_____ is a clue to a star's temperature
________ stars can be used to determine stellar mass
The ____________ stars have the largest parallax angles, while those of distant stars are too small to measure.
how big it is, how hot it is, and how far away it is.
Three Factors that control the apparrent brightness of a star as seen from earth?
_________ shows the relationship between the absolute magnitud and temperature of stars.
When the core of a protostar has reached at least ______________ K, pressure within is so great that fusion of hydrogen begins, and a star is born.
All stars, regardless of their size, eventually run out of fuel and collapse due to __________.
Stars like the sun begin as a ___________, spend much of their lives as __________ stars, become red giants, planetary nebulae, white dwarfs, and finally , black dwarfs.
milky way, spiral, 100,000, 10,000
The ___________ is a large ________ galaxy whose disk is about _____________ light-years wide and about _______ light-years thick at the nucleus.
In addition to size and shape, one of the major differences among different types of galaxies is the ____ of their stars.
The _______ shifts of distant galaxies indicate that the universe is ________.
big bang theory, ball, 13.7
______ states that at one time, the entire universe was confined to a dense, hot, supermassive _____. Then about _____ billion years ago, a violent explosion occurred, hurling this material in all directions.
How much a star wobbles is related to its ______.
brightness of a star
How bright a star appears is _____.
how bright a star actually is ______.
the ________ the star the brighter the star.
age; irregular stars
age; spiral stars
age; elliptical stars
shape; elliptical stars
unit to express stellar distance
milk way; age
the outward expansion will follow, expand forever
The future of the universe; 2 paths
More ______ the closer they come together
surface temperature related to its______
color depends on the ________.
most stuff, big ____
White dwarfs final stage of evolution when they collapse to very small _____.
white dwarf is extremely ______.
shite dwarf is made up of _________ matter
the sun begins as a ___________.
Order of sun begins _________
smallest white dwarf is ________ massive gravity so it "squeezes more tightly.
_________ stars are thought to be remnants of supernova events. pea size sample 100 million tons.
density of the nucleus of the atom
the density of neutron stars=
supernova, neutron, magnetic
during this the outer layer of a star is ejected. forms a visible nebula. and the core becomes a ________ star. Has a strong _______ field.
radio waves , found in the _________ nebula-during the 1970s is undoubtedly the remains of the supernova of 1054.
________ holes are the most massive stars that produce even more dense remnants after a supernova. Gravity prevents its escape from anything.
________ dwarf star is a star that has exausted most or all of its nuclear fuel and has collapsed to a very small size, believed to be near its final stage of evolution.
_____ sequence star , once fusion begins a star becomes this.
Where it starts on the sequence is based on the its __________ mass
more massive stars begin as large _____ stars
less massive stars begin somewhere _______ the main sequence
stars _______ at different rates
massive stars us fuel ______.
_______ stars use fuel slowly an exist for perhaps hundreds of billions of years
hydrogen, helium, outward
as _________ fuses into _______________ in the interior, the fusion migrates ______
surface cools and becomes _______
star spends almost ______ % of its life as a main-sequence star
an apparent group of stars originally named for the mythical characters; the sky is presently divided into 88 constellations
a star whose brightness varies periodically because it expands and contracts a type of pulsating star.
a star that explosively increases in brightness
one of two stars revolving around a common center of mass under their mutual gravitational attraction
a group of stars, dust, and gases held together by gravity.
a system of galaxies containing from several to thousands of member galaxies.
a law that states that the galaxies are retreating from the milky way at a speed that is proportional to their distance.
a very large, very bright red giant star
a large, cool star of high luminosity; a star occupying the upper- right portion of the H-R diagram
cloud of gas and dust in space
a collapsing cloud of gas and dust destined to become a star; a developing star not yet hot enough to engage in nuclear fusion.
made mostly of dust, reflects light of a nearby star
far from any stars so they do not reflect or absorb energy from an stars, not dense has as much matter as a star/planet system.
protostar glows _____
if cool then____
if hot then _____
if medium temp ____
The difference in the brightness of two stars with the same surface temperature is attributable to their ____.
temperature and absolute magnitude
A Hertzsprung-Russell (H-R) diagram shows the relationship between ____.
Which main-sequence stars are the most massive?
According to Figure 25-1, which main-sequence stars are brightest?
According to Figure 25-1, the sun has an absolute magnitude of ____.
a protostar reaches a temperature high enough for nuclear fusion to begin
A star is said to be born when ____.
In the Milky Way, the most abundant gas in emission nebulae is ____.
Which stars are composed of matter in which electrons have combined with protons?
About 60 percent of all known galaxies are classified as ____.
Some stars, called ____________________, get brighter and fainter in a regular pattern
A(n) ____________________ is a developing star not yet hot enough to engage in nuclear fusion.
In addition to size and shape, one of the major differences among galaxies is the ____________________ of their stars.
A(n) ____________________ galaxy is a type of galaxy that lacks symmetry.
The apparent change in wavelength of radiation caused by the relative motions of the source and the observer is called the ____________________.
round or oval
30 percent of galaxies are ____ galaxies