Stars & GalaxiesStars & Galaxies

When sun goes home behind the trees,When sun goes home behind the trees,

and locks her shutters tight---and locks her shutters tight---

Then stars come out with silver keys to open Then stars come out with silver keys to open up the night.up the night.

Norma FarberNorma Farber

Table of ContentsTable of ContentsUnits of MeasurementGalaxiesLife Cycle of a StarSun

Dust & gas particles collect to form a Dust & gas particles collect to form a nebulanebula

Temperatures begin to rise, at 10 million K Temperatures begin to rise, at 10 million K the nebula begins to fuse together…the nebula begins to fuse together…

A main sequence star is createdA main sequence star is created

Birth of a StarBirth of a Star

Growth of a StarGrowth of a StarMain sequence stars are fueled by hydrogenMain sequence stars are fueled by hydrogenThey become a Giant or a Supergiant when They become a Giant or a Supergiant when

all the fuel is goneall the fuel is goneAs the structure of the Giant star collapses it As the structure of the Giant star collapses it

becomes a white dwarfbecomes a white dwarfAs the structure of a Supergiant collapses it As the structure of a Supergiant collapses it

becomes a supernovabecomes a supernova

Death of a StarDeath of a StarThe white dwarf is the final stage of a The white dwarf is the final stage of a

GiantGiantThe neutron star or a black hole is the The neutron star or a black hole is the

final stage of a Supergiantfinal stage of a Supergiant

WIYN Image

What Color Am I?What Color Am I?

A star’s color is determined by how hot it isA 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 do you know?What is the name given to a newly formed What is the name given to a newly formed

star?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 CitedWorks Cited Bishop, David. Supernova Gallery. Bishop, David. Supernova Gallery. Latest SupernovaeLatest Supernovae. February . February

11, 2003. Rochester Academy of Sciences. February 7, 2004. 11, 2003. Rochester Academy of Sciences. February 7, 2004. www.rochesterastronomy.org/snimages.www.rochesterastronomy.org/snimages.

Kennedy, Dorothy and X.J. Kennedy. Kennedy, Dorothy and X.J. Kennedy. Talking Like the RainTalking Like the Rain. Boston: . Boston: Little, Brown and Company, 1992.Little, Brown and Company, 1992.

Sharp, Nigel, et. al. Sharp, Nigel, et. al. Far Red/Near Infrared Image of the Dumbbell Far Red/Near Infrared Image of the Dumbbell NebulaNebula. NOAO Image Gallery. January 2, 2004. National Optical . NOAO Image Gallery. January 2, 2004. National Optical Astronomy Observatory. February 7, 2004. Astronomy Observatory. February 7, 2004. www.noao.edu/image_gallery/stars.html.www.noao.edu/image_gallery/stars.html.

Barclay, Tom, et al. “Hertzsprung-Russell Diagrm,” Barclay, Tom, et al. “Hertzsprung-Russell Diagrm,” SDSS SkyserverSDSS Skyserver. . Sloan Digital Sky Survey. February 28, 2004. Sloan Digital Sky Survey. February 28, 2004. Skyserver.fnal.gov/en/proj.Skyserver.fnal.gov/en/proj.

““EIT 304.” EIT 304.” SOHO Exploring the SunSOHO Exploring the Sun. February 28, 2004. Solar & . February 28, 2004. Solar & Heliospheric Observatory. February 28, 2004.Heliospheric Observatory. February 28, 2004.sohowww.nascom.nasa.gov/data/realtime/eit_304/512sohowww.nascom.nasa.gov/data/realtime/eit_304/512

Astronomical Units of Astronomical Units of MeasurementMeasurement

Taking measurements of space can be Taking measurements of space can be very difficult due to the vast spaces and very difficult due to the vast spaces and distances.distances.

Specific terms are used to quantify these Specific terms are used to quantify these special distances.special distances.

The brightness of stars are measured by The brightness of stars are measured by absolute and apparent magnitude.absolute and apparent magnitude.

MagnitudeMagnitudeStars may appear brighter because they Stars may appear brighter because they

are larger than other stars or because they are larger than other stars or because they are simply closer to earth.are simply closer to earth.

A star’s A star’s absolute magnitudeabsolute magnitude is the is the measure of how much light the star measure of how much light the star actually gives off.actually gives off.

A measure of how much light we receive A measure of how much light we receive on earth from any given star is its on earth from any given star is its apparent apparent magnitudemagnitude..

