Sirius has a brightness through a blue filter of bB = 9.4 × 10-8 W/m2. What does this tell you about Sirius?

A) Sirius is a particularly bright star. B) Sirius is a particularly hot star. C) Sirius is a particularly cool star. D) This number, by itself, tells you nothing about Sirius. A) Sirius is a particularly bright star. B) Sirius is a particularly hot star. C) Sirius is a particularly cool star. D) This number, by itself, tells you nothing about Sirius.

The absolute magnitude of the Sun is +4.8 and its luminosity is 3.9 × 1026 watts. The luminosity of a star whose absolute magnitude is +3.8 is:

A) 2.9 × 1026 W. B) 9.8 × 1026 W. C) 3.9 × 1027 W. D) 1.6 × 1026 W. A) 2.9 × 1026 W. B) 9.8 × 1026 W. C) 3.9 × 1027 W. D) 1.6 × 1026 W.

Exam 17: The Nature of the Stars

The triple star system α Centauri has the largest known stellar parallax angle, namely 0.75 arcsec. How far is this star system from the Sun in parsecs? (Careful with units!)

(Multiple Choice)

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Question 81

Where are brown dwarfs located on the H-R diagram?

(Multiple Choice)

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Question 82

Sirius has a brightness through a blue filter of b_B = 9.4 × 10^-8 W/m². What does this tell you about Sirius?

(Multiple Choice)

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Question 83

On the basis of the Hertzsprung-Russell diagram (Figure 17-15a) and the mass-luminosity relationship for main-sequence stars (Figure 17-22), which of the following main-sequence stars have the greatest mass?

(Multiple Choice)

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Question 84

The spectrum of a particular star shows absorption lines due to calcium, iron, carbon, and titanium oxide. Which of these substances is classified as a "metal" by astronomers?

(Multiple Choice)

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Question 85

When the spectrum of a particular star is photographed and analyzed, it is found that the spectrum contains absorption bands of the metal hydrides methane (CH₄) and ammonia (NH₃). Based on this information, the star is:

(Multiple Choice)

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Question 86

A star with an apparent magnitude of m = +2.5 is at 100 pc from Earth. What is its absolute magnitude, M?

(Multiple Choice)

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Question 87

A particular star has an absolute magnitude of 0 and a spectral class similar to that of the Sun. Using Figure 17-18, how would this star be classified?

(Multiple Choice)

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Question 88

A star with a ratio of brightness b_V/b_B of 1.00 has a surface temperature of about: (See Figure 17-9.(in the text))

(Multiple Choice)

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Question 89

How do the characteristics of a K5V star compare to those of a K5II star? The K5II star:

(Multiple Choice)

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Question 90

The star γ Phoenecis has an apparent magnitude of 3.4 and an absolute magnitude of -4.6. The North Star (Polaris) has an apparent magnitude of 2.0 and an absolute magnitude of -4.6. Assuming that no light has been absorbed or scattered by interstellar dust, we can say for sure that:

(Multiple Choice)

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Question 91

The most straightforward way to measure the distance to a nearby star uses:

(Multiple Choice)

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Question 92

If a nearby star shows a parallax of 0.5 arcsec, what is its distance from Earth in light-years?

(Multiple Choice)

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Question 93

The ratio of the brightness of a star at two different colors, blue and visual-b_V/b_B-is a direct measure of what property of the star?

(Multiple Choice)

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Question 94

Suppose a star lying on the celestial equator has a proper motion, directed along the equator, equal to the rather large value of Barnard's star, namely 10 arcsec/yr. How long would it take this star to change its right ascension by 1 hour?

(Multiple Choice)

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Question 95

Using the Hertzsprung-Russell diagram in Figure 17-15a, determine which type of star has the following characteristics: surface temperature of 40,000 K and luminosity 100,000 times that of the Sun.

(Multiple Choice)

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Question 96

Vega is an A0 V star with a surface temperature of about 10,000 K. Use Figures 17-15a and 17-22 to estimate the mass of Vega.

(Multiple Choice)

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Question 97

Suppose we observe the light curve of a totally eclipsing binary like that in Figure 17-24b. The brightness falls gradually from magnitude 5 to magnitude 9 and remains there for 12 hours before increasing gradually to magnitude 5. Then, after a while, it drops gradually to magnitude 6, remains there for 8 hours, and returns to magnitude 5. What conclusion can be drawn from this light curve?

(Multiple Choice)

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Question 98

Which of the following statements is TRUE of the population of stars in our neighborhood?

