestrial and jovian, there must be an "in-between" category of planet that has the mass of a jovian planet but the composition of a terrestrial planet.

Some of the "exceptions to the rules" in our own solar system are likely to have been the result of giant impacts.

Jovian planets can migrate from the orbits in which they are born.
Jovian planets can migrate from the orbits in which they are born.
In essence, the Kepler is searching for extrasolar planets by ____________.

obtaining high-resolution photographs of other star systems

monitoring stars for slight dimming that might occur as unseen planets pass in front of them

observing Doppler shifts in a star's spectrum caused by an unseen planet

looking for slight back and forth shifts in a star's position in our sky
monitoring stars for slight dimming that might occur as unseen planets pass in front of them
In essence, most of the first few hundred extrasolar planets discovered were found by___________.

observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet

taking high-resolution photographs of other star systems

observing mini-eclipses of a star as an unseen planet passes in front of it

identifying spectral lines that look like what we expect to see from a planet rather than a star
observing a star carefully enough to notice that it is experiencing a gravitational tug caused by an unseen planet
Why is it so difficult to take pictures of extrasolar planets?

No telescope is powerful enough to detect the faint light from a distant planet.

Telescopes are too busy with other projects.

Extrasolar planets give off light at different wavelengths than planets in our solar system.

Their light is overwhelmed by the light from their star.
Their light is overwhelmed by the light from their star.
The astrometric technique looks for planets with careful measurements of a star's _________.

velocity towards or away from us

brightness

position in the sky

all of the above
position in the sky
Suppose you are using the Doppler technique to look for planets around another star. What must you do?

Compare many spectra of the star taken over a period of many months or years.

Compare many spectra of an orbiting planet taken over a period of many months or years.

Compare the brightness of the star over a period of many months or years.

Carefully examine a single spectrum of an orbiting planet.

Carefully examine a single spectrum of the star.
Compare many spectra of the star taken over a period of many months or years.
In general, which type of planet would you expect to cause the largest Doppler shift in the spectrum of its star?

a massive planet that is far from its star

a massive planet that is close to its star

a low-mass planet that is close to its star

a low-mass planet that is far from its star
a massive planet that is close to its star
Suppose a planet is discovered by the Doppler technique and is then discovered to have transits. In that case, we can determine all the following about the planet except ______________.

its rotation period

its physical size (radius)

its orbital period

its density

its precise mass
its rotation period
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 have a mass about the same as the mass of Jupiter.

The planet must be farther from the star than Neptune is from the Sun.

The planet must be closer to the star than Earth is to the Sun.

You do not have enough information to say anything at all about the planet.
The planet must be closer to the star than Earth is to the Sun.
All the following statements about known extrasolar planets are true. Which one came as a surprise to scientists who expected other solar systems to be like ours?

Some of the planets orbit their star more closely than Mercury orbits the Sun.

In some cases, we've found more than one planet orbiting the same star.

Most of the planets orbit stars that are quite nearby compared to the scale of the entire Milky Way Galaxy.

Most of the planets are quite massive - much more like Jupiter than like Earth.
Some of the planets orbit their star more closely than Mercury orbits the Sun.
Which of the following is not expected for a "hot Jupiter" that orbits 0.05 AU from its star

cloudtop temperatures over 1000 K

density similar to or lower than Jupiter's

clouds made of rock dust

intense volcanism
intense volcanism
Based on everything you have learned about the formation of our solar system, which of the following statements is probably not true?

Only a tiny percentage of stars are surrounded by spinning disks of gas during their formation.

Other solar systems will also have planets in the two basic categories of terrestrial and jovian.

Planets always tend to orbit their star in the same direction and approximately the same plane.

Other planetary systems will have far more numerous asteroids and comets than actual planets.
Only a tiny percentage of stars are surrounded by spinning disks of gas during their formation.
To date, we've found very few planets orbiting their stars at distances comparable to the distances of the jovian planets in our solar system. Why do astronomers think this is the case?

We have not yet been searching for planets at such distances for a long enough time.

Planets at such distances are probably very low in mass.

Planets at such distances are extremely rare.

No known technique can detect planets at such large distances.
We have not yet been searching for planets at such distances for a long enough time.
Current evidence suggests that many massive jovian planets orbit at very close orbital distances to their stars. How do we think these planets ended up on these close orbits?

These planets were captured from other solar systems.

These planets are jovian in nature and were able to form close to their stars because their solar nebulas were very cold in temperature.

These planets migrated inward after being born on orbits much farther from their stars.

Despite their large masses, these planets are terrestrial in nature and therefore could form in their inner solar systems.
These planets migrated inward after being born on orbits much farther from their stars.
Assuming that our ideas about how "hot Jupiters" ended up on their current orbits are correct, why didn't our own solar system end up with any hot Jupiters?

Our jovian planets must have migrated outward from inside the orbit of Mercury.

The existence of Earth and the other terrestrial planets prevented the jovian planets from migrating inward.

Our solar nebula must have stuck around for an unusually long time after the formation of jovian planets.

Our solar nebula must have been blown into space shortly after the formation of the jovian planets.
Our solar nebula must have been blown into space shortly after the formation of the jovian planets.
When is the soonest we are likely to have images and spectra of Earthlike planets around other stars?

In a decade or two, through space observatories now in the early planning stages.

In just a few years, through analysis of observations by the Kepler mission.

Any day now, thanks to our largest ground-based telescopes.

We already have images and spectra of Earthlike planets around other stars.
In a decade or two, through space observatories now in the early planning stages.
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