General Astronomy Quiz 11 Flashcards

1
Q

When does an object appear bright to us?

A

When it is close to us or inherently bright

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1
Q

What is magnitude used to measure?

A

Brightness

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2
Q

What does a smaller magnitude mean?

A

Smaller magnitude=brighter star

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3
Q

What is apparent brightness?

A

It is measured by a rate of photons collected by a telescope

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4
Q

What is absolute brightness?

A

The true brightness of an object, or a star’s luminosity

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5
Q

How is luminosity found?

A

By multiplying the power produced per area by the surface area of the star

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6
Q

Who observed the Sun’s absorption lines?

A

Joseph Fraunhofer

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7
Q

Who discovered dark lines in the spectra of other stars?

A

Sir William and Lady Margaret Huggins

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8
Q

Who analyzed the amount of stellar spectra data to catalog star types?

A

The Harvard Computers

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9
Q

What did Williamina Fleming do?

A

She grouped stars into different alphabetical categories based on their hydrogen absorption lines

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10
Q

What did Annie Jump Cannon do?

A

She revised the system by including info about peak wavelength and sorting categories by temp

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11
Q

Which stars are the most massive, largest, bluest, and hottest?

A

O stars

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12
Q

Which stars has the least mass, smallest, reddest and coldest?

A

M stars

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13
Q

What are brown dwarfs?

A

Too small to be a star, but too big to be a planet (types of L, T, Y)

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14
Q

What do brown dwarfs have?

A

Deuterium fusion
-About as large as Jupiter
-13-80 times the mass

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15
Q

What is the Doppler Effect?

A

The shift in the frequency and wavelength of a wave due to relative motion

16
Q

If a star is close enough, we can track its ____

A

Proper motion

17
Q

What will proper motion change?

A

All of our constellations

18
Q

What does the width of lines tell us about?

A

A star’s rotation

19
Q

What do the rotations mean?

A

The thin line gets smeared because of the portion being redshifted and blueshifted

20
Q

What is solar neighborhood?

A

When the volume of space that is going to be used is determine

21
Q

Which stars are the most common?

22
Q

Can we measure a single star’s mass by the light we receive from it?

23
Q

What happens if we have two or more stars in orbit around each other?

A

We can study their motion

24
What do binary stars orbit?
Around a center of mass point
25
How do astronomers study binary stars?
1. Visual Binary 2. Spectroscopic Binary 3. Eclipsing Binary
26
What is visual binary?
● Far enough apart to be resolved as separate points ● Orbiting in the plane of the sky
27
What is spectroscopic binary?
The spectrum of the star is used and the Doppler shift is measured as the stars move
28
What is eclipsing binary?
The tracking of brightness and making a light curve that is studied, if the system is perfectly aligned
29
What is mass luminosity?
When the luminosity can tell us mass
30
How can you calculate the radius of stars?
By calculating the luminosity and measuring the temperature
31
What is the Hertzsprung-Russell Diagram?
It can plot related qualities and is one of the most important plots in astronomy
32
Where can we find the largest and smallest stars?
-L (red giants): Upper Right of HR -S (white dwarfs): Lower Left of HR
33
What is used to determine distance?
Triangulation
34
What is stellar parallax?
The measurement of apparent shifts of a star's position against background stars