(Multiple Choice)

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Question 99

The absolute magnitude of the Sun is +4.8 and its luminosity is 3.9 × 10²⁶ watts. The luminosity of a star whose absolute magnitude is +3.8 is:

(Multiple Choice)

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Question 100

Showing 81 - 100 of 113

Exam 17: The Nature of the Stars

The triple star system α Centauri has the largest known stellar parallax angle, namely 0.75 arcsec. How far is this star system from the Sun in parsecs? (Careful with units!)

Where are brown dwarfs located on the H-R diagram?

Sirius has a brightness through a blue filter of bB = 9.4 × 10-8 W/m2. What does this tell you about Sirius?

On the basis of the Hertzsprung-Russell diagram (Figure 17-15a) and the mass-luminosity relationship for main-sequence stars (Figure 17-22), which of the following main-sequence stars have the greatest mass?

The spectrum of a particular star shows absorption lines due to calcium, iron, carbon, and titanium oxide. Which of these substances is classified as a "metal" by astronomers?

When the spectrum of a particular star is photographed and analyzed, it is found that the spectrum contains absorption bands of the metal hydrides methane (CH4) and ammonia (NH3). Based on this information, the star is:

A star with an apparent magnitude of m = +2.5 is at 100 pc from Earth. What is its absolute magnitude, M?

A particular star has an absolute magnitude of 0 and a spectral class similar to that of the Sun. Using Figure 17-18, how would this star be classified?

A star with a ratio of brightness bV/bB of 1.00 has a surface temperature of about: (See Figure 17-9.(in the text))

How do the characteristics of a K5V star compare to those of a K5II star? The K5II star:

The star γ Phoenecis has an apparent magnitude of 3.4 and an absolute magnitude of -4.6. The North Star (Polaris) has an apparent magnitude of 2.0 and an absolute magnitude of -4.6. Assuming that no light has been absorbed or scattered by interstellar dust, we can say for sure that:

The most straightforward way to measure the distance to a nearby star uses:

If a nearby star shows a parallax of 0.5 arcsec, what is its distance from Earth in light-years?

The ratio of the brightness of a star at two different colors, blue and visual-bV/bB-is a direct measure of what property of the star?

Suppose a star lying on the celestial equator has a proper motion, directed along the equator, equal to the rather large value of Barnard's star, namely 10 arcsec/yr. How long would it take this star to change its right ascension by 1 hour?

Using the Hertzsprung-Russell diagram in Figure 17-15a, determine which type of star has the following characteristics: surface temperature of 40,000 K and luminosity 100,000 times that of the Sun.

Vega is an A0 V star with a surface temperature of about 10,000 K. Use Figures 17-15a and 17-22 to estimate the mass of Vega.

Which of the following statements is TRUE of the population of stars in our neighborhood?

The absolute magnitude of the Sun is +4.8 and its luminosity is 3.9 × 1026 watts. The luminosity of a star whose absolute magnitude is +3.8 is:

Astronomy and the Universe

Knowing the Heavens

Eclipses and the Motion of the Moon

Gravitation and the Waltz of the Planets

The Nature of Light

Optics and Telescopes

Comparative Planetology I: Our Solar System

Comparative Planetology II: the Origin of Our Solar System

The Living Earth

Our Barren Moon

Mercury, Venus, and Mars: Terrestrial, yet Unique

Jupiter and Saturn: Lords of the Planets

Jupiter and Saturns Satellites of Fire and Ice

Uranus, Neptune, Pluto, and the Kuiper Belt: Remote Worlds

Asteroids, Comets, and Impacts

Our Star, the Sun

The Birth of Stars

Stellar Evolution: on and After the Main Sequence

Stellar Evolution: The Death of Stars

Stellar Remnants: Neutron Stars and Black Holes

Our Galaxy

Galaxies

Quasars and Active Galaxies

Cosmology: The Origin and Evolution of the Universe

Exploring the Early Universe

The Search for Extraterrestrial Life

Filters

Sirius has a brightness through a blue filter of b_B = 9.4 × 10^-8 W/m². What does this tell you about Sirius?

When the spectrum of a particular star is photographed and analyzed, it is found that the spectrum contains absorption bands of the metal hydrides methane (CH₄) and ammonia (NH₃). Based on this information, the star is:

A star with a ratio of brightness b_V/b_B of 1.00 has a surface temperature of about: (See Figure 17-9.(in the text))

The ratio of the brightness of a star at two different colors, blue and visual-b_V/b_B-is a direct measure of what property of the star?

The absolute magnitude of the Sun is +4.8 and its luminosity is 3.9 × 10²⁶ watts. The luminosity of a star whose absolute magnitude is +3.8 is: