Deck 15: Exoplanets: Planetary Systems Beyond Our Own

Question 1

Around other suns, we have found Jupiters where Mercury is in our solar system.

Answer 1

True

Question 2

Some type of random event is likely needed to explain the highly tilted rotation axis ofUranus.

Answer 2

True

Question 3

The transmit method of detecting exoplanets works best when we can see the exoplanet'ssolar system edge on.

Answer 3

True

Question 4

Astronomers expect extrasolar planetary systems to have very different overall properties thanthose found in our solar system.

Question 5

Concerning our solar nebula theory, the presence of so many "hot Jupiters" gives usproblems with how they can form that close to their star.

Question 6

Using the radial velocity technique to determine the mass of exoplanets only yields an upperlimit to the mass of an exoplanet.

Question 7

Astronomers have determined the detailed composition of all confirmed exoplanets.

Question 8

Other solar systems formed in much the same way that our solar system formed.

Question 9

No exo-Earths have been found in the habitable zone of their stars.

Question 10

Planet formation happens in newly formed solar systems over the course of about 100 millionyears.

Question 11

Orbital resonances are a characteristic of some extrasolar systems but are not seen in oursolar system.

Question 12

We now know of over 100 jovian exoplanets, but no terrestrial planets around other starssimilar to the Sun.

Question 13

Most extrasolar planets are hot Jupiters, discovered in the infrared by the Spitzer Spacetelescope.

Question 14

The amplitude of the radial velocity curve showing the motion of a star with a planet orbitingit shows the period of the planet's orbit (the planet's year).

Question 15

One major difficulty with directly detecting exoplanets is that the planets are so much brighterthan their star that it is almost impossible to see the star in the glare from the planet.

Question 16

Super-Earths are earthlike planets where life is possible.

Question 17

Collisions or near collisions are necessary to explain the observed irregularities in our solarsystem.

Question 18

Most hot Jupiters are thought to have formed in the orbits they have been discovered.

Question 19

None of the other stars yet studied has more than one planet orbiting it.

Question 20

Astronomers expect that stars with multiple planets orbiting them are rare.

Question 21

Why has direct imaging found so few exoplanets?

A)Direct imaging is only possible using military satellites.
B)Direct imaging only works if the planet is orbiting a brown dwarf.
C)Only a few attempts have been made to directly image an extrasolar planet.
D)Exoplanets are faint and are usually close to their parent stars.

Question 22

Planets found in the habitable zone of other stars:

A)are all rocky planets, like the terrestrial planets in our solar system.
B)are all jovian planets.
C)include some Earths and super-Earths.
D)include hot Jupiters.
E)have been demonstrated to be barren of all life.

Question 23

The transit technique works best for:

A)exoplanets whose orbits are along our line of sight (edge on).
B)exoplanets whose orbits are perpendicular to our line of sight (face on).
C)exoplanets whose orbits are nearly circular (low eccentricity).
D)exoplanets whose orbits are very eccentric (very elliptical).

Question 24

So far, beyond the solar system the exoplanets found have been mostly:

A)large jovians orbiting solar-type stars about where our jovians are found.
B)large jovians with terrestrial-type orbits.
C)terrestrials very close to their star, and transiting its disk.
D)terrestrials with very elongated, distant orbits like comets.
E)brown dwarfs much more massive than Jupiter.

Question 25

The condensation theory is an example of:

A)a catastrophic theory.
B)a hot Jupiter theory.
C)a collision hypothesis.
D)an evolutionary theory.
E)a capture theory.

Question 26

What information do we know about the known exoplanets?

A)estimates of orbits and masses
B)complete composition
C)precise masses
D)all of the above
E)none of the above

Question 27

Which statement about extrasolar planets found to date is true?

A)All are terrestrials, comparable in size to Earth.
B)Few are found by Doppler shifts of their stars, due to their gravity.
C)All are more than 2 A.U. from their star.
D)Most have orbital periods of more than a year.
E)Some are so close to their stars that their periods are just a few days.

Question 28

All exoplanets found orbit their star in the same direction as the star's spin.

Question 29

Which molecule has not yet been detected in the atmospheres of exoplanets?

A)methane
B)carbon dioxide
C)oxygen
D)water

Question 30

When looking for the radial velocity changes detected due to Doppler shifts, which masscombination is most likely to be detected?

A)high mass star, high mass planet
B)high mass star, low mass planet
C)low mass star, high mass planet
D)low mass star, low mass planet
E)a high mass planet; the mass of the star is irrelevant

Question 31

Which of the following are irregularities in our solar system that must be explainable inmodels of planetary formation?

A)Venus's low rate of rotation
B)Mars' north-south asymmetry
C)the tilt of Uranus's rotation axis
D)binary Kuiper Belt objects
E)all of the above

Question 32

A late collision with a large planetesimal may have caused what feature on Mars?

