A glowing ball of gas held together by its own gravity and powered by nuclear fusion in its core.
What is a star (or the Sun)?
100
Any star with radius comparable to, or smaller than, that of the Sun.
What is a dwarf?
100
A system of ranking stars by apparent brightness, developed by the Greek astronomer Hipparchus.
What is the magnitude scale?
100
The brightness that a star appears to have, as measured by an observer on Earth.
What is apparent brightness?
200
The visible surface of the Sun, lying just above the uppermost layer of the Sun's interior, and just below the chromosphere.
What is the photosphere?
200
A classification scheme that groups stars according to the width of their spectral lines.
What is luminosity class?
200
A star with a radius between 10 and 100 times that of the Sun?
What is a giant?
200
The apparent brightness of a star, expressed using the magnitude scale.
What is apparent magnitude?
200
One of the basic properties used to characterize stars and defined as the total energy radiated by each star each second, at all wavelengths.
What is luminosity?
300
The Sun's lower atmosphere, lying just above the visible atmosphere.
What is the chromosphere?
300
A plot of luminosity against temperature (or spectral class) for a group of stars.
What is H-R diagram?
300
A dwarf star with such a sufficiently high surface temperature that it glows white.
What is a white dwarf?
300
The apparent magnitude a star would have if it were placed at a standard distance of 10 parsecs from Earth.
What is absolute magnitude?
300
Method of determining the distance to a star by measuring its temperature and then determining its absolute brightness by comparing it with a standard H-R diagram.
What is spectroscopic parallax?
400
The region of rapid temperature increases that separates the Sun's chromosphere from the corona.
What is the transition zone?
400
The variation in brightness of a star with time.
What is a light curve?
400
A star with radius between 100 and 1000 times that of the Sun.
What is a super giant?
400
The distance at which a star must lie in order for its measured parallax to be exactly 1 arc second.
What is parsec?
400
The parallax of an object with a distance of 5 parsecs?
What is .20?
500
Region of the Sun's interior where extremely high temperatures guarantee that the gas is completely ionized.
What is the radiation zone?
500
A well defined band on the Hertzsprung-Russell diagram on which most stars are found, running from the top left of the diagram to the bottom right.
What is the main sequence?
500
Name the 5 basic physical stellar quantities.
What are: luminosity, temperature, chemical composition, size, and mass?
500
The formula for distance from the Sun in parsecs.
What is distance(in parsecs)= 1/ parallax (in arcseconds)?
500
The parallax of an object with a distance of 25 parsecs?