STARS. Instructions Students will underline the portions of the PowerPoint that are underlined.

STARS

Instructions

• Students will underline the portions of the PowerPoint that are underlined.

A Nuclear FurnaceA Nuclear Furnace

1. A star is like a gigantic nuclear 1. A star is like a gigantic nuclear furnace. furnace.

2. The nuclear reactions inside convert 2. The nuclear reactions inside convert hydrogen into helium by means of a hydrogen into helium by means of a process known as fusion. process known as fusion.

3. It is this nuclear reaction that gives 3. It is this nuclear reaction that gives a star its energy. a star its energy.

Classifying StarsClassifying Stars

Scientists classify stars by:Scientists classify stars by:

1.1.TemperatureTemperature

2.2.BrightnessBrightness

1. The color of a star tells us about its 1. The color of a star tells us about its temperaturetemperature..

Blue stars are the hottestBlue stars are the hottest, 7500°C- , 7500°C- 30,000°C.30,000°C.

Red stars are the coolestRed stars are the coolest, less than , less than 3500°C. 3500°C.

Our sun is yellow in color, in the Our sun is yellow in color, in the middle of the temperature scale,middle of the temperature scale, from 5000°C-7500°C. from 5000°C-7500°C.

Star TemperatureStar Temperature

CONSTELLATION ORION

Betelgeuse-

Red Star- Coolest

Rigel-

Blue Star-Hottest

Brightness or MagnitudeBrightness or Magnitude

1.1. Stars are also classified by their brightness.Stars are also classified by their brightness.

2. The brightness of a star as seen from Earth is 2. The brightness of a star as seen from Earth is called apparent magnitude.called apparent magnitude.

3. The actual brightness of a star is called absolute 3. The actual brightness of a star is called absolute magnitudemagnitude..

Example: The SUN has an absolute magnitude Example: The SUN has an absolute magnitude of 4.8 when compared to the other stars. The of 4.8 when compared to the other stars. The SUN has an apparent magnitude of -26.8 SUN has an apparent magnitude of -26.8 because it is so close. because it is so close.

Another Example of Another Example of absolute and apparent absolute and apparent

magnitude.magnitude.

Which light is brighter, A or B?

AB

Light A is brighter than light B.Light A is brighter than light B. We see the apparent magnitude of the lights We see the apparent magnitude of the lights

(how they look to us) (how they look to us) If lights A and B were next to each other they If lights A and B were next to each other they

would look the same because the two lights are would look the same because the two lights are exactly the same.exactly the same.

Their absolute magnitude is the same.Their absolute magnitude is the same. Distance makes them look different. The same Distance makes them look different. The same

is true for stars. is true for stars. Two stars could be the same brightness but Two stars could be the same brightness but

their distance from us makes their brightness their distance from us makes their brightness different.different.

H-R DiagramH-R Diagram

1. The H-R Diagram shows us color, size, temperature, absolute magnitude and the life cycle of stars.

Hotter Cooler

Brighter

Dimmer

ConstellationsConstellations

1.1. A A constellationconstellation is a group of is a group of starsstars that appear to form patterns and that appear to form patterns and images in the sky.images in the sky.

2.2. The stars in a constellation are often The stars in a constellation are often vastly distant from each other, but vastly distant from each other, but they appear close to each other they appear close to each other from the perspective of Earth. from the perspective of Earth.

3.3. There are 88 constellations.There are 88 constellations.

CONSTELLATION ORION

Betelgeuse-

Red Star- Coolest

Rigel-

Blue Star-Hottest

ConstellationsConstellations

The 88 official constellations defined by The 88 official constellations defined by the IAU are mostly based upon those of the IAU are mostly based upon those of the ancient the ancient GreekGreek tradition, passed down tradition, passed down through the through the Middle AgesMiddle Ages, which includes , which includes the 'signs of the the 'signs of the zodiaczodiac,' twelve ,' twelve constellations through which the sun constellations through which the sun passes and which thus have had special passes and which thus have had special cultural significance. cultural significance.

