Q&A Hero

Q: In what range of masses are most stars found? A) 0.1 to 2 solar masses B) 1 to 3 solar masses C) 0.1 to 100 solar masses D) 0.01 to 100 solar masses E) Stars can have any mass.

Q: Stellar masses are measured directly by observations of the motions of A) eclipsing binary systems. B) spectroscopic binary systems. C) visual binary systems. D) All of the above can give us their masses. E) Stellar masses cannot be measured directly by any method.

Q: If we know the average separation and period of revolution for a binary system, we can then measure A) the actual sizes of the two stars. B) the total mass of the system. C) their absolute magnitudes. D) the actual mass of both individual stars. E) the actual luminosity of each star.

Q: Which type of binary can have their sizes measured directly by photometry? A) virtual B) visual C) eclipsing D) spectroscopic E) astrometric

Q: The Doppler shift is used to find A) eclipsing binaries. B) spectroscopic binaries. C) visual binaries. D) astrometric binaries. E) photometric binaries.

Q: Binary stars separated enough to be resolved in a telescope are called A) orbital binaries. B) visual binaries. C) spectroscopic binaries. D) astrometric binaries. E) line-of-sight binaries.

Q: A star near the lower right of the H-R diagram is likely to be A) red, with high luminosity. B) blue, with high luminosity. C) red, with low luminosity. D) hot, bright, and very large. E) yellow, with luminosity similar to our Sun's.

Q: Compared to the size of the Sun, stars of all types range from A) 0.1 to 10 solar radii. B) 0.5 to 50 solar radii. C) 0.01 to 1,000 solar radii. D) 0.08 to 8,000 solar radii. E) 0.001 to 50,000 solar radii.

Q: On the H-R diagram, red supergiants like Betelgeuse lie A) at the bottom left. B) at the bottom right. C) at the top left. D) at the top right. E) They can't be plotted, for they are not main sequence.

Q: On the H-R diagram, white dwarfs Sirius B and Procyon B lie A) at the top left. B) at the top right. C) close to the Sun, near the center. D) at the lower left. E) at the lower right.

Q: On the H-R diagram, the Sun lies A) at the top left. B) at the bottom left. C) at the bottom right. D) about the middle of the main sequence. E) at the top right.

Q: On the H-R diagram, the bright blue stars that dominate the naked-eye sky lie A) at the top right. B) at the top left. C) in the middle of the main sequence. D) at the lower right. E) at the lower left.

Q: In the H-R diagram, what are the two most important types of data plotted? A) absolute and apparent magnitudes B) apparent magnitudes and temperatures C) luminosities and masses D) sizes and temperatures E) spectral classes and absolute magnitudes

Q: The stars with masses comparable to our Sun's, but sizes like the Earth are A) red main sequence stars. B) white dwarfs. C) red giants. D) blue main sequence stars. E) neutron stars.

Q: The H-R diagram can plot A) temperature versus mass. B) radius versus luminosity. C) temperature versus luminosity. D) apparent magnitude versus spectral classes. E) radius versus mass.

Q: Compared to a type A0 star, a type A9 star is A) hotter. B) cooler. C) bluer. D) more massive. E) more luminous.

Q: In general, what can be said about type O and B stars compared to type K and M stars? A) They are hotter and older. B) They are cooler and older. C) They are hotter and younger. D) They are cooler and younger. E) They are neither hotter nor cooler, younger nor older.

Q: The star's color index is a quick way of determining its A) density. B) luminosity. C) mass. D) temperature. E) composition.

Q: Which of these binaries would appear most similar in color telescopically? A) F0V and G9III B) M1V and K9V C) A2Ia and F7Ia D) O2V and M4Ia E) F3IV and G8III

Q: What can be said with certainty about a red star and a blue star? A) The red star is more massive than the blue star. B) The blue star is hotter than the red star. C) The red star has a greater radial velocity than the blue star. D) The blue star has a greater proper motion than the red star. E) The red star is closer to Earth than the blue star.

Q: Which of these stars would be the hottest? A) A0 B) B0 C) G2 D) K9 E) M10

Q: What physical property of a star does the spectral type measure? A) density B) luminosity C) temperature D) mass E) composition

Q: Two stars both have parallaxes of 0.023", but star A has apparent magnitude +2.3, while star B is magnitude +7.3. Which statement is true? A) Star A must be ten times closer. B) Star B must be ten times more luminous. C) Nothing, since we do not know their absolute magnitudes. D) Star A is both 100 brighter and more luminous than star B. E) Star A is both 100 brighter and larger than star B.

