Midterm 2

Question 1

Doppler Effect

Answer 1

• motion induced change in the observed frequency
• towards, blue, shorter wavelength higher frequency
• away from, red, longer wavelength, lower frequency

Question 2

Telescope

Answer 2

• light bucket capture as many photons as possible. light bucket
• modern are large and reflectors
• bigger more radiation collection
• magnify and resolve

Question 3

Refraction

Answer 3

• bending of a light beam, glass lens
• hard to make large, hard to support
• chromatic aberration
• lens’ absorb

Question 4

Resolving Power

Answer 4

• ability of a device to form distinct separate images

- large telescopes higher angular resolution

Question 5

Atmospheric Blurring

Answer 5

• atmospheric turbulence. twinkling
• seeing: even in transparent atmosphere, it can distort images. diffraction limits
• high altitude

Question 6

Radio Telescopes

Answer 6

• extremely large
• faint signals
• large wavelength

Question 7

Adaptive Optics

Answer 7

-change the shape of the telescopes to correct for atmospheric blurring

Question 8

Solar Structure

Answer 8

• core. nuclear fusion, highest temp most dense
• radiation zone.
• convection zone
• photo-sphere: energy escapes, what we see
• chromo-sphere: cool lower atmosphere
• transition zone: rapid temperature increase
• corona: hot, low density upper atmosphere
• solar wind is the material that escapes in to the atmosphere

Question 9

Fusion

Answer 9

-combines light nuclei making heavier ones thereby releasing energy in the form of gamma rays
E= mc^2

Question 10

Proton Proton Chain

Answer 10

• Need 10^7 temperature
• electromagnetic repulsion otherwise
• proton and proton make deuterium and positron and neutrino
• proton proton proton proton in to Helium 4 gamma rays and 2 neutrinos

Question 11

Larger Mass

Answer 11

-use more energy and live shorter

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Question 12

Star Radius Hierarchy

Answer 12

Super Giant -100-1000 1A 1B
Giant- 10-100 Bright II, III, Sub IV
Brown/Red Dwarf- Jupiter V	
White Dwarf- Earth V
Neuron- 20km V
Pulsar- 20km V 
Black Holes- 10 km
MOST ARE 0.01-100 RADIUS OF SUN

Question 13

Star Temperature Hierarchy

Answer 13

O blue/violet lots of heluim
B blue
A white strongest hydrogen lines
F yellow white
G yellow
K orange weak hydro
M red weak hydro
0-9, lowest being hottest

Question 14

Luminosity

Answer 14

-intrinsic absolute brightness

Question 15

Apparent Brightness

Answer 15

-energy per unit area per time depends on distance

Question 16

Photometry

Answer 16

• B Filters and V filters

- Blue and red respectively. use the filters to find temp. ratios

Question 17

Stefan-Boltzmann Law

Answer 17

-luminosity proportional to the radius squared times the temperature to the power of 4

Question 18

Hertzsprung-Russell Diagram

Answer 18

• luminosity and temperature
• cool faint, hot bright
• top left high temp and luminosity; bottom right low temp and luminosity

Question 19

Luminosity Classes

Answer 19

• measure absorption spectra
• wider denser smaller radius
• narrow less dense large radius

Question 20

Bootstrapping Distance Approach

Answer 20

• radar
• spectroscopic parallax and photometery
• stellar parallax
• Cepheid Period Luminosity

Question 21

Spectroscopic Parallax

Answer 21

-not really parallax
-use the parallax and spectral type to find luminosity class. calculate distance
-period proportional to brightness
(Henrietta Leavitt)

Question 22

Binary Star Systems

Answer 22

-stars orbiting each other

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