Deck 11: Habitability Outside the Solar System

Question 1

When a star exhausts the hydrogen fuel in its core it

A) expands at a constant temperature
B) expands and heats up
C) expands and cools
D) shrinks and heats up

Answer 1

expands and cools

Question 2

What is the least common class of star in our galaxy?

A) A-type
B) M-type
C) O-type
D) G-type

Answer 2

O-type

Question 3

Which is the following is the spectra sequence in order of increasing temperature:

A) MKGFAOB
B) OBFAKGM
C) FGBAKMA
D) OBAFGKM

Answer 3

MKGFAOB

Question 4

The total amount of energy that a star radiates out into space is referred to as its

A) radiance
B) luminosity
C) surface temperature
D) apparent brightness

Question 5

When a low mass star like our Sun dies it will

A) eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a white dwarf
B) eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a neutron star
C) explode as a supernova forming a supernova remnant, leaving behind a dead star called a white dwarf
D) explode as a supernova forming a supernova remnant, leaving behind a dead star called a neutron star

Question 6

When our Sun becomes a red giant it will grow so large that it will

A) engulf the entire solar system
B) engulf some of the inner planets
C) extend out nearly to the orbit of Mercury
D) engulf some of the outer planets

Question 7

A star less massive than our Sun

A) will have a longer lifetime
B) will have a shorter lifetime
C) will have the same lifetime as the Sun
D) could have either a longer lifetime or a shorter lifetime depending on its chemical composition

Question 8

When a star much more massive than our Sun dies it will

A) eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a white dwarf
B) eject its outer layers into space forming a planetary nebula, leaving behind a dead star called a neutron star
C) explode as a supernova forming a supernova remnant, leaving behind a dead star called a white dwarf
D) explode as a supernova forming a supernova remnant, leaving behind a dead star called a neutron star

Question 9

Stars spend 90% of their lives

A) fusing hydrogen into helium in their cores and slowly dimming
B) slowly dimming as they die with no fusion occurring in their cores
C) as slowly brightening protostars
D) fusing hydrogen into helium in their cores and slowly brightening

Question 10

The luminosity of a star is

A) determined by its apparent brightness and surface temperature
B) only determined by its distance
C) only determined by its surface temperature
D) determined by its apparent brightness and distance

Question 11

Which of the following stars is the hottest?

A) M7
B) A0
C) G6
D) B4

Question 12

What is the spectral type of the Sun?

A) K9
B) G2
C) F7
D) A2

Question 13

One of the fundamental principles of stellar evolution is that the more massive a star is

A) the more heavy elements it contains
B) the more planets it has around it
C) the faster it evolves
D) the slower it evolves

Question 14

Which of the following are in order of decreasing temperature?

A) O9, F2, F7, G2, K0
B) K0, G2, F7, F2, O9
C) F7, F2, O9, K0, G2
D) O9, F7, F2, G2, K0

Question 15

A star more massive than our Sun

A) will have a longer lifetime
B) will have a shorter lifetime
C) will have the same lifetime as the Sun
D) could have either a longer lifetime or a shorter lifetime depending on its chemical composition

Question 16

The most fundamental property of star is its

A) size
B) mass
C) chemical composition
D) surface temperature

Question 17

In our search for stars with habitable planets, we are mostly interested in

A) giants and supergiants that have very wide habitable zones
B) dead stars like white dwarfs and neutron stars
C) stable, long-lived hydrogen-fusing stars
D) stars in the process of formation

Question 18

Which is the following is the spectra sequence in order of decreasing temperature:

A) MKGFAOB
B) OBFAKGM
C) FGBAKMA
D) OBAFGKM

Question 19

Which of the following stars is the coolest?

A) B7
B) G9
C) K7
D) K4

Question 20

What is the most common class of star in our galaxy?

A) G-type
B) O-type
C) M-type
D) A-type

Question 21

Even though K- and M-type stars are suitable for life, why might they not have many habitable planets around them?

A) because their habitable zones are very wide
B) because their habitable zones are very narrow
C) because their lifetimes are too short
D) because they contain too few heavy elements to form planets

Question 22

Which of the following could be a stable planetary orbit in a binary system?

A) a large orbit around both stars in a wide binary system
B) an orbit close to one of the stars in a wide binary system
C) a "figure-of-eight" orbit about both stars in a close binary system
D) an orbit close to one of the stars in a close binary system

Question 23

Which type of stable planetary orbit would be best in a wide binary system?

