Reminders

Due by the end of the day:– Analysis of 10 datasets– Questions from Section 2 of Searching for and

Analyzing Pulsars

Tonight: I will (along with Mrs. Hedrick) be grading your responses for Section 1 questions.

Bellwork

Degenerate Matter and PressureA review from yesterday

Why do you think degenerate gas behaves more like a sold than the gas you are familiar with here on Earth?• Discuss your predictions with your group

Q: Why do degenerate gases resist compression?

A:

Q: Describe how the source of pressure in normal matter and degenerate matter differ.A: Normal Matter Degenerate matter

Electromagnetic Repulsion from atoms (in the case of you and me and planet Earth)OrThermal and radiative pressure from thermonuclear fusion (in the case of stars)

Degeneracy Pressure Electron degeneracy pressure (in the case of a white dwarf star)Neutron degeneracy pressure (in the case of a neutron star)

Both examples depend on the temperature of the atoms/particles in the system

The pressure depends only on the degenerate electrons – if heat is added the electron pressure does not increase.

Follows Ideal Gas law

DOES NOTFollow Ideal Gas law

Q: What happens to the volume of a white dwarf or neutron star when mass is added onto its surface? How is this different from normal matter?A: Volume when mass is added

Normal Matter Increases

Degenerate Matter Decreases

Q: What is the name of the mass limit for white dwarf stars? It is the boundary between what two evolutionary endpoints?A: Chandrasekhar Limit ~ 1.44

Size Comparison

• What is the mass limit for neutron stars? What is the name and value for this limit?

A: The Tolman-Oppenheimer-Volkoff Limit ~ 3

Do the pulsar masses fit the

predicted models developed by

Chandrasekhar and the TOV

group?

Size comparison

The Interiors of Neutron Stars

An article review

Whale of a Burst

Artists conception of Magnetar Gamma Ray Burst (SGR 1806-20)

Artists conception of Star Quake

SWIFT Spike in gamma photons

You can get this on a T-shirt

Neutron Star Crust is Stronger than Steel

Gianormous flare caused by Star Quakes!

Solid Crust – Fluid Interior

Possibly small mountains on the surface – really

small!

Journey to the Center of a Neutron StarWatch an animation of a glitch pulse here: http://www.nasa.gov/mpg/108574main_neutron_%20star_animation.mpg

Chemistry of a neutron star modeled for first time

Gamma and X-ray emission during zombie-ismhttp://www.nasa.gov/centers/goddard/mpeg/97911main_Puff.0539.mpeg

Exploded Star Reveals Strange New MatterCas A Supernova Remnant: http://www.youtube.com/watch?v=mJaFHq3OaMg

Cas A is a young pulsar. It has slowed down tremendously over the last 10 years ~ 4%.

This is believed to be due to the rapid cooling of the inside.

Forming superfluid and super conductors (Resistance free material – this allows electrons to flow freely)

Superfluid's on Earth: (small clip)http://www.youtube.com/watch?v=2Z6UJbwxBZISuperfluid’s on Earth (long clip)http://www.youtube.com/watch?v=bmvlIdNXxjM

Now, let’s put all the information about the interior of a neutron star together and create a 2-

D or 3-D model representing what we have learned.

• Groups of 2 or 3• You can create a 2-D model using markers• Or a 3-D model using play doughEither way you must have a way to label and describe each layer