A)Olympus Mons
B)its curious north-south asymmetry
C)Hellas Basin
D)the Marianas Trench
E)its exceptionally large nickel-iron core

Question 33

What role do the observed irregularities in our solar system play in developing models ofplanetary formation?

A)They are irrelevant to models of planetary formation.
B)They help confirm models that lead to random encounters.
C)They help reject models that allow for moons to have retrograde orbits.
D)They help reject models that allow for hot Jupiters.
E)They indicate that the condensation model is the only possible explanation of how solarsystems form.

Question 34

The radial velocity technique works best for:

A)exoplanets whose orbits are along our line of sight (edge on).
B)exoplanets whose orbits are perpendicular to our line of sight (face on).
C)exoplanets whose orbits are nearly circular (low eccentricity).
D)exoplanets whose orbits are very eccentric (very elliptical).

Question 35

When was the first confirmed exoplanet discovered?

A)shortly after the invention of the telescope, in the early 1600s
B)in prehistoric times
C)around 350 BC, by the Ancient Greeks
D)early in the 21st century
E)near the end of the 20th century

Question 36

As of late 2016, the number of confirmed exoplanets found was:

A)5, all around stars within 20 light-years of us.
B)42, all much bigger than Jupiter, but orbiting red dwarf stars.
C)a few hundred, orbiting more than 300 stars.
D)a few thousand, mainly around stars smaller and fainter than our Sun.
E)many thousands, around every star we have closely examined to date.

Question 37

Space telescopes looking for transiting planets look for small drops in brightness; these dropscan be detected if they are greater than about:

A)10%.
B)1%.
C)0.01%.
D)0.0001%.
E)any size.

Question 38

Eccentric Jupiters would eject any terrestrial planet from the planetary system where they arefound.

Question 39

The Kepler and CoRoT missions use which technique to detect planet candidates?

A)radial velocity measurements
B)direct imaging
C)measurements of transverse motion
D)planetary transits

Question 40

The direct detection method works best for:

A)exoplanets whose orbits are along our line of sight (edge on).
B)exoplanets that are close to their star.
C)exoplanets that are far from their star.
D)exoplanets that have already been detected by the transit method.

Question 41

The radius of a super-Earth generally falls in the range:

A)above 5 Earth radii.
B)between 2 and 5 Earth radii.
C)between 1.25 and 2 Earth radii.
D)between 0.75 and 1.25 Earth radii.
E)below 0.75 Earth radii.

Question 42

The radius of an exoplanet classified as a Neptune generally falls in the range:

A)above 5 Earth radii.
B)between 2 and 5 Earth radii.
C)between 1.25 and 2 Earth radii.
D)between 0.75 and 1.25 Earth radii.
E)below 0.75 Earth radii.

Question 43

A planet is located orbiting another star and its radius is about 3 times that of the Earth. It is:

A)a brown dwarf.
B)a Jupiter.
C)a Neptune.
D)a super-Earth.
E)an Earth.

Question 44

The planet ________ may have been the result of the merger of two bodies.

Question 45

Extrasolar planetary systems are similar to our solar system in all of the following ways,EXCEPT:

A)that planetary orbits are relatively coplanar.
B)for the presence of hot Jupiters in some systems.
C)that planets orbit in the same direction that their parent star rotates.
D)that the systems contain interplanetary debris, such as comets or asteroids.
E)None of these is dissimilar to our solar system.

Question 46

What is the difference between a hot Jupiter and a cold Jupiter?

A)Hot Jupiters have fusion reactions; cold Jupiters do not.
B)Hot Jupiters orbit close to the parent stars; cold Jupiters do not.
C)Hot Jupiters radiate more energy than they receive from their star; cold Jupiters do not.
D)Hot Jupiters have observed volcanoes; cold Jupiters do not.
E)Hot Jupiters were an exciting discovery; cold Jupiters were not.

Question 47

Gravitational microlensing detects planets when:

A)a background exoplanet passes almost directly behind its star.
B)a massive exoplanet orbits close to its star.
C)an exoplanet has an orbit that is perpendicular to our line of sight (face on).
D)a foreground exoplanet passes almost directly in front of its star.

Question 48

When we are lucky enough to see an extrasolar planet transit its star:

A)it will cause the star to vanish for several hours.
B)we can find the planet's size, mass, and density by the drop in light.
C)we can determine what elements are in its atmosphere.
D)we can determine its shape.
E)we can be certain it is a terrestrial, not a jovian.

Question 49

Why have very few planets with low mass (comparable to Mars or Mercury)been found?

A)These small planets are very rare.
B)Low mass planets do not produce large enough radial velocity changes in their stars.
C)High mass planets are blocking our views of low mass planets.
D)Hot Jupiters have ejected most low mass planets from their solar systems.
E)Low mass planets are too far from their parent stars to receive enough light to make themvisible from Earth.