A) a large elliptical orbit around both components
B) a large circular orbit around both components
C) a "figure-of-eight" orbit around both components
D) an orbit close to one of the components

Question 24

Brown dwarfs have

A) very narrow habitable zones
B) no habitable zones
C) very wide habitable zones
D) habitable zones similar to the Sun

Question 25

G-, K-, and M-type stars

A) do not contain enough heavy elements to form planets
B) have lifetimes long enough for planets to form and for simple life to appear, but not long enough for advanced life to develop
C) have lifetimes too short for planet formation
D) have lifetimes long enough for advanced life to evolve

Question 26

Brown dwarfs are

A) stars in the process of forming
B) very cool, low mass stars of spectral type M
C) the burnt out cores of dead stars
D) objects with insufficient mass to sustain nuclear fusion in their cores

Question 27

O-type stars in our galaxy are

A) very common, making up about 50% of the total
B) fairly common (several percent)
C) very rare (less than 1%)
D) the most common type of stars in our galaxy (75% or more)

Question 28

The percentage of sun-like stars in our galaxy that are in multiple star systems is approximately

A) 60 %
B) 30 %
C) 50 %
D) 75 %

Question 29

Which of the following could be a stable planetary orbit in a binary system?

A) a large orbit around both stars in a close binary system
B) a "figure-of-eight" orbit about both stars in a close binary system
C) an orbit close to one of the stars in a close binary system
D) a large orbit around both stars in a wide binary system

Question 30

Which of the following types of stars are suitable for advanced life?

A) A-type
B) F-type
C) O-type
D) K-type

Question 31

O-type stars

A) have lifetimes long enough for advanced life to evolve
B) have lifetimes long enough for planets to form and for life to appear, but not long enough for advanced life
C) do not contain enough heavy elements to form planets
D) have lifetimes too short for planet formation

Question 32

Brown dwarfs occupy the range of masses between

A) white dwarfs and neutron stars
B) giants and supergiants
C) terrestrial and Jovian planets
D) large planets and small stars

Question 33

Overall, multiple star systems in our galaxy

A) are extremely rare, making up less than 1% of the total
B) are very common, making up about 60% of the total
C) are fairly common, making up around 30% of the total
D) do not exist

Question 34

Which of the following types of stars are NOT suitable for advanced life?

A) K-type
B) M-type
C) G-type
D) F-type

Question 35

A- and F-type stars

A) do not contain enough heavy elements to form planets
B) have lifetimes long enough for advanced life to evolve
C) have lifetimes too short for planet formation
D) have lifetimes long enough for planets to form and for simple life to appear, but not long enough for advanced life to develop

Question 36

Solar-type stars in our galaxy are

A) very common, making up about 50% of the total
B) very rare (less than 1%)
C) fairly common (several percent)
D) the most common type of stars in our galaxy (75% or more)

Question 37

B-type stars have lifetimes

A) long enough for advanced life to evolve
B) too short for planet formation
C) long enough for planets to form but not for life to appear
D) long enough for planets to form and for simple life to appear, but not long enough for advanced life to develop

Question 38

Even though M-stars have very narrow habitable zones, they may still host a large number of inhabited worlds because they are so

A) common
B) cool
C) long lived
D) small

Question 39

M-type stars in our galaxy are

A) fairly common (several percent)
B) the most common type of stars in our galaxy (75% or more)
C) very common, making up about 50% of the total
D) very rare (less than 1%)

Question 40

Brown dwarfs have

A) very wide habitable zones
B) no habitable zones at all
C) narrow habitable zones
D) habitable zones similar to the Sun

Question 41

Which of the following methods has been the LEAST successful in detecting extrasolar planets around other star systems?

A) regular changes in the positions of the parent stars with respect to more distant stars as they move across the sky
B) detection of Doppler shifts in the spectra of the parent stars
C) detection of brightness changes in a star as a planet passes in front of it
D) detection of reflected starlight

Question 42

Which of the following methods uses astrometry to detect extrasolar planets around other star systems?

A) detection of Doppler shifts in the spectra of the parent stars
B) detection of reflected starlight
C) detection of brightness changes in a star as a planet passes in front of it
D) regular changes in the positions of the parent stars with respect to more distant stars as they move across the sky

Question 43

Stars only exhibit a Doppler shift if they are moving

A) away from us along the line of sight
B) perpendicular to our line of sight
C) in a circular motion about us
D) toward or away from us along the line of sight

Question 44

A nearby star is discovered to have a high mass planet at a very small distance form it. What would its radial velocity curve look like?

