Where are Stars Formed?

• Stars are born within clouds of gas and dust scattered throughout the galaxies

• These clouds of gas and dust are called “nebula”

• An average star takes about 50 million years to go from the start of the nebula to becoming an active star

Nebulas: Example

Orion Nebula

• Most Famous of all nebulas

• 1500 light-years away• Several stars are

forming inside this nebula

Butterfly Nebula

• FFou • Found in the constellation Scorpio

• 3800 light-years away

Cat’s Eye Nebula3300 light years away from Earth

First discovered by William HerschelIn 1786

Found in constellation “Draco the Dragon”

Hourglass

NebulaLocated in the constellation “Musca” the fly.

Located in the Southern Hemisphere sky

8000 light-years from Earth

ProtostarGravity causes the gases of the cloud to collapse toward the center

As the gases in the center become more dense and hot, a protostar forms

ProtostarAs the core of the protostar gets bigger, the pressure and heat gets greater.

When the temperature reaches 15 million ºC, nuclear fusion begins and active star forms

Two Astronomers working alone came up with the same major discovery in 1911

Ejnar Hertzprung- Working in HollandHenry Rollins Russell- working in Princeton, New Jersey

H-R Diagram

Betelgeuse: An Example of a Red Supergiant Star

• Name: Betelguese• Translation: Arabic for

“armpit of the great one”

• Distance 642 light years• Surface Temperature:

3500 K• Will become a

supernova

Where is Betelgeuse?

• Found in the constellation Orion, “The Great Hunter”

How Big Is Betelgeuse?

Supernovas: The Explosion of a Massive Star

Blue SupernovaRelease of the outer layers of the sun

Leaves behind either:

neutron star black hole

Neutron StarVery dense- one teaspoon full would weigh a billion pounds on Earth

Very small (20 Km)

Often releases bursts of energy (called pulsars)

BlackholeProduced by the collapse of the largest, hottest stars.

Gravity is so strong that light can’t escape.