The rest consist of constellations defined The rest consist of constellations defined in the in the early modern eraearly modern era by astronomers by astronomers who studied the who studied the southern hemispheresouthern hemisphere's 's skies, which were invisible to the Greeks.skies, which were invisible to the Greeks.

Zodiac Signs-What’s your Zodiac Signs-What’s your Sign?Sign?

LeoLeo, , VirgoVirgo, , LibraLibra, , ScorpiusScorpius, , SagittariusSagittarius, , CapricornusCapricornus, , AquariusAquarius, , PiscesPisces, , AriesAries, Taurus, Gemini, Cancer , Taurus, Gemini, Cancer

CapricornusCapricornusThe Sea GoatThe Sea Goat

This zodiacal constellation, like Pisces, depicts the This zodiacal constellation, like Pisces, depicts the result of the sudden appearance of the earthborn result of the sudden appearance of the earthborn giant Typhoeus. Bacchus was feasting on the banks giant Typhoeus. Bacchus was feasting on the banks of the Nile at the time, and jumped into the river. The of the Nile at the time, and jumped into the river. The part of him that was below water was transformed part of him that was below water was transformed into a fish, while his upper body became that of a into a fish, while his upper body became that of a goat. From this point of view, he saw that Typhoeus goat. From this point of view, he saw that Typhoeus was attempting to tear Jupiter into pieces; he blew a was attempting to tear Jupiter into pieces; he blew a shrill note on his pipes, and Typhoeus fled. Jupiter shrill note on his pipes, and Typhoeus fled. Jupiter then placed the new shape of Bacchus in the then placed the new shape of Bacchus in the heavens out of thanks for the rescue.heavens out of thanks for the rescue.

Capricornus has therefore from antiquity been Capricornus has therefore from antiquity been represented by a figure with the head and body of a represented by a figure with the head and body of a goat and the tail of a fish. It may be seen between goat and the tail of a fish. It may be seen between Aquarius and Sagittarius low on the southern horizon.Aquarius and Sagittarius low on the southern horizon.

AquariusAquariusThe Water CarrierThe Water Carrier

The water carrier represented by the The water carrier represented by the zodiacal constellation Aquarius is zodiacal constellation Aquarius is Ganymede, a beautiful Phrygian youth. Ganymede, a beautiful Phrygian youth. Ganymede was the son of Tros, king of Troy Ganymede was the son of Tros, king of Troy (according to Lucian, he was also son of (according to Lucian, he was also son of Dardanus). While tending his father's flocks Dardanus). While tending his father's flocks on Mount Ida, Ganymede was spotted by on Mount Ida, Ganymede was spotted by Jupiter. The king of gods became enamored Jupiter. The king of gods became enamored of the boy and flew down to the mountain in of the boy and flew down to the mountain in the form of a large bird, whisking Ganymede the form of a large bird, whisking Ganymede away to the heavens. Ever since, the boy away to the heavens. Ever since, the boy has served as cupbearer to the gods. Ovid has served as cupbearer to the gods. Ovid has Orpheus sing the tale: has Orpheus sing the tale:

"The king of the gods was once fired with love for "The king of the gods was once fired with love for Phrygian Ganymede, and when that happened Phrygian Ganymede, and when that happened Jupiter found another shape preferable to his own. Jupiter found another shape preferable to his own. Wishing to turn himself into a bird, he none the Wishing to turn himself into a bird, he none the less scorned to change into any save that which less scorned to change into any save that which can carry his thunderbolts. Then without delay, can carry his thunderbolts. Then without delay, beating the air on borrowed pinions, he snatched beating the air on borrowed pinions, he snatched away the shepherd of Ilium, who even now mixes away the shepherd of Ilium, who even now mixes the winecups, and supplies Jove with nectar, to the winecups, and supplies Jove with nectar, to the annoyance of Juno" (the annoyance of Juno" (MetamorphosesMetamorphoses X 154- X 154-160).Aquarius is a summer constellation in the 160).Aquarius is a summer constellation in the northern hemisphere, found near Pisces and northern hemisphere, found near Pisces and Cetus. It is especially notable as the radiant for Cetus. It is especially notable as the radiant for four meteor showers, the largest of which is the four meteor showers, the largest of which is the Delta Aquarid meteor shower in late July and Delta Aquarid meteor shower in late July and early August. early August.

