Question 1

An astronomer is trying to detect an exoplanet via the transit method. Which of these changes to a particular planet will make it EASIER to detect, if everything else about the planet is unchanged?

Accepted Answer

A)  increasing its radius 
B)  increasing its mass 
C)  increasing its orbital period 
D)  All of these are correct.

Question 2

Which of these pairs of exoplanet detection methods are MOST similar in the physical processes underlying the methods?

Accepted Answer

A)  The transit duration time variation and eclipsing binary minima variation methods 
B)  The astrometric and transit photometry methods 
C)  The phase cycle brightness and radial velocity methods 
D)  The distorted disk and radial velocity methods

Question 3

In order to detect multiple planets around a single star using the transit photometry method, the planets must have nearly the same

Accepted Answer

A)  orbital periods. 
B)  masses. 
C)  orbital plane. 
D)  diameters.

Question 4

Where in the universe are heavy elements with masses greater than that of helium being produced at this time?

Accepted Answer

A)  in the central cores of stars 
B)  in the surface layers of stars 
C)  at the event horizons of massive black holes 
D)  in the dark clouds of dust and gas

Question 5

An astronomer discovers a protoplanetary disk with spiral waves. This may be evidence for

Accepted Answer

A)  planetary nebulae. 
B)  jets from the young star. 
C)  planets in the disk. 
D)  comets.

Question 6

Which of these have been detected around nearby stars?

Accepted Answer

A)  Comets 
B)  Asteroids 
C)  terrestrial planets 
D)  All of these are correct.

Question 7

Exoplanets have been detected around binary stars through

Accepted Answer

A)  their effects on the spectra of the stars. 
B)  the slow increase in the orbital period of the stars, induced by the planet's gravity. 
C)  the slow decrease in the orbital period of the stars, induced by the planet's gravity. 
D)  their effects on the timing of eclipses of the stars.

Question 8

Asteroids have been detected around nearby stars through

Accepted Answer

A)  ripples observed in the protoplanetary disks around these stars. 
B)  hot dust generated by collisions amongst the asteroids. 
C)  reflected light from the star. 
D)  spectral lines from gas evaporated from the asteroids.

Question 9

What is the typical radius of the majority of extrasolar planets so far discovered?

Accepted Answer

A)  roughly the size of Earth 
B)  1.5-3 times the size of Earth 
C)  roughly the size of Jupiter 
D)  larger than Jupiter

Question 10

An astronomer is trying to detect an exoplanet via the radial velocity method. Which of these changes to a particular planet will make it harder to detect, if everything else about the planet is unchanged?

Accepted Answer

A)  decreasing its orbital period 
B)  decreasing its mass 
C)  decreasing its radius 
D)  decreasing its albedo

Question 11

The solar system was formed about how long after the Big Bang?

Accepted Answer

A)  immediately 
B)  a few hundred million years 
C)  9 billion years 
D)  13.8 billion years

Question 12

How many terrestrial exoplanets have been discovered to date with planets that could contain liquid water?

Accepted Answer

A)  none 
B)  fewer than a dozen 
C)  More than a dozen but less than 100 
D)  More than 100

Question 13

All of these are possible mechanisms believed to be capable of triggering the collapse of a cloud of gas and dust to form stars EXCEPT

Accepted Answer

A)  stellar winds may compress nearby gas and dust clouds. 
B)  a nearby supernova can compress nearby gas and dust clouds. 
C)  clouds can collide and compress each other. 
D)  radiation pressure from the cosmic microwave background can compress clouds of gas and dust.

Question 14

An astronomer is trying to detect an exoplanet via the astrometric method. Which of these changes to a particular planet will make it easier to detect, if everything else about the planet is unchanged?

Accepted Answer

A)  increasing its radius 
B)  increasing its mass 
C)  increasing its orbital period 
D)  All of these are correct.

Question 15

How was the vast majority of the hydrogen in the universe formed?

Accepted Answer

A)  in nuclear reactions in the cores of stars 
B)  in supernovae (exploding stars) 
C)  in the dark clouds of dust and gas 
D)  in the Big Bang, at the very beginning of the universe

Question 16

How far away is the nearest known exoplanet?

Accepted Answer

A)  0.42 light-year 
B)  4.2 light-years 
C)  42 light-years 
D)  42,000 light-years

Question 17

Which characteristic MOST directly determines whether a piece of material inside a dense core will eventually become part of the protostar or the protoplanetary disk that surrounds it?

Accepted Answer

A)  composition 
B)  kinetic energy 
C)  temperature 
D)  rotational speed

Question 18

Why do astronomers NOT believe that terrestrial exoplanets with orbits smaller than Mercury's orbit are relics of hot Jupiters in similar orbits?

Accepted Answer

A)  In our solar system, the two kinds of planets formed in different parts of the protoplanetary disk. 
B)  Observations of transiting hot Jupiters have shown that they are not losing their atmospheres. 
C)  The two kinds of planets have different compositions. 
D)  The terrestrial planets have more eccentric orbits than the hot Jupiters.

Question 19

Astronomers have searched for extrasolar planets for decades. Which one of these statements about the current status of the search is NOT true?

Accepted Answer

A)  No evidence of planets beyond our own solar system has been found. 
B)  Astronomers have seen disks of material around stars that resemble the solar nebula believed to be an early stage in the formation of our solar system. 
C)  Astronomers have seen asteroid belts around other stars. 
D)  Astronomers actually have images of other stars being orbited by planets.

Question 20

A particular star shows spectral lines of the lithium isotope 6Li. What conclusion do astronomers draw from this observation?

Accepted Answer

A)  The star has vaporized one of its planets that spiraled in too close to the star because the star's own 6Li was destroyed by nuclear reactions long ago. 
B)  The star has not yet begun nuclear reactions in its core because these reactions destroy 6Li. 
C)  Planets must be orbiting around the star because only planets show 6Li spectral lines. 
D)  The star is composed of pristine (unmodified) material from the Big Bang because 6Li has been destroyed in material that has been processed in stars and expelled back into space.

Exam 5: Exoplanets and the Formation of Planetary Systems