Quiz 11 - Chapters 21 & 22
Our solar system has 8 planets orbiting the Sun. Based on the discoveries of exoplanets so far, what can we say about a star with 8 planets?
Even though planets were only discovered starting in 1995, so we can't yet find planets that take centuries to go around their star, we already know other stars with 8 planets and we are likely to find more
The star now called Kepler-444 is 11 billion years old (much older than the Sun) and has five planets orbiting close to it. What has this system taught astronomers about the history of star formation?
If such an old star has planets close to it, where it's really warm, those planets must be made of heavier elements. So heavier elements must have formed before the time this star formed.
Which of the following types of stars will spend the longest time (the greatest number of years) on the main sequence?
K
Which of the following is a reason that astronomers have not found giant planets with the orbit of Neptune around other stars?
Neptune takes 165 years to go around the Sun; getting information about just one cycle of such a planet's orbit around another star would take astronomers 165 years
Which of the following stages will our own Sun go through in the future:
all of these
The event in the life of a star that begins its expansion into a giant is
almost all the hydrogen in its core that was hot enough for fusion has been turned into helium
If stars with masses like our Sun's cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?
heavier elements are made in the cores of significantly more massive stars than the Sun, which can get hotter in the middle
If you trace back the history of a carbon atom in your little finger through all of cosmic history, where did this atom most likely originate?
it was fused from 3 helium nuclei in the core of a red giant star long before the Sun existed
The closest star to the Sun, Proxima Centauri, was recently found to have a planet in its habitable zone. Proxima Centauri is a main sequence star with spectral type M. How would its habitable zone differ from the habitable zone of our Sun?
it would be significantly closer to Proxima Centauri than ours is to the Sun
The big surprise about the first planet discovered around another regular star was that it
orbited so close to its star it took only 4 days to go around
The telescope that allowed astronomers to discover most of the planets found with the transit method was called
the Kepler mission
As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?
the O and B type stars
With our current techniques, astronomers can typically only measure the minimum mass of a planet orbiting another star. To know the precise mass of the planet, they must also be able to determine
the angle at which the planet's orbit is tilted relative to us
Which of the following are the small regions that are the embryos of stars (where individual stars are most likely to be born)?
the cores within the clumps of molecular clouds
On an H-R diagram of a cluster of stars, which characteristic of the diagram do astronomers use as a good indicator of the cluster's age?
the point on the main sequence where stars begin to "turn off" -- to move toward the red giant region
When stars become giants, which of the following does Not usually happen?
their mass grows significantly as they incorporate planets and interstellar matter near the star
Which of the following statements about open clusters of stars is False?
they typically contain more mass than any other type of cluster
Astronomers studying regions like the Orion Giant Molecular Cloud have observed that a wave of star formation can move through them over many millions of years. What sustains such a wave of star formation in a giant molecular cloud?
when massive stars form, their ultraviolet radiation and later their final explosions compress the gas in the cloud and cause a new group of stars to form