A) large amplitude, short wavelength
B) small amplitude, long wavelength
C) small amplitude, short wavelength
D) large amplitude, long wavelength

Question 45

Which of the following methods has been the MOST successful in detecting extrasolar planets around other star systems?

A) regular changes in the positions of the parent stars with respect to more distant stars as they move across the sky
B) detection of brightness changes in a star as a planet passes in front of it
C) detection of Doppler shifts in the spectra of the parent stars
D) detection of reflected starlight

Question 46

Which of the following extrasolar planets would be the most difficult to detect using the Doppler shift method?

A) a low mass planet far from its parent star
B) a massive planet close to its parent star
C) a low mass planet close to its parent star
D) a massive planet far from its parent star

Question 47

The wavelengths of radiation from a star that is moving away from us

A) can be longer or shorter depending on the distance to the star
B) are shorter than if the star were not moving
C) are the same as if the star were not moving
D) are longer than if the star were not moving

Question 48

Why does the Doppler shift method of detecting extrasolar planets only give us the minimum mass of a planet?

A) because we don't necessarily know the density of the planet
B) because we don't necessarily know the angle the planet's orbit makes with our line of sight
C) because we don't necessarily know the diameter (size) of the planet
D) because we don't necessarily know the mass of the parent star very

Question 49

The wavelengths of radiation from a star that is moving toward us

A) can be longer or shorter depending on the distance to the star
B) are shorter than if the star were not moving
C) are longer than if the star were not moving
D) are the same as if the star were not moving

Question 50

In an extrasolar planetary system containing a single planet, the parent star is measured to move about its center of mass every 24 years. Given this, what is the orbital period of the planet?

A) 48 years
B) this cannot be determined from this observation
C) 12 years
D) 24 years

Question 51

The radial velocity curve of a star with an extrasolar planet is a plot of radial velocity against

A) luminosity
B) brightness
C) distance
D) time

Question 52

The third planet discovered around the star Gliese 876 is designated as

A) Gliese876c
B) 3 Gliese876
C) Gliese876d
D) Gamma Gliese 876

Question 53

The center of mass of the solar system is

A) midway between the Sun and Jupiter
B) exactly at the center of the Sun
C) just outside the orbit of Mercury
D) close to center but not exactly at the center of the Sun

Question 54

If a star has an extrasolar planet, the wavelength of its radial velocity curve is related to the planet's

A) orbital shape
B) radius
C) mass
D) orbital period

Question 55

The wavelengths of radiation from a star that is moving perpendicular to us

A) can be longer or shorter depending on the distance to the star
B) are shorter than if the star were not moving
C) are longer than if the star were not moving
D) are the same as if the star were not moving

Question 56

In most extrasolar planetary systems the center of mass is likely to be located

A) midway between the star and its most massive planet
B) close to the center of the parent star
C) exactly at the center of the parent star
D) close to the center of the most massive planet

Question 57

If a star has an extrasolar planet, the amplitude of its radial velocity curve is related to the planet's

A) mass
B) orbital shape
C) orbital period
D) radius

Question 58

When we measure the mass of a planet using the Doppler shift method, we know that it is mass

A) could well be smaller
B) could be larger or smaller
C) is exactly as measured
D) could well be larger

Question 59

Which of the following extrasolar planets would be easiest to detect using the Doppler shift method?

A) a massive planet far from its parent star
B) a low mass planet far from its parent star
C) a low mass planet close to its parent star
D) a massive planet close to its parent star

Question 60

If a star has an extrasolar planet, the symmetry of its radial velocity curve is related to the planet's

A) orbital shape
B) mass
C) radius
D) orbital period

Question 61

Which of the following methods allows us to determine the size of an extrasolar planet around another star?

