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.
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.
_________ stars are thought to be remnants of supernova events. pea size sample 100 million tons.
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.
hydrogen, helium, outward
as _________ fuses into _______________ in the interior, the fusion migrates ______
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.
one of two stars revolving around a common center of mass under their mutual gravitational attraction
a law that states that the galaxies are retreating from the milky way at a speed that is proportional to their distance.
a large, cool star of high luminosity; a star occupying the upper- right portion of the H-R diagram
a collapsing cloud of gas and dust destined to become a star; a developing star not yet hot enough to engage in nuclear fusion.
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.
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 ____.
a protostar reaches a temperature high enough for nuclear fusion to begin
A star is said to be born when ____.
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.
The apparent change in wavelength of radiation caused by the relative motions of the source and the observer is called the ____________________.