ParsecsParsecsA star’s distance from earth is measured in A star’s distance from earth is measured in

parsecs.parsecs.This is a measurement for a specific This is a measurement for a specific

multiple of light-years (3.26).multiple of light-years (3.26).A light-year is the distance that light A light-year is the distance that light

travels in one year. Light can travel at travels in one year. Light can travel at 300,000 km/s. So one light-year is 300,000 km/s. So one light-year is equivalent to 9.5 trillion km.equivalent to 9.5 trillion km.

ParallaxParallax

The method for determining a star’s The method for determining a star’s distance is to measure its parallax.distance is to measure its parallax.

An objects parallax is its apparent shift in An objects parallax is its apparent shift in position when viewed from two different position when viewed from two different places or locations.places or locations.

What do you Know?What do you Know?

Which magnitude measures the brightness Which magnitude measures the brightness of light received on earth?of light received on earth?

How many light-years are equivalent to How many light-years are equivalent to one parsec?one parsec?

What method is used to measure the What method is used to measure the distance of stars?distance of stars?

Our SunOur SunOur sun is an average star, because its Our sun is an average star, because its

yellowish light is in the middle of the color yellowish light is in the middle of the color spectrum.spectrum.

Usually two stars will orbit around each Usually two stars will orbit around each other. This is called a binary system. Our other. This is called a binary system. Our sun is a unique star, because it orbits by sun is a unique star, because it orbits by itself.itself.

Energy from the SunEnergy from the Sun

The sun’s energy is produced in its core The sun’s energy is produced in its core by hydrogen gases fusing into helium.by hydrogen gases fusing into helium.

The heat radiates out through the The heat radiates out through the convection zone.convection zone.

Layers of the SunLayers 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 zoneRadiation zoneConvection zoneConvection zonePhotospherePhotosphereChromosphere (outermost layer)Chromosphere (outermost layer)

Activity in the ChromosphereActivity in the Chromosphere Because the sun is a ball of boiling and churning gas, Because the sun is a ball of boiling and churning gas,

its surface is constantly changing.its surface is constantly changing.

SunspotsSunspots

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

ProminencesProminences

Sometimes huge columns of gas arch Sometimes huge columns of gas arch across the sun’s surface.across the sun’s surface.

These magnetic outbursts of energy are These magnetic outbursts of energy are called prominences.called prominences.

Solar FlaresSolar Flares

Solar flares occur when the gases near a Solar flares occur when the gases near a sunspot suddenly erupt and shoot outward sunspot suddenly erupt and shoot outward at high speed. at high speed.

Sometimes the ultra-violet light or x-rays Sometimes the ultra-violet light or x-rays from these high energy particles interfere from these high energy particles interfere with radio signals here on earth.with radio signals here on earth.

What do you Know?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 Solar flares occur near what other surface

feature?feature?

GalaxiesGalaxiesA galaxy is a large group of stars, gas, and A galaxy is a large group of stars, gas, and

dust held together by gravity.dust held together by gravity.There are three types of galaxies:There are three types of galaxies:

SpiralSpiralEllipticalElliptical IrregularIrregular

Spiral GalaxySpiral GalaxyA spiral galaxy has a central grouping of A spiral galaxy has a central grouping of

stars with arms projecting out into space.stars with arms projecting out into space.Our Milky Way galaxy is a spiral galaxy.Our Milky Way galaxy is a spiral galaxy.

Elliptical GalaxyElliptical Galaxy

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

Irregular GalaxyIrregular Galaxy

An irregular galaxy does not have a An irregular galaxy does not have a specific shape.specific shape.

This category is used to group any This category is used to group any galaxy that does not fit into the spiral galaxy that does not fit into the spiral or elliptical category.or elliptical category.

Milky Way GalaxyMilky Way GalaxyThe Milky Way is a spiral galaxy about The Milky Way is a spiral galaxy about

100,000 light years wide.100,000 light years wide.Our solar system rotates around the Our solar system rotates around the

center region of this galaxy.center region of this galaxy.This galaxy contains about 200 billion This galaxy contains about 200 billion

stars.stars.The Milky Way is just one out of 30 The Milky Way is just one out of 30

galaxies that form a cluster.galaxies that form a cluster.This cluster is called the Local Group.This cluster is called the Local Group.

What do you Know?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 How many light-years across is the Milky

Way Galaxy?Way Galaxy?