Neutron star more like neutrON the grind (tehe)

1.      How does mass affect the curvature of spacetime?

Mass distorts the “fabric” of spacetime, causing gravity and where gravity is stronger time will be slower.

How do black holes affect the curvature of spacetime?

Black holes cause a tear in spacetime because the mass is becoming so small and dense.

  Gravitational Lensing – recognize this in pictures and be able to explain what is happening.

Light takes the fastest path through space which happens to be curved due to planets causing distortions in spacetime.

1.      What does gravitational time dilation entail?

As gravity increases time will slow down.

  Gravitational Waves – what are they and how are they created?

They are ripples in spacetime that travel at the speed of light, they occur when there is changes in massive objects

What is nuclear fusion?

Nuclear fusion is the process where two hydrogen molecules are slammed together to create helium

How is fusion different from fission?

In nuclear fusion atoms combine to form heavier nucleus’s but in nuclear fission larger atoms split apart to create energy.

How is the temperature in the sun’s core regulated?

As temperature of the sun’s core increases the the core expands to help regulate temperature, and if the core temperature decreases the core would contract to help regulate the cores temperature.

What is the spectral order type from hottest (biggest) to coolest (smallest)?

O B A F G K M

2.      Relative sizes of different types of stars: Main sequence stars, giants, supergiants, white dwarfs, and neutron stars

Supergiants- Humongous (high mass stars turn into these before dying)

Giants- Pretty big (low mass stars turn into these before dying)

Main Sequence Stars- Medium Sized (our sun)

White dwarfs- Pretty small about the size of the earth (core’s of low mass stars)

Neutron stars- Really small and dense about the size of Atlanta, cores of stars that were big enough to become black holes, but did not.

What are stars doing on the main sequence?

Low-mass stars are Fusing Hydrogen (H) to Helium (He) through the proton-proton chain. High mass stars are also fusing hydrogen to helium through the CNO Cycle, and then heavier elements until their core heats up and they turn into supergiant.

How could we get variable stars?

A star that is pulsating because it cannot achieve a gravitational equilibrium with gravity and pressure always in competition with eachother.

Open clusters vs. Globular Stars

Open clusters are younger (main sequence) globular clusters are older (white dwarfs and supergiants)

1.      What do stars form out of?

Molecular Clouds

Do stars tend to form in groups, or as single stars?

They tend to form in groups because the molecular clouds have a lot of mass.

What are the four general stages of star birth/formation?

• 1st stage- Molecular cloud uniform density just existing in space

• 2nd stage- Incoming shockwave creates gravitational instabilities, creating little pockets of density, the surrounding gas in the little pockets collapses down

• 3rd stage- Material is spiraling down into the condensed region where the star is working on forming. (just before protostar stage) 

• 4th stage- Protostar is formed with the accretion disk around it. Bipolar jets of material coming out of it.

1.      What are brown dwarfs? How are they different from regular stars?

If a protostar does not have enough mass to become a star it will turn into a brown dwarf

1.      What are the most common stellar mass? Low, intermediate, or high?

Low mass

How does mass affect the rate of fusion in the core of a star?

The higher the mass the higher the rate of fusion the core of a star will have.

What are the general stages of a low mass star’s life?

Main sequence-red giant-helium flash-planetary nebular-white dwarf

What are the general stages of a high mass star’s life?

Main sequence-supergiant-supernova-neutron star or black hole

What does a high mass star create after it dies?

A neutron star or a black hole

What does a low mass star create after it dies?

White dwarf

Which stars fuse elements heavier than He

High mass stars.

How does mass affect lifetime?

The higher the mass the shorter the lifetime because it will fuse elements faster.

Why does mass matter for close binary star systems?

It is the main way to determine the distance of stars.

What is mass exchange/transfer?

When a star in a close binary system starts to swell in size at the end of its main-sequence stage, it can start to transfer mass to its companion, which can change the life of both of the stars.

What is a white dwarf? Why doesn’t it just collapse in on itself?

A white dwarf is the left over core of a low mass star, it does not collapse in on itself because of electron degeneracy pressure in which the electrons are packed so tightly together that they have nowhere to go.

How can white dwarfs in close binary systems experience/create

The white dwarf will acquire hydrogen from its companion through an accretion disk where the matter is swirling around the white dwarf's surface. As the hydrogen builds on the surface it can ignite nuclear fusion and produce a nova, and cause the merger of the two white dwarfs, and possibility cause the white dwarf to approach its limit and explode into a white dwarf supernova.

What is a neutron star? Why doesn’t it just collapse in on itself?

A neutron star is the left over cores of high mass stars after a supernova they are extremely dense and neutron degeneracy pressure prevents the crush of gravity.

What are pulsars? How are they different from neutron stars and white dwarfs?

Neutron star that has a really strong magnetic field that causes beams of light (radiation) to come out of the poles of that start, when the beams are offset (45 degrees) from the axis around it is rotating. 

What can neutron stars in close binary systems experience/create?

They can accrete hydrogen materials from their companions, forming accretion disks. The hot gas emits strongly in x-rays so we see the systems as x-ray binaries. In some of the systems, the helium fusion ignites sporadically on the neutron star’s surface, resulting in x-ray bursts.

What is a black hole?

A black hole is formed when a high mass star has enough gravity to do so in a black hole gravity crushes matter, and nothing can escape from a black hole.

1.      What happens when black holes merge? What happens when neutron stars merge?

Neutron stars merge as a result of the emission of their gravitational waves. When they merge the energy released is bigger than that of a massive star supernova resulting in the production of rare elements (that are rich in neutrons). Most of the star will remain gravitationally bound to the system but parts of it are ejected into interstellar space.

Black holes also merge due to their strong projection of gravitational waves, when they merge they form an even bigger black hole.

What can create a gamma-ray burst?

Gamma-ray bursts are caused from unusually powerful supernova explosions that can create black holes, or the mergers of neutron stars in close binary systems.