Stars & Galaxies When sun goes home behind the trees, and locks her shutters tight--- Then stars come out with silver keys to open up the night. Norma Farber

Table of Contents Units of Measurement Galaxies Life Cycle of a Star Sun

Dust & gas particles collect to form a nebula Dust & gas particles collect to form a nebula Temperatures begin to rise, at 10 million K the nebula begins to fuse together… Temperatures begin to rise, at 10 million K the nebula begins to fuse together… A main sequence star is created A main sequence star is created Birth of a Star

Growth of a Star Main sequence stars are fueled by hydrogen Main sequence stars are fueled by hydrogen They become a Giant or a Supergiant when all the fuel is gone They become a Giant or a Supergiant when all the fuel is gone As the structure of the Giant star collapses it becomes a white dwarf As the structure of the Giant star collapses it becomes a white dwarf As the structure of a Supergiant collapses it becomes a supernova As the structure of a Supergiant collapses it becomes a supernova

Death of a Star The white dwarf is the final stage of a Giant The white dwarf is the final stage of a Giant The neutron star or a black hole is the final stage of a Supergiant The neutron star or a black hole is the final stage of a Supergiant WIYN Image

What Color Am I? A star’s color is determined by how hot it is A star’s color is determined by how hot it is The color will range from orange-red (cool) The color will range from orange-red (cool) To blue-white (hot) To blue-white (hot)

What do you know? What is the name given to a newly formed star? What is the name given to a newly formed star? What gas fuels a star? What gas fuels a star? The final stage of a Giant is called… The final stage of a Giant is called… What determines a star’s color? What determines a star’s color?

Works Cited Bishop, David. Supernova Gallery. Latest Supernovae. February 11, Rochester Academy of Sciences. February 7, Bishop, David. Supernova Gallery. Latest Supernovae. February 11, Rochester Academy of Sciences. February 7, Kennedy, Dorothy and X.J. Kennedy. Talking Like the Rain. Boston: Little, Brown and Company, Kennedy, Dorothy and X.J. Kennedy. Talking Like the Rain. Boston: Little, Brown and Company, Sharp, Nigel, et. al. Far Red/Near Infrared Image of the Dumbbell Nebula. NOAO Image Gallery. January 2, National Optical Astronomy Observatory. February 7, Sharp, Nigel, et. al. Far Red/Near Infrared Image of the Dumbbell Nebula. NOAO Image Gallery. January 2, National Optical Astronomy Observatory. February 7, Barclay, Tom, et al. “Hertzsprung-Russell Diagrm,” SDSS Skyserver. Sloan Digital Sky Survey. February 28, Skyserver.fnal.gov/en/proj. Barclay, Tom, et al. “Hertzsprung-Russell Diagrm,” SDSS Skyserver. Sloan Digital Sky Survey. February 28, Skyserver.fnal.gov/en/proj. “EIT 304.” SOHO Exploring the Sun. February 28, Solar & Heliospheric Observatory. February 28, sohowww.nascom.nasa.gov/data/realtime/eit_304/512 “EIT 304.” SOHO Exploring the Sun. February 28, Solar & Heliospheric Observatory. February 28, sohowww.nascom.nasa.gov/data/realtime/eit_304/512

Astronomical Units of Measurement Taking measurements of space can be very difficult due to the vast spaces and distances. Taking measurements of space can be very difficult due to the vast spaces and distances. Specific terms are used to quantify these special distances. Specific terms are used to quantify these special distances. The brightness of stars are measured by absolute and apparent magnitude. The brightness of stars are measured by absolute and apparent magnitude.

Magnitude Stars may appear brighter because they are larger than other stars or because they are simply closer to earth. Stars may appear brighter because they are larger than other stars or because they are simply closer to earth. A star’s absolute magnitude is the measure of how much light the star actually gives off. A star’s absolute magnitude is the measure of how much light the star actually gives off. A measure of how much light we receive on earth from any given star is its apparent magnitude. A measure of how much light we receive on earth from any given star is its apparent magnitude.

Parsecs A star’s distance from earth is measured in parsecs. A star’s distance from earth is measured in parsecs. This is a measurement for a specific multiple of light-years (3.26). This is a measurement for a specific multiple of light-years (3.26). A light-year is the distance that light travels in one year. Light can travel at 300,000 km/s. So one light-year is equivalent to 9.5 trillion km. A light-year is the distance that light travels in one year. Light can travel at 300,000 km/s. So one light-year is equivalent to 9.5 trillion km.