Question 50

Super-Earths are:

A)planets that are most earthlike, likely to harbor life.
B)planets that are a few times the mass of the Earth.
C)planets that have earthlike masses, but orbit much closer to their star than the Earth does tothe Sun.
D)any rocky (or terrestrial)planet.
E)Earth-mass planets that are much lower in density than the Earth, giving them larger radii.

Question 51

According to the Solar Nebula theory, planets:

A)should be randomly oriented to their star's equator.
B)will revolve opposite the star's rotation.
C)should be a common result of star formation.
D)should be extremely rare.
E)should orbit perpendicular to their star's equator.

Question 52

In the process of planetary formation, when would the inward migration of Jupiters havemost likely occurred?

A)shortly after all of the planets had finished forming
B)just after the system was cleared of the remaining gas
C)before these planets had grown to full size
D)after these planets had reached full size, but before terrestrial planets had finished forming
E)at least hundreds of millions of years after planetary formation ended

Question 53

The habitable zone is the area around a star where:

A)planets with life have been found.
B)human beings could live.
C)the greenhouse effect is possible.
D)a planet could have an atmosphere.
E)temperatures are suitable for planets to have liquid water.

Question 54

Hot Jupiters are thought to have moved closer to their parent star than where they originateddue to:

A)gravitational interactions with the gas disk.
B)magnetic attraction to the parent star.
C)interactions with another star.
D)large impacts.
E)many small impacts.

Question 55

Most extrasolar Neptunes and Jupiters found to date have:

A)orbits very close to their parent stars, making them hot Neptunes and hot Jupiters.
B)orbits that are more eccentric than those of planets in our solar system, with eccentricitiesgreater than 0.1.
C)orbits that are less eccentric than those of planets in our solar system, with eccentricities lessthan 0.01.
D)much larger orbits than the jovian planets in our solar system.

Question 56

Beyond our own solar system, the planets found to date have tended to be:

A)Kuiper Belt objects, far from the glare of their suns.
B)large jovians far from stars like our Sun.
C)large jovians with orbits more like terrestrial planets.
D)terrestrials very close to their star, and transiting its disk.
E)imaginary, with no present proof that they really exist.

Question 57

In comparing our own solar system with others found to date, we find:

A)most orbits are less circular than the orbits of planets around our Sun.
B)jovians often lie much closer to their suns than ours do.
C)multiple planets are found in some systems.
D)hot Jupiters, even closer to their stars than Mercury is to our Sun.
E)all of the above.

Question 58

Of the first exoplanets found, most were detected by:

A)noting the drop in the star's light as the planet transits its disk.
B)imaging them with the HST in the infrared, where they are easier to spot.
C)noting the Doppler shifts of the star as the planet orbits it.
D)receiving radio transmissions from them, much like Jupiter emits.
E)detecting the oxygen in their atmospheres spectroscopically.

Question 59

________ in the early solar system might explain many of the observed irregularities.

Question 60

The habitable zone is largest for:

A)brown dwarfs.
B)red dwarfs.
C)white dwarfs.
D)red giants.
E)blue giants.

Question 61

Explain how the Doppler Effect has been used to detect invisible planets orbiting other Sun-like stars.

Question 62

How can astronomers be confident that the larger exoplanets discovered are not simply browndwarfs?

Question 63

How do most of the newly discovered solar systems and planets compare to our own?

Question 64

Why do instruments that are looking for transiting planets need to look for very smallbrightness changes?

Question 65

The Earth-Moon system may have been the result of a collision between the Earth and a(n)________-size object.

Question 66

Describe an example of the creation of an object due to a random event in our solar system.

Question 67

Compare and contrast the types of planets that can be found by the radial velocity techniquewith those that can be found by the transit method.

Question 68

The ________ around a star is the region where liquid water could exist on a planet.

Question 69

Extrasolar planets are placed in groups by their approximate masses. What are four of theseclasses?

Question 70

Exoplanets are divided into four groups based on their radii. These groups are generallynamed after planets in our solar system. What are these 4 groups, and what is the approximaterange of radii for planets in each?

Question 71

Describe two methods that have already been used to study extrasolar planets, and which onegives us the most information.

Question 72

What are some of the properties of objects in the solar system that a theory of its origin DOESNOT need to account for? Explain.

Question 73

Hot Jupiters have ________ period orbits.

Question 74

The Kepler mission uses the ________ technique to detect exoplanets.

Question 75

The ________ theory is thought to explain the formation of our solar system.

Question 76

Why does the present method of finding extrasolar planets not favor finding solar systems likeours?

Question 77

Discuss the important features that allow space-based telescopes to search for transitingexoplanets.

Question 78

The ________ method finds exoplanets by the small brightness change caused when anexoplanet passes in front of a background star, causing the light to magnify.

Question 79

Why are infrared observations useful when observing extrasolar planets?

Question 80

The radial velocity method is less likely to detect low mass planets than high mass planetsbecause low mass planets cause smaller ________ fluctuations.