Most Visible ConstellationsMost Visible Constellations Orion-The Great HunterOrion-The Great Hunter

Follow Orion’s Belt to Sirius, Follow Orion’s Belt to Sirius, the brightest star in the sky.the brightest star in the sky.

Ursa Major- The Big BearUrsa Major- The Big Bear

Ursa Major, the Greater Bear Ursa Major, the Greater Bear Zeus fell in love with Callisto, daughter of Lycaon (see under Lupus) and by her Zeus fell in love with Callisto, daughter of Lycaon (see under Lupus) and by her

had a son, Arcas. In order to spare Callisto from the wrath of Hera, Zeus changed had a son, Arcas. In order to spare Callisto from the wrath of Hera, Zeus changed her into a bear to hide her identityher into a bear to hide her identity

The Big Dipper

The Story of the Big BearThe Story of the Big Bear In ancient times, when the moonths In ancient times, when the moonths

were the annual calendar, people were the annual calendar, people studied astronomy to help them know studied astronomy to help them know when to plant and when to harvest. when to plant and when to harvest. They knew when the rivers were They knew when the rivers were likely to overflow...the Egyptians likely to overflow...the Egyptians noted that the cycles of the Dog Star, noted that the cycles of the Dog Star, Sirius, coincided with the rise and fall Sirius, coincided with the rise and fall of the Nile River. They could of the Nile River. They could accurately predict the Nile floods. accurately predict the Nile floods. Some of the Native American cultures Some of the Native American cultures noted that when the Big Dipper...they noted that when the Big Dipper...they could see Ursa Major, the Great could see Ursa Major, the Great Bear...dipped low in the western sky, Bear...dipped low in the western sky, the leaves of the trees would turn the leaves of the trees would turn red. Fall was here. red. Fall was here.

..

The story goes that three hunters were The story goes that three hunters were trailing the bear. The hunters were the three trailing the bear. The hunters were the three stars that we see as the handle of the Big stars that we see as the handle of the Big Dipper. One of the hunters had shot the bear Dipper. One of the hunters had shot the bear in the side, but the wound wasn't serious in the side, but the wound wasn't serious enough to stop the bear. The middle hunter enough to stop the bear. The middle hunter carried a pot on his shoulder to cook the bear carried a pot on his shoulder to cook the bear meat in, but the hunters never got close meat in, but the hunters never got close enough to kill the bear. He went crashing enough to kill the bear. He went crashing through the forests of the night, always through the forests of the night, always managing to keep the same distance ahead managing to keep the same distance ahead of the three hunters. At the end of summer, of the three hunters. At the end of summer, the bear and the hunters grew tired, and the bear and the hunters grew tired, and they dipped lower and lower toward the they dipped lower and lower toward the horizon. When the bear got very close to the horizon. When the bear got very close to the horizon, close enough for blood to drip from horizon, close enough for blood to drip from the wound in his side onto the trees, the the wound in his side onto the trees, the people noticed that the leaves turned red. It people noticed that the leaves turned red. It was time to harvest and finish preparation was time to harvest and finish preparation for winter.for winter.

The Big DipperThe Big Dipper The Big Dipper and Polaris play an The Big Dipper and Polaris play an

important part in the story of the important part in the story of the Underground Railroad which helped Underground Railroad which helped slaves escape their captivity in the slaves escape their captivity in the southern states of the United States southern states of the United States before the Civil War by fleeing north to before the Civil War by fleeing north to Canada. Canada.