Q: Without the strong nuclear force, the only element in the universe would be ________. Explain.

Q: What is happening to the mass of the Sun over time? Explain.

Q: In the proton-proton cycle, two positrons are produced. What more familiar particles are they similar to, and how do they differ?

Q: What is meant by "neutrino oscillation"?

Q: How are sunspots in the northern and southern hemispheres different?

Q: Describe how the sun's rotation is responsible for observed polarities of sunspots.

Q: A solar flare creates a radio disturbance on Earth a few minutes after going off, then again several days later. Explain.

Q: Describe the changes in the Sun from beginning to end of a sunspot cycle.

Q: If the corona is so hot, why do we have to wait for a total solar eclipse to see it?

Q: Describe evidence for convection in the photosphere.

Q: What happens in the radiative zone?

Q: Name the four forces of the universe from weakest to strongest.

Q: What happens to most of the solar neutrinos between the Sun's core and Earth?

Q: Both He3 and He4 are important in the proton-proton cycle. How are they different, and which comes first?

Q: Why is ten million degrees critical to the proton-proton cycle?

Q: How might a coronal mass ejection affect Earth?

Q: What are coronal holes?

Q: Relate sunspots and prominences.

Q: In Europe, what weather phenomenon coincided with the Maunder Minimum?

Q: The sunspot cycle is sometimes described as lasting 11 years, but others prefer to consider it as 22 years; explain the rationale.

Q: Are sunspots really dark and cool?

Q: Two pairs of sunspots appear similar, but if one was observed in 1990, and the next in 2002, we would note what difference?

Q: What is the best time to see the corona? Why is it so faint, if it is so hot?

Q: Apply Wein's law to explain the corona's main energy release.

Q: Why are different spectral lines, such as helium, more visible in the corona than in the Sun's normal absorption spectrum?

Q: Describe the temperature change in the transition zone.

Q: Why is it hard to observe the chromosphere?

Q: What are the main constituents of the solar wind? Which travel faster?

Q: Why is the bright yellow disk of the Sun, the photosphere, cooler than the areas both above and below it?

Q: How is energy transfer from the solar interior to surface similar to a process in Earth's atmosphere?

Q: How large are granules, and how long do they last?

Q: What do sunspots tell us about the Sun's rotation rate?

Q: Define the solar constant.

Q: What other solar system body has an average density similar to the Sun's? Why?

Q: At its current rate of consuming hydrogen, the Sun can stably shine for ________.

Q: The solar neutrino problem was solved when it was discovered that neutrinos ________ during the time they take to reach the Earth.

Q: The only particle we can directly observe coming out of the Sun's core is the ________.

Q: The gamma rays created in the Sun's core move freely through the ________ zone.

Q: Fusion depends upon the ________ nuclear force getting the protons to stick together.

Q: Nuclear ________ explains the Sun's immense and sustained energy output.

Q: The major product of the fusion of 4 protons in the Sun's core is a ________ nucleus.

Q: The Maunder Minimum refers to a period of sustained solar ________ from 1645 until about 1715.

Q: During a period of high solar activity, most sunspots lie near the Sun's ________.

Q: Flares and prominences are more numerous during ________.

Q: A solar ________ is a sudden, violent disruption around sunspots, releasing a tremendous amount of energy in almost all wavelengths.

Q: The ________-year solar cycle is characterized by a variation in the number of sunspots through a reversal of the magnetic polarity of the Sun as a whole.

Q: The strongest magnetic fields in the photosphere lie near ________.

Q: A loop or sheet of gas hanging above an active region of the Sun is a ________, often striking along the limb during total eclipses.

Q: Sunspots are ________ poles in the photosphere.

Q: While the photosphere produces chiefly visible light, most coronal energy is in the form of ________.

Q: The ________ blows out of the coronal holes.

Q: The high temperature of the corona is directly responsible for the ________.

Q: Compared to the underlying photosphere and chromosphere, the corona is ________ in temperature.

Q: The corona can only be glimpsed from Earth during a ________.

Q: Stellar spectra tell us that ________ is the second most abundant element in the Sun.

Q: The ________ transport subsurface material from the Sun's equator to its poles and back at a depth far below the convection zone.

Q: The pattern of hot convective cells rising in the photosphere is called ________.