Deck 15: Exoplanets: Planetary Systems Beyond Our Own

Question 1

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

Answer 1

False

Question 2

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

Answer 2

False

Question 3

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

Answer 3

True

Question 4

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 5

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

Question 6

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

Question 7

Most scientists think catastrophes played little role in the solar system's history.

Question 8

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

Question 9

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 10

It is expected that most of the planet candidates found by the Kepler mission will eventually be confirmed.

Question 11

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

Question 12

Super-Earths are earthlike planets where life is possible.

Question 13

Some type of catastrophe is likely needed to explain the highly tilted rotation axis of Uranus.

Question 14

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

Question 15

Eccentric Jupiters would probably eject any terrestrial planet from the planetary system where they are found.

Question 16

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

Question 17

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

Question 18

The Collision Hypothesis and Evolutionary Theories are considered to be equally plausible explanations of how planetary systems form.

Question 19

Astronomers have determined the detailed composition of all confirmed exoplanets.

Question 20

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

Question 21

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

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

Question 22

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 stop.
C) noting the Doppler shifts of the star as the planet orbits it from side to side.
D) receiving radio transmissions from them, much like Jupiter emits.
E) detecting the oxygen in their atmospheres spectroscopically.

Question 23

What role do the observed irregularities in our solar system play in developing models of planetary 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 solar systems form.

Question 24

The Doppler radial velocity technique works best for:

A) planets whose orbits are along our line of sight.
B) planets whose orbits are perpendicular to our line of sight.
C) planets whose orbits are nearly circular.
D) planets whose orbits are very eccentric.

Question 25

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 26

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 27

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 to the 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 28

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 eccentricities greater than 0.1.
C) orbits that are less eccentric than those of planets in our solar system, with eccentricities less than 0.01.
D) much larger orbits than the jovian planets in our solar system.

Question 29

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 30

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 lie 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 31

Which of these is NOT a consequence of resonance?

A) the Moon's periods of rotation and revolution are equal
B) the orbital periods of Neptune and Pluto
C) the Kirkwood Gaps in the asteroid belt
D) Venus' cloud and surface rotation rates
E) Mercury's rotation and revolution around the Sun

Question 32

When we are lucky enough to see an extra-solar 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 33

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

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

Question 34

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 35

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 36

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 37

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 38

Space telescopes looking for transiting planets look for small drops in brightness; these drops are:

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

Question 39

When looking for the radial velocity changes or "wobbles" detected due to Doppler shifts,which mass combination 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 40

"Catastrophes" are NOT needed to explain:

A) the exceptionally large nickel-iron core of Mercury.
B) the asteroid belt.
C) our Moon.
D) the tilt of Uranus.
E) the appearance of Miranda's surface.

Question 41

The ________ hypothesis was considered plausible in the 1800s,but is it no longer taken seriously.

Question 42

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

Question 43

To reach the nearest known exoplanet using current technology would take:

A) a matter of months.
B) 4.4 years.
C) about a century.
D) about 40,000 years.
E) close to a million years.

Question 44

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 45

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 46

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 47

As of early 2013,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) over 400, orbiting more than 300 stars.
D) about 900, mainly around stars much smaller and fainter than our Sun.
E) thousands, around every star we have closely examined to date.

Question 48

The Kepler mission uses the ________ technique to detect exoplanets.

Question 49

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

Question 50

Hot Jupiters are thought to have moved closer to their parent star than where they originated due 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 51

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

Question 52

In the process of planetary formation,when would the inward migration of Jupiters have most 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

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 54

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

Question 55

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 them visible from Earth.

Question 56

The habitable zone is largest for:

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

Question 57

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

Question 58

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 are dissimilar to our solar system.

Question 59

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 60

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 61

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

Question 62

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

Question 63

Why are Earths and super-Earths in the habitable zones of their stars of special interest?

Question 64

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

Question 65

Hot Jupiters have ________ period orbits.

Question 66

What are some of the properties of objects in the solar system that a theory of its origin DOES NOT need to account for? Explain.

Question 67

Describe an example of catastrophic creation in our solar system.

Question 68

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

Question 69

Why are infrared observations useful when observing extrasolar planets?

Question 70

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

Question 71

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

Question 72

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

Question 73

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

Question 74

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