The folk song "Follow the Drinking The folk song "Follow the Drinking Gourd" (another name for the Big Gourd" (another name for the Big Dipper) was a coded song that gave Dipper) was a coded song that gave directions on the escape route from directions on the escape route from Alabama and Mississippi. While Alabama and Mississippi. While traveling on their long escape journey, traveling on their long escape journey, they could always tell which way was they could always tell which way was north by the location of Polaris which north by the location of Polaris which they could find by the pointer stars.they could find by the pointer stars.

Ursa Minor-The Little BearUrsa Minor-The Little Bear

Ursa Minor, the Lesser Bear Ursa Minor, the Lesser Bear Hera, discovering the tryst Zeus had had with Callisto (see Ursa Major), convinced Arcas to Hera, discovering the tryst Zeus had had with Callisto (see Ursa Major), convinced Arcas to

hunt after his mother, who had been changed into a bear by Zeus. To protect Callisto, Zeus hunt after his mother, who had been changed into a bear by Zeus. To protect Callisto, Zeus changed Arcas into a bear and carried them both by their tails to the heavens, where they changed Arcas into a bear and carried them both by their tails to the heavens, where they became constellations. Annoyed at this honor, Hera convinced Poseidon not to allow the became constellations. Annoyed at this honor, Hera convinced Poseidon not to allow the bears to bathe in the sea. For this reason, Ursa Major and Ursa Minor never sink below the bears to bathe in the sea. For this reason, Ursa Major and Ursa Minor never sink below the horizon. horizon.

Vela, the Sails Vela, the Sails

Create a constellation based Create a constellation based on the letters in your nameon the letters in your name

Complete grid using the letters of your name.Complete grid using the letters of your name. Transfer points to second grid. Transfer points to second grid. Create a shape with the letters and create a story Create a shape with the letters and create a story

that explains why your constellation is in the sky. that explains why your constellation is in the sky. Name your constellation after yourself or after the Name your constellation after yourself or after the shape. shape.

Cut out your constellation and glue to Cut out your constellation and glue to construction paper. construction paper.

Write your story and the paper provided and glue Write your story and the paper provided and glue to bottom of paper.to bottom of paper.

Due Friday, 2/6/09Due Friday, 2/6/09

Life Cycle of our SunLife Cycle of our Sun

1.1. Stellar NebulaStellar Nebula

2.2. ProtostarProtostar

3.3. Main SequenceMain Sequence

4.4. Red GiantRed Giant

5.5. Planetary NebulaPlanetary Nebula

6.6. White DwarfWhite Dwarf

7.7. Black DwarfBlack Dwarf

Life Cycle of a Massive Life Cycle of a Massive StarStar

1.1. Stellar NebulaStellar Nebula

2.2. ProtostarProtostar

3.3. Blue GiantBlue Giant

4.4. Red SupergiantRed Supergiant

5.5. SupernovaSupernova

6.6. Neutron Star Neutron Star

(Pulsar)(Pulsar)

OROR

77. Black Hole. Black Hole

Life Cycle of A StarLife Cycle of A Star1. Stars begin their lives as clouds of dust 1. Stars begin their lives as clouds of dust

and gas called a stellar nebula.and gas called a stellar nebula.

A ProtostarA ProtostarThe gravity of a passing star or the shock wave The gravity of a passing star or the shock wave

from a nearby supernova may cause the nebula from a nearby supernova may cause the nebula to contract.to contract.

1. Matter in the gas cloud will begin to come 1. Matter in the gas cloud will begin to come together into a dense region called a protostar. together into a dense region called a protostar.

2. As the2. As the protostar continues to condense, it heats protostar continues to condense, it heats up. up.

3. Eventually, it reaches a critical mass and3. Eventually, it reaches a critical mass and nuclear fusion begins. nuclear fusion begins.

