General Astronomy Quiz 11 Flashcards
When does an object appear bright to us?
When it is close to us or inherently bright
What is magnitude used to measure?
Brightness
What does a smaller magnitude mean?
Smaller magnitude=brighter star
What is apparent brightness?
It is measured by a rate of photons collected by a telescope
What is absolute brightness?
The true brightness of an object, or a star’s luminosity
How is luminosity found?
By multiplying the power produced per area by the surface area of the star
Who observed the Sun’s absorption lines?
Joseph Fraunhofer
Who discovered dark lines in the spectra of other stars?
Sir William and Lady Margaret Huggins
Who analyzed the amount of stellar spectra data to catalog star types?
The Harvard Computers
What did Williamina Fleming do?
She grouped stars into different alphabetical categories based on their hydrogen absorption lines
What did Annie Jump Cannon do?
She revised the system by including info about peak wavelength and sorting categories by temp
Which stars are the most massive, largest, bluest, and hottest?
O stars
Which stars has the least mass, smallest, reddest and coldest?
M stars
What are brown dwarfs?
Too small to be a star, but too big to be a planet (types of L, T, Y)
What do brown dwarfs have?
Deuterium fusion
-About as large as Jupiter
-13-80 times the mass
What is the Doppler Effect?
The shift in the frequency and wavelength of a wave due to relative motion
If a star is close enough, we can track its ____
Proper motion
What will proper motion change?
All of our constellations
What does the width of lines tell us about?
A star’s rotation
What do the rotations mean?
The thin line gets smeared because of the portion being redshifted and blueshifted
What is solar neighborhood?
When the volume of space that is going to be used is determine
Which stars are the most common?
M stars
Can we measure a single star’s mass by the light we receive from it?
No
What happens if we have two or more stars in orbit around each other?
We can study their motion
What do binary stars orbit?
Around a center of mass point
How do astronomers study binary stars?
- Visual Binary
- Spectroscopic Binary
- Eclipsing Binary
What is visual binary?
● Far enough apart to be resolved
as separate points
● Orbiting in the plane of the sky
What is spectroscopic binary?
The spectrum of the star is used and the Doppler shift is measured as the stars move
What is eclipsing binary?
The tracking of brightness and making a light curve that is studied, if the system is perfectly aligned
What is mass luminosity?
When the luminosity can tell us mass
How can you calculate the radius of stars?
By calculating the luminosity and measuring the temperature
What is the Hertzsprung-Russell Diagram?
It can plot related qualities and is one of the most important plots in astronomy
Where can we find the largest and smallest stars?
-L (red giants): Upper Right of HR
-S (white dwarfs): Lower Left of HR
What is used to determine distance?
Triangulation
What is stellar parallax?
The measurement of apparent shifts of a star’s position against background stars
