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Details

Ole Miss Astr 104 Prof Summers Test 2
Combination of questions from in class exam and make up exam
46
Astronomy
Undergraduate 1
12/08/2009

Additional Astronomy Flashcards

 


 

Cards

Term
Name 4 Stars
Definition

Polaris

Sirius

The Sun

Bettleguese

Term
What is the speed of light in kilometers per second?
Definition

Light travels at 

300,000 km/s

Term
If we lived on Mars rather than the earth, would the shift in star positions due to parallax be larger, smaller, or the same?
Definition
Larger
Term
What did Galileo measure using sunspots in the 1660's?
Definition
Solar rotation rate
Term

Which one solar mass star is the largest?

Red giant, white dwarf or the sun

Definition
Red giants
Term
What does hydrogen become in the core of the sun that releases energy today?
Definition

Hydrogen becomes 

Helium

in the sun to release energy

Term
Is it thought that virtually all 10 solar mass stars will become supernova?
Definition

Yes

Virtually all 10 solar mass stars will become supernova

Term
Which stars have hotter surfaces, red or blue?
Definition

Blue 

stars have hotter surfaces

Term
True or False: All main sequence stars convert hydrogen to helium in their cores
Definition
True
Term
True or False: Star clusters with lots of bright blue stars are young
Definition
True
Term
Which is brighter, a 2nd magnitude star of a 6th magnitude star?
Definition

The 2nd magnitude star

 

The lower the magnitude number the brighter the star. A -2 magnitude is brighter than a 1, etc.

Term
Why doesn't gravity cause a main sequence star to collapse?
Definition

Hot gas pressure

stops gravity from collapsing a main sequence star

Term
How many years until the Sun become a Red Giant?
Definition

The Sun will become a Red Giant in

5 Billion Years

Term
What is the core of an isolated 10 solar mass start made of just before it supernovas?
Definition

The core of a 10 solar mass star is made of

Iron

just before it supernovas

Term
What is the source of energy in an early pre-main sequence star?
Definition

Gravitational contraction

is the source of energy in an early pre-main sequence star

Term
What is the Chandasekhar limit for the stability of white dwarf stars equal to in solar masses?
Definition

1.4 solar masses

is the Chandasekhar limit for the stability of white dwarf stars

Term
Why are sunspots cooler than the rest of the surface of the Sun?
Definition
Magnetism slows convection
Term
What is the dominant energy source for the sun today?
Definition

Hydrogen fusion into helium

is the dominant energy source for the Sun today

Term
From what part of the Sun do solar neutrinos observed on earth originate?
Definition

Solar neutrinos observed on earth originate in sun's

Core

Term

Which of the following is on the Main Sequence of the Hertzsprung-Russell (HR) diagram?

 

White dwarfs, the sun or red giants?

Definition

The Sun

is on the main sequence

Term
Through what angle can a nearby star appear to move in 6 months due to parallax?
Definition

A nearby star can appear to move

one second of arc

in a 6 month period

Term
What diagram might you look at to find the age of a star cluster?
Definition

Luminosity-Temperature diagram

can tell you the age of a star cluster

Term
Which sub-atomic particle can pass most quickly from the core to the surface of the sun?
Definition

Neutrinos

pass most quickly 

Term
Do nearby or distant stars appear to move more due to parallax?
Definition

Nearby stars

appear to move more due to parallax

Term
What causes mass transfer in a binary star system?
Definition

Tides

cause mass transfer in a binary star system

Term
If 1000 grams of hydrogen atoms are converted into helium atoms in the core of the Sun, what will be the mass of the helium atoms?
Definition
993 grams
Term

Which of these one solar mass stars would have the lowest luminosity?

 

Main sequence, red giant, or white dwarf?

Definition
White dwarf would have the lowest luminosity of those three
Term
Why doesn't a White Dwarf star collapse?
Definition

Degenerate electron gas

prevents a white dwarf star from collapsing

Term
How long can a one solar mass star like the sun live on the main sequence?
Definition

A one solar mass star like the sun can live

10 billion years

on the main sequence

Term
What can helium become in the core of a Red Giant that releases energy?
Definition

Helium becomes

Carbon

in the core of a red giant releasing energy

Term
If the distance to a star were to triple, how much dimmer would it appear?
Definition

*The brightness of a star decreases as the square of distance*

 

3^2= 9

9x dimmer

 

Term
A binary star system is found with a semi-major axis of 20 AU and a period of 50 years. How many solar masses are in the system?
Definition

*Binary star system mass= orbital size cubed divided by the period squared*

 

3 Solar Masses 

Term
What important quantity can be calculated from the luminosity (absolute magnitude) of a star and its apparent magnitude?
Definition

Distance 

can be calculated from the luminosity of a star and its apparent magnitude

Term
If the surface temperature of a star were to double, what would happen to the energy output? Diameter is fixed.
Definition
Energy output would go up 16x
Term
Which sub-atomic particle can pass through the earth?
Definition

Neutrinos

can pass through the earth

Term
What is plotted on the Hertzsprung-Russell Diagram of Stars?
Definition

Temperature vs. Luminosity

is plotted on the HR Diagram

Term
During what phase does a star spend most of its time?
Definition

A star spends most of its time on

the Main Sequence

Term
Can a shock wave trigger star formation?
Definition
Yes, a shock wave can trigger star formation
Term
Can an isolated one solar mass star like our sun become a supernova?
Definition
No, an isolated one SM star like the sun cannot become a supernova
Term
What must be added to a white dwarf to make it become a supernova?
Definition

Mass

must be added to a white dwarf to make it become a supernova

Term
What would happen to the radius of a half solar mass black hole if it ate the Sun?
Definition

If a half solar mass black hole ate a 1 solar mass star, its radius would

increase 3x

Term
At some point in time what will our Sun eventually become?
Definition
A white dwarf
Term
In X-Ray light, which is brighter, Sirius A or Sirius B?
Definition

Sirius B

is brighter in X-Ray light

Term
Can the emission of gravity waves by two neutron stars in orbit around each other cause the orbital period to change?
Definition

Yes

The emission of gravity waves by two neutron stars in orbit around each other can cause the orbital period to change

Term
Is it possible to see inside a black hole from the outside?
Definition

No

it is impossible to see the inside of a black hole from outside it

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