Stars Flashcards
Solar Nebula
a gaseous cloud, a giant cloud of dust and gas in space
Hertzsprung-Russell Diagram
illustrates the relationship between the absolute magnitude and the surface temperature of stars
White dwarf
a small, hot dim star that is the leftover center of an old star
Luminosity
the total amount of energy a star gives off each second
Nuclear fusion
a process that occurs when extremely high temperature and pressure cause less-massive atomic nuclei to combine to form more-massive nuclei and release enormous amounts of energy
Absolute magnitude
the brightness of a star if it were seen from a standard distance
Supernova
a star that has such a tremendous explosion that it blows itself apart
Apparent magnitude
brightness of a star as seen from Earth
Black hole
an object so massive and dense that even light cannot escape its gravity
Galaxy
a collection of stars, dust and gas bound together by gravity
Planetary Nebula
a cloud of gas that forms around a sun-like star that is dying
Protostar
shrinking, spinning region that begins to flatten into a disk that has a central concentration of matter
Star
a ball of gases that gives off a tremendous amount of electromagnetic energy. This energy comes from nuclear fusion.
Main-sequence star
about 90% of stars, they fuse hydrogen atoms to form helium atoms in their cores
Neutron Star
a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons
Identify the major factor that controls a star’s evolution and lifespan.
the total mass
List the two major elements found in stars
hydrogen + helium
During the beginning of a star’s life in nuclear fusion what element is created
helium
Describe what is happening during the stellar nebula stage.
In the stellar nebula stage, a cloud of gas and dust is where a star begins. The gravitational force increases as the mass of an object increases or as the distance between two objects decreases. As more particles come together, regions of dense matter begin to build up within the cloud. Depending on the amount of gas and dust, the star may become massive or average. That defines the two evolution of stars.
Identify when the birth of a star begins
Onset of fusion
Explain what is happening during the main sequence stage of a star.
Nuclear fusion occurs faster in more massive stars than less massive stars and hydrogen is fused into helium. When this happens, the star begins to move out of the main-sequence stage and about 90% of the stars are main sequence stars.
Explain why stars leave the main sequence stage.
Stars start to lose their main fuel, hydrogen, depending on their initial mass. The loss of energy causes the main sequence’s gravitational collapse to resume.
Define nuclear fusion.
A process that occurs when extremely high temperature and pressure cause less-massive atomic nuclei to combine to form more-massive nuclei an in this process, release enormous amounts of energy.
Explain what happens to helium and the outer layers of a star in the planetary nebula stage
The star’s outer layers continue to expand, the core contracts inward, and helium atoms in the core fuse together to form carbon. The star will now begin to shed its outer layers as a diffuse cloud.
Why do stars become giants or supergiants?
The fusion of hydrogen to form helium changes the interior composition of a star, which turn results in changes in its temperature, luminosity, and radius.
What is a supernova?
A supernova is the big luminous explosion of a star.
What happens to the star after a supernova?
It becomes a neutron star
What is a white dwarf?
A white dwarf is a small, dim star that is the leftover center of an old star. Hot, extremely dense core of matter. Gravity causes the remaining matter in the star to collapse inward. The matter collapses until it cannot be pressed further together.
List the star’s color in the correct order from hottest to coldest.
Blue, white, yellow, orange, red
Identify the 3 types of galaxies. What galaxy is Earth in?
Elliptical galaxy, irregular galaxy, spiral galaxy, milky way galaxy (the one earth is in)
Identify the two variables used to identify stars on the H-R diagram.
Luminosity and temperature
Identify the 4 major classifications of stars.
Main sequence, blue giants, red supergiants, red giants
Differentiate between a red giants and blue giants
Blue giant: they are younger, higher temperature, eventually becomes a red giant, burns mostly hydrogen
Red giant: older, lower temperature, may become a blue giant if its core gets hot enough and the outer gases escape, burns helium
List the average star’s stages in correct order.
Stellar nebula, Birth of a star, Main sequence, Giant star, Planetary nebula, White dwarf
List the massive star’s stages in correct order.
Stellar nebula, Birth of a Star, Main sequence, Super Giant star, Supernova, Black hole/neutron star
Scientists believe that the Solar Nebula Theory is the best theory that is used to describe how our solar system was formed. In one paragraph explain this theory.
A cloud of gas and dust began to collapse by gravity begins to spin faster because of the angular momentum conservation. The collapsing, spinning nebula begins to flatten into a pancake shape with a bulge at the center. As the nebular collapses further, rotating cloud cause local regions to begin to contract gravitationally. These regions become the sun and the planets as well as moon and others in the solar system.