Parallax The method for determining a star’s distance is to measure its parallax. The method for determining a star’s distance is to measure its parallax. An objects parallax is its apparent shift in position when viewed from two different places or locations. An objects parallax is its apparent shift in position when viewed from two different places or locations.

What do you Know? Which magnitude measures the brightness of light received on earth? Which magnitude measures the brightness of light received on earth? How many light-years are equivalent to one parsec? How many light-years are equivalent to one parsec? What method is used to measure the distance of stars? What method is used to measure the distance of stars?

Our Sun Our sun is an average star, because its yellowish light is in the middle of the color spectrum. Our sun is an average star, because its yellowish light is in the middle of the color spectrum. Usually two stars will orbit around each other. This is called a binary system. Our sun is a unique star, because it orbits by itself. Usually two stars will orbit around each other. This is called a binary system. Our sun is a unique star, because it orbits by itself.

Energy from the Sun The sun’s energy is produced in its core by hydrogen gases fusing into helium. The sun’s energy is produced in its core by hydrogen gases fusing into helium. The heat radiates out through the convection zone. The heat radiates out through the convection zone.

Layers of the Sun The sun has layers similar to our earth. The sun has layers similar to our earth. They are as follows: They are as follows: Core (innermost layer) Core (innermost layer) Radiation zone Radiation zone Convection zone Convection zone Photosphere Photosphere Chromosphere (outermost layer) Chromosphere (outermost layer)

Activity in the Chromosphere Because the sun is a ball of boiling and churning gas, its surface is constantly changing. Because the sun is a ball of boiling and churning gas, its surface is constantly changing.

Sunspots Sunspots are cooler areas of the surface. Sunspots are cooler areas of the surface.

Prominences Sometimes huge columns of gas arch across the sun’s surface. Sometimes huge columns of gas arch across the sun’s surface. These magnetic outbursts of energy are called prominences. These magnetic outbursts of energy are called prominences.

Solar Flares Solar flares occur when the gases near a sunspot suddenly erupt and shoot outward at high speed. Solar flares occur when the gases near a sunspot suddenly erupt and shoot outward at high speed. Sometimes the ultra-violet light or x-rays from these high energy particles interfere with radio signals here on earth. Sometimes the ultra-violet light or x-rays from these high energy particles interfere with radio signals here on earth.

What do you Know? How does the sun produce energy? How does the sun produce energy? Which layer is at the surface? Which layer is at the surface? What causes a sunspot? What causes a sunspot? Prominences are caused by what? Prominences are caused by what? Solar flares occur near what other surface feature? Solar flares occur near what other surface feature?

Galaxies A galaxy is a large group of stars, gas, and dust held together by gravity. A galaxy is a large group of stars, gas, and dust held together by gravity. There are three types of galaxies: There are three types of galaxies: Spiral Spiral Elliptical Elliptical Irregular Irregular

Spiral Galaxy A spiral galaxy has a central grouping of stars with arms projecting out into space. A spiral galaxy has a central grouping of stars with arms projecting out into space. Our Milky Way galaxy is a spiral galaxy. Our Milky Way galaxy is a spiral galaxy.

Elliptical Galaxy Elliptical galaxies resemble a football. They are large three- dimensional ellipses or ovals. Elliptical galaxies resemble a football. They are large three- dimensional ellipses or ovals.

Irregular Galaxy An irregular galaxy does not have a specific shape. An irregular galaxy does not have a specific shape. This category is used to group any galaxy that does not fit into the spiral or elliptical category. This category is used to group any galaxy that does not fit into the spiral or elliptical category.

Milky Way Galaxy The Milky Way is a spiral galaxy about 100,000 light years wide. The Milky Way is a spiral galaxy about 100,000 light years wide. Our solar system rotates around the center region of this galaxy. Our solar system rotates around the center region of this galaxy. This galaxy contains about 200 billion stars. This galaxy contains about 200 billion stars. The Milky Way is just one out of 30 galaxies that form a cluster. The Milky Way is just one out of 30 galaxies that form a cluster. This cluster is called the Local Group. This cluster is called the Local Group.

What do you Know? The Milky Way Galaxy is what shape? The Milky Way Galaxy is what shape? Which galaxy resembles a football? Which galaxy resembles a football? What features do Irregular Galaxies have? What features do Irregular Galaxies have? How many light-years across is the Milky Way Galaxy? How many light-years across is the Milky Way Galaxy?