Transcript ISM presentation slides

Chapter 11: The Interstellar Medium
Region in the
Constellation Orion
named the Orion Nebula
which is the closest star
formation region to us.
Jets and disks appear to
be part of the star birth
process
Chapter 11: The Interstellar Medium
The interstellar medium is the region
between the stars. It is composed of
gas and dust that ultimately are the
raw materials from which stars and
planetary systems are made.
This wide angle photograph of our
milky way galaxy shows dark dust
lanes cutting through the plane of our
galaxy.
Chapter 11: The Interstellar Medium
Astronomers can determine
what the interstellar material
is made of, its temperature,
and velocity by observing the
absorption lines produce
when starlight passes through
the clouds of material.
Blue light is also scattered
more easily than red so the
red light makes it through
better, thus objects appear
reddened.
Chapter 11: The Interstellar Medium
The clouds and dust of the interstellar medium tend to be cold
and thin by our standards. Average temperature is 100 K with
an average density of one atom per cm3.
On average there is one dust particle for every trillion atoms.
Chapter 11: The Interstellar Medium
Emission Nebula
Chapter 11: The Interstellar Medium
Dark Nebula
Chapter 11: The Interstellar Medium
21 centimeter radiation is produced
when the spins of the electron and
proton flip in a Hydrogen atom.
Radio astronomers can thus map out
the distribution of Hydrogen
throughout the galaxy
Chapter 11: The Interstellar Medium
Star formation take about 10
million years
Chapter 11: The Interstellar Medium
The emission part of the star
formation region is only a small part
of the giant cloud.
Chapter 11: The Interstellar Medium
The Orion Nebula
Chapter 11: The Interstellar Medium
More Orion
Individual stars forming in density fingers
Chapter 11: The Interstellar Medium