A) detection of brightness changes in a star as a planet passes in front of it
B) detection of reflected starlight
C) regular changes in the positions of the parent stars with respect to more distant stars as they move across the sky
D) detection of Doppler shifts in the spectra of the parent stars

Question 62

Most of the extrasolar planets detected by the Doppler technique are found

A) at about the same distance as the Earth is from the Sun
B) very close to their parent stars
C) at about the same distance as the planet Jupiter is from the Sun
D) very far from their parent stars

Question 63

When an exoplanet passes in front of its parent star, we call this

A) an eclipse
B) a shadow event
C) a transit
D) an occultation

Question 64

The great insight gained from the discovery of exoplanets is that planetary systems

A) are extremely rare
B) exist around every star in our galaxy
C) appear to be common
D) are only found around sun-like stars

Question 65

For the transit of an extrasolar planet to be observed, the

A) orbital plane of the planet has to be aligned along our line of sight
B) planet has to be very large
C) orbital plane has to be perpendicular to our line of sight
D) parent star has to be very small

Question 66

Which of the following best describes the most common type of extrasolar planet discovered to date?

A) cool Jovian
B) super terrestrial
C) cool terrestrial
D) hot Jovian

Question 67

The few extrasolar planets that have been detected directly to date are

A) very large and at great distances from their parent stars
B) small and at great distances from their parent stars
C) small and close to their parent stars
D) very large and close to their parent stars

Question 68

The recently discovered rocky terrestrial-like exoplanets with masses a few times that of the Earth are sometimes called

A) mega Earths
B) super Earths
C) colossal Earths
D) heavy Earths

Question 69

Why is it better to search for extrasolar planets directly using infrared (IR) rather than visible radiation?

A) the planet doesn't reflect any visible radiation, only IR radiation
B) the star doesn't emit any IR radiation because it is too hot
C) the visible light from planets will be blocked by interstellar dust along our line of sight while the IR radiation will not
D) the planet emits more IR radiation than it reflects in the visible

Question 70

The orbits of most extrasolar planets detected to date are

A) parabolic
B) highly elliptical
C) perfectly circular
D) slightly elliptical

Question 71

The decrease in brightness observed when a transiting exoplanet passes in front of its parent star is a measure of the exoplanet's

A) mass
B) temperature
C) size
D) chemical composition

Question 72

If we are eventually able to detect Earth-like extrasolar planets directly, they will be seen very

A) close to their parent stars and will be very dim in comparison
B) far from their parent stars and will be very dim in comparison
C) far from their parent stars and will be bright in comparison
D) close to their parent stars and will be bright in comparison

Question 73

Which of the following methods describes the transit method for detecting extrasolar planets?

A) regular changes in the positions of the parent stars with respect to more distant stars as they move across the sky
B) detection of Doppler shifts in the spectra of the parent stars
C) detection of brightness changes in a star as a planet passes in front of it
D) detection of reflected starlight

Question 74

NASA's Kepler mission, launched in 2009, is currently searching for exoplanets using which technique?

A) transit
B) Doppler
C) astrometry
D) gravitational lensing

Question 75

The decrease in infrared emission observed when a transiting exoplanet passes behind its parent star is a measure of the exoplanet's

A) mass
B) temperature
C) size
D) chemical composition

Question 76

When an exoplanet passes behind its parent star, we call this

A) an eclipse
B) a shadow event
C) a transit
D) an occultation

Question 77

According to our current theory of planet formation, can a Jupiter-like planet form from a rotating disk of dust and gas close to its parent star?

A) no, because the gases would be attracted to rocky terrestrial planets, forming atmospheres
B) yes, because we see Jupiter-like planets with small orbits around other stars
C) no, because it would be too hot for gases to condense
D) no, because there is no gas, only rock in the inner part of the disk

Question 78

What is the minimum mass of the exoplanet orbiting 70 Virginis if it has an orbital period of 116.69 days (p = 1.0082 x 10⁷ s) and an average orbital distance a = 7.18 x 10¹⁰ m. The star's orbital velocity is measured to be 291 m/s and its mass is 2.19 x 10³⁰ kg.

A) 2.73 x 10²⁷ kg
B) 1.42 x 10²⁸ kg
C) 3.16 x 10²⁹ kg
D) 4.67 x 10²⁶ kg

Question 79

Gravitational lensing is the process by which

A) a massive object magnifies and distorts the light from an object behind it
B) the wavelengths of light from a star are shifted as it moves about its center of mass
C) a planet passes in front of its parent star and blocks part of its light
D) a massive object accelerates another object that passes close to it

Question 80

Many of the extrasolar planetary systems discovered to date are

A) very different than our own solar system having terrestrial-size planets far from their parent stars
B) very similar to our own solar system with terrestrial-size planets close to their parent stars and Jovian-size planets far from their parent stars
C) identical to our own solar system with the same number and types of planets
D) very different than our own solar system having Jovian-size planets close to their parent stars