Chapter 8 Flashcards
Based on measuring distances to stars, select all of the correct statements from the following list.
There are about 20,000 parsecs in an AU.
Determination of distance by observing parallax works mostly for nearby stars.
To determine the luminosity of a star, you must first know the distance.
Most stars have measurable parallax shifts.
For the distance to far stars, it is necessary to use spectroscopic parallax.
A parsec is the distance that light travels in one second.
There are no other stars within a parsec of the sun.
Determination of distance by observing parallax works mostly for nearby stars.
To determine the luminosity of a star, you must first know the distance.
For the distance to far stars, it is necessary to use spectroscopic parallax.
There are no other stars within a parsec of the sun.
Based on the intrinsic brightness of stars, select all of the correct statements from the following list.
To know how bright a star really is, you must first know its distance.
A star’s luminosity depends on its distance.
A star closer than 10 parsecs will have a brighter apparent magnitude than absolute magnitude.
Apparent magnitude is a measurement of intrinsic brightness.
The absolute magnitude of a star is the same as its apparent magnitude at a distance of 10 parsecs.
There are stars with greater and lesser magnitude than the sun.
Luminosity is determined from apparent magnitude.
To know how bright a star really is, you must first know its distance.
A star closer than 10 parsecs will have a brighter apparent magnitude than absolute magnitude.
The absolute magnitude of a star is the same as its apparent magnitude at a distance of 10 parsecs.
There are stars with greater and lesser magnitude than the sun.
Based on the diameters of stars, select all of the correct statements from the following list.
Giant and supergiant stars are always bright.
More massive stars are hotter and brighter.
The H-R diagram is a plot of sizes vs. temperatures of stars.
Both absolute and apparent magnitude are plotted on the H-R diagram.
Big stars have very sharp spectral lines.
The H-R diagram can be used to determine the distance to very distant stars.
All small stars are cool.
Giant and supergiant stars are always bright.
More massive stars are hotter and brighter.
Big stars have very sharp spectral lines.
The H-R diagram can be used to determine the distance to very distant stars.
Based on the masses of stars, select all of the correct statements from the following list.
White dwarf stars are very dense.
Most main sequence stars are of similar mass to the sun.
All stars follow the mass-luminosity relation.
Brighter main sequence stars are more massive.
Giant and supergiant stars tend to be dense.
Some stars are thinner than air.
Direct determination of mass can only be done for stars in binary systems.
White dwarf stars are very dense.
Brighter main sequence stars are more massive.
Some stars are thinner than air.
Direct determination of mass can only be done for stars in binary systems.
Based on a survey of the stars, select all of the correct statements from the following list.
White dwarfs are very rare.
Most of the sun’s neighbors are brighter than the sun.
More massive stars are rare.
Bright stars are common.
There are no giants or supergiants in the sun’s neighborhood.
Most of the sun’s neighbors are of low mass.
There are no white dwarfs in the sun’s neighborhood
More massive stars are rare.
There are no giants or supergiants in the sun’s neighborhood.
Most of the sun’s neighbors are of low mass.
If a star has a parallax of 1 second of arc, what is its distance in parsecs?
1
If a star has a parallax of 1 second of arc, what is its distance in light-years?
3,26
If a star is 10 pc away, what is its parallax in seconds of arc?
0.1
If a main-sequence star has a luminosity of 2,000 L, what is its spectral type?
spectral type B1
In the table above, which star is brightest in apparent magnitude?
star a
In the table above, which star is most luminous in absolute magnitude?
star c
In the table above, which star is largest?
star c
In the table above, which star is farthest away?
star d
Even through a telescope, a star appears to be a single star but through the spectroscope it shows a pattern of two absorption lines for each of the lines in the spectrum of a star like our sun. For each member of the pattern, one line, which is somewhat stronger than the other, is at a shorter wavelength. The weaker is at a somewhat longer wavelength. Over the 5 days the two lines merge into one then separate during the next 5 days back to the former maximum difference. However, now the stronger line is at a longer wavelength. From this evidence, there are actually ____ stars which orbit one another once every _____ days.
2;20
Even through a telescope, a star appears to be a single star but through the spectroscope it shows two absorption lines where a star like our Sun shows one. One line, which is somewhat stronger than the other, is at a shorter wavelength. Over the 5 days the two lines merge into one then separate during the next 5 days back to the former maximum difference. However, now the stronger line is at a longer wavelength. When the two lines combine in wavelength, the apparent single star dips in brightness. From this evidence, there are actually ______ stars which orbit one another in an orbit ______ to the direction from the stars to us.
2;edge-on
Determine the temperature of a star based on the following spectrum: medium-strength Balmer lines and strong helium lines.
about 18,000 K to 25,000 K
Determine the temperature of a star based on the following spectrum: weak Balmer lines and medium-strength ionized calcium lines.
about 5,000 K to 6,000 K
Determine the temperature of a star based on the following spectrum: strong Balmer lines.
about 9,000 K to 12,000 K
Determine the temperature of a star based on the following spectrum: very strong TiO bands.
about 2,000 K to 3,500 K
Use the table to find the spectral type of a star which has very weak Balmer lines and strong ionized calcium lines.
Spectral type K
Use the table to find the spectral type of a star which has medium-strength Balmer lines and strong helium lines.
Spectral type B
Use the table to find the spectral type of a star which has very weak Balmer lines and strong ionized helium lines.
Spectral type O
