Chapter 7 Flashcards
Based on the solar atmosphere and outer layers of the sun, select all of the correct statements from the following list.
The temperature of the corona is millions of degrees.
The photosphere is the outermost layer of the sun.
Spicules and filaments are found in the solar corona.
The solar wind is ionized gas streaming away from the sun.
The chromosphere is the visible surface of the sun.
Helioseismology is the study of “sunquakes.”
Granulation is caused by convection.
The temperature of the corona is millions of degrees.
The solar wind is ionized gas streaming away from the sun.
Granulation is caused by convection.
Based on nuclear fusion in the sun, select all of the correct statements from the following list.
Neutrinos oscillate among three different types.
For nuclei to combine, temperatures must be very high.
Due to the required temperatures, fusion occurs only in the core of the sun.
During the proton-proton chain, helium is made into hydrogen.
Gamma rays produced by fusion make it to the solar surface much faster than neutrinos.
The number of neutrinos observed to be coming from the sun is the amount we expect.
Since we observed light from the photosphere, some fusion must be occurring there.
Neutrinos oscillate among three different types.
For nuclei to combine, temperatures must be very high.
Due to the required temperatures, fusion occurs only in the core of the sun.
The radius of the sun is 0.7 million km. What percentage of the radius is taken up by the chromosphere which is about 2,100 km deep?
0.3%
What evidence do we have that the granulation seen on the sun’s surface is caused by convection?
The bright centers of granules are hotter than their dark boundaries and Doppler measurements indicate that the centers are rising and edges are sinking.
Which layer of the sun’s atmosphere contains the cooler low-density gas responsible for absorption lines in the sun’s spectrum?
photosphere
Which of the following is true about granules and supergranules?
They are both due to convection cells in layers below.
This diagram explains the structure of solar granules. Why is the center of a granule brighter than its edges?
The temperature is higher at the center.
What is revealed by observing the sun at a very narrow range of wavelengths within the 656-nm hydrogen alpha line?
the structure of the chromosphere
The sun’s atmospheric layers are all less dense than its interior. Based on this figure, which layer of the sun is responsible for the absorption lines in the solar spectrum?
photosphere
What are the general trends in temperature and density from the photosphere to the chromosphere to the corona?
The temperature increases and density decreases.
What physical property of the sun is responsible for “limb darkening”?
The lower photosphere is hotter than the upper photosphere.
The spectrum of the corona has bright spectral lines of highly ionized elements. What does this reveal?
The corona is a very hot, low-density gas.
What heats the chromosphere and corona to high temperatures?
fluctuating magnetic fields from below that transport energy outward
How are astronomers able to explore the layers of the sun below the photosphere?
They do this by measuring and modeling the modes of vibration of the sun’s surface.
What is responsible for the sun’s surface and atmospheric activity?
the sun’s magnetic field
Each of these frames shows the migration (due mostly to solar rotation) of sunspots across the face of the sun with the earliest sketch at the top. If the north pole of the sun is at the top of each frame, in which direction does the sun rotate?
counterclockwise when viewed from above the sun’s north pole
What is the source of the sun’s changing magnetic field?
the differential rotation of the sun and convection beneath the photosphere
What evidence do we have that sunspots are magnetic?
The spectral lines of sunspots are split by the Zeeman Effect and observations at far ultraviolet show material arched above the sun’s surface from one sunspot to another.
What does a Maunder butterfly diagram show?
During the 11-year sunspot cycle, the spots begin at high latitude and then form progressively closer to the equator.
How constant is the solar constant? That is, by how much has the solar constant of 1,360 joules per square meter per second been observed to vary over days or weeks?
about 0.1%
How does the sun maintain its energy output?
fusion of hydrogen nuclei
Why does nuclear fusion require high temperatures?
All of these choices are correct.
Based on this figure, which atomic element has the greatest binding energy per nuclear particle?
iron
What happens to the neutrinos that are produced in the proton-proton chain?
they head out of the sun at nearly the speed of light
Which layer is considered the visible surface of the sun?
The discovery that neutrinos oscillate between three different types
Which layer is considered the visible surface of the sun?
the photosphere
