 Milky Way Galaxy Cierra Yoshikawa Tomohiro Hoshino

What is the Milky Way Galaxy?  Spiral galaxy  Containing 400 billion stars including our solar system  Plus gas and dust  x750 solar mass

What is the Milky Way Galaxy?  light year in diameter  Formed by the collapse of a large region of gas and dust  Part of group of galaxies called the Local Group  Group of 30 galaxies that are about 5 million light years across

Other Info

Milky Way Arms  Perseus Arm  Saittarius Arm  Cygnu Arm  Orion Arm (our solar system)  Norma Arm  Sctum-Crux Arm

3 General Components  The halo  Nuclear bulge  The disk

The Halo  Consists of the oldest stars and dark matter, absence of gas or dust  146 Globular Clusters  Spherical shape  Believed to be formed billion yrs ago  Produces hot gas called gamma-ray halo

The Disk  Contains the sun and other intermediate- to young stars (million –ten billion years old), gas and dust  Approximately 300pc (1,000 light years) thick and 30kpc (100,000 light years) in diameter

The Disk Cont.  Sun sits about 2/3 of the way from the center to the edge of the disk.  Sun revolves around the center every 250 years

Nuclear Bulge  The center of the Galaxy  Dimension 1kpc by 6kpc  Shaped like a football  Crowded with stars which are 10 billions years old or older (population II)

Nuclear Bulge Cont.  The most brightest region is called Sgr A  ~ 2 x 10 6 M of Sun within 1 pc  Stars are only 1000 AU apart  A collision every 10 6 years

Types of Stars  Population I:  Younger, metal-rich stars  Found in disk  Population II:  Older, metal- poor stars  Found in halo

View from Earth  Can only be seen on a clear night  Looks like a band of stars splashed on the sky  Can’t see spiral structure from Earth, images of structure created from computer modeling based on information from stars as they orbit the galaxy  Most of it in invisible from Earth due to being in the disk  5,000-8,000 stars visible from Earth

View from Earth

Works Cited  “Our Solar System in the Milky Way Galaxy.” N.p. N.d. Web. 16 April  “Our own Galaxy-The Milky Way.” Cambridge Cosmology: Galaxies, N.d. Web. 16 April  “The Milky Way Galaxy.” N.p. 25 Aug Web. 16 April  “The Milky Way Galaxy.” University of California, San Diego Center for Astrophysics & Space Sciences, N.d. Web. 16 April