According to Pg 15 of the ESRT, Which star color indicates the

hottest star surface temperature?

(1) blue (3) yellow

(2) white (4) red

Twinkle Twinkle Little (1 x 1029) Stars

We are on the Earth (4.6 x 109 years old)

Earth circles sun in Solar System (heliocentric)

Solar system is in Milky Way Galaxy (≈ 13.2 x 109 years old)

Milky Way Galaxy is in the Universe ( 13.7 x 109 years old)

Dub set is here!

Starlight informs us about a stars: age,

composition, distance, velocity & more.

The universe is big and it is expanding!

Let’s study stars and their light…

Dust--in a nebula--is pulled together by gravity.

When the mass and heat reach a critical point, Hydrogen fusion begins .

The star is “born” and begins to emit light (radiation).

http://video.pbs.org/video/2226474716/

Which process produces the energy that allows the stars of the

universe to radiate visible light?

(1) convection

(2) Insolation

(3) nuclear fusion

(4) radioactive decay

Stars live in a “tug-of-war” between fusion energy pushing out and gravity pulling in.

When the hydrogen fuel runs out, whathappens next depends on the star’s original

mass.

Our sun is a small star. What happens when it runs out of hydrogen fuel to fuse?

Which star has about the same temperature as the sun, but is about 5000 times brighter (more luminous)?

What is the temperature of a “main sequence” star with a luminosity of

about 50?

Luminosity Charts help to

describe this Stellar Evolution.