4. This begins the main sequence phase of the 4. This begins the main sequence phase of the star. Our Sun is a main sequence star. star. Our Sun is a main sequence star.

PROTOSTAR

Main Sequence StarsMain Sequence Stars

1. The life span of a star depends on 1. The life span of a star depends on its size.its size.

2. Very massive stars will become blue 2. Very massive stars will become blue giants during their main sequence. giants during their main sequence.

Their main sequence may last only a Their main sequence may last only a few hundred thousand years. few hundred thousand years.

3. Smaller stars, like the Sun, will burn 3. Smaller stars, like the Sun, will burn for several billion years during their for several billion years during their main sequence stage.main sequence stage.

4. Our Sun is in its main sequence. 4. Our Sun is in its main sequence.

Average sized star like our Sun during main sequence.

Massive star larger than our Sun during main sequence

The main sequence is the longest part of a star’s life

Red Giant and Red Supergiant Red Giant and Red Supergiant

1. Eventually,1. Eventually, the star's fuel will begin the star's fuel will begin to run out.to run out.

2. Our Sun will expand into what is 2. Our Sun will expand into what is known as a red giant.known as a red giant.

3. Massive stars will become red 3. Massive stars will become red supergiants. supergiants.

4. This phase will last until the star 4. This phase will last until the star exhausts its remaining fuel. exhausts its remaining fuel.

5. At this point, the star will collapse. 5. At this point, the star will collapse.

Our SunOur Sun

1. Most average stars will blow 1. Most average stars will blow away their outer atmospheres to away their outer atmospheres to form a planetary nebula. form a planetary nebula.

2. Their cores will remain behind 2. Their cores will remain behind and burn as a white dwarf until and burn as a white dwarf until they cool down.they cool down.

3. What will be left is a dark ball of 3. What will be left is a dark ball of matter known as a black dwarf. matter known as a black dwarf.

Planetary Nebula

White Dwarf

Massive StarsMassive Stars

1. If the star is massive enough, the collapse 1. If the star is massive enough, the collapse will trigger a violent explosion known as a will trigger a violent explosion known as a supernova. supernova.

2. If the remaining mass of the star is about 2. If the remaining mass of the star is about 1.4 times that of our Sun, it will collapse 1.4 times that of our Sun, it will collapse further to become a neutron star.further to become a neutron star.

3. If the remaining mass of the star is more 3. If the remaining mass of the star is more than about three times that of the Sun, it than about three times that of the Sun, it will collapse and what is left behind is an will collapse and what is left behind is an intense region of gravity called a black intense region of gravity called a black hole. hole.

Massive Stars (Larger than Massive Stars (Larger than our Sun)our Sun)

Become Red Supergiants.

Red Supergiant becomes Red Supergiant becomes Supernova in a giant Supernova in a giant

explosion,explosion,

OR OR It becomes a Black It becomes a Black HoleHole

This is an illustration, not an actual black hole!!

Supernova Becomes a Supernova Becomes a Neutron StarNeutron Star

Life Cycle of our SunLife Cycle of our Sun

1.1. Stellar NebulaStellar Nebula

2.2. ProtostarProtostar

3.3. Main SequenceMain Sequence

4.4. Red GiantRed Giant

5.5. Planetary NebulaPlanetary Nebula

6.6. White DwarfWhite Dwarf

7.7. Black DwarfBlack Dwarf

Life Cycle of a Massive Life Cycle of a Massive StarStar

1.1. Stellar NebulaStellar Nebula

2.2. ProtostarProtostar

3.3. Blue GiantBlue Giant

4.4. Red SupergiantRed Supergiant

5.5. SupernovaSupernova

6.6. Neutron Star Neutron Star

(Pulsar)(Pulsar)

OROR

77. Black Hole. Black Hole

Interactive Website

• http://aspire.cosmic-ray.org/labs/star_life/starlife_main.html