illustrates the relationship that exists between the average surface temperature of stars and how bright they would be if they were all the same distance away
a measure of how much energy leaves a star in a certain period of time; measured in lumins
main sequence star, 6000 C, 10 billion years old
star colors from hottest to coldest
blue, white, yellow, red
a cloud of interstellar gas (mostly hydrogen) and dust (mostly silicon and carbon). the dust is pulled together by gravity and begins to spin. the increase in speed of the spin heats up the mass into a protostar, which continues to grow.
main sequence star
nuclear fusion of hydrogen atoms into helium atoms releases large amounts of energy. the star reaches hydrostatic equilibrium and becomes a main sequence star
the process of light nuclei combining to form heavier nuclei
the forces of gravity trying to collapse the star are balanced out by the energy released from the fusion reactions trying to blow the star apart
the hydrostatic equilibrium is lost as the hydrogen supply in the core of the star become depleated. the outer layers expand, glow red, and luminosity increases. (larger but less massive than main sequence stars)
white dwarf (from red giant)
the red giant has converted all the helium into carbon, its core collapses into a white dwarf, and the outer layers are expelled into planetary nebula. no furthur nuclear reactions take place and eventually no light is seen.
neutron star (from red supergiant)
nuclear fusion continues in this more massive star. when it finally does stop, the star will explode into a supernova and its core will collapes into a dense neutron star.
creating heavier elements from lighter elements in stars
very dense matter in a state where the pressure no longer depends on temperature due to quantum mechanical effects
rotating neutrons stars with strong magnetic fields