• Shuffle
Toggle On
Toggle Off
• Alphabetize
Toggle On
Toggle Off
• Front First
Toggle On
Toggle Off
• Both Sides
Toggle On
Toggle Off
Toggle On
Toggle Off
Front

### How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

Play button

Play button

Progress

1/14

Click to flip

### 14 Cards in this Set

• Front
• Back
 parallax =apparent shift of nearby objects relative to background objects, due to changing perspective of observer closer the object=greater the shift smaller the angle, the larger the distance d=1/p closest star to us Proxima Centauri in the Alpha Centauri star system 4.3 ly away stellar motions radial motion= motion towards or away from Earth (detected thru doppler shifts in light) Transverse motion= motion across our line of sight proper motion: angular motion of a star across line of sight barnard's star moved 228 ft in 22 years proper motion of 10.3 ft/yr luminosity energy emitted by an object in a unit amount of time intrinsic propert= does not depend on observers location or motion relative to star Flux =apparent brightness energy per unit area perpendicular to path of light at Earth (intensity of light) not intrinsic. closer you are to object, the brighter it will appear flux related to distance @1 pc away, light pass thru 1 unit area @ 2 pc away, same amount of light passes thru 4 unit area (each unit recieves 1/4 as much energy) @3 pc away, same amount of light passes thru 9 unit area (each area reieves 1/9 as much energy) f~1/ d^2 inverse square of light flux directly related to luminosity (more luminous, brighter it will appear) Flux inversely related to distance, squared (farther the star, the dimmer it will appear) ..if we know flux and distance, can measure lumionsity magnitude scale hipparchus: compared brightness of stars and ranked them. brightest=1st class, faintest=6th class apparent visual magnitude: brighter the star, the lower the magnitude. possible for negative magnitude. decrease of 5=increase in flux by factor of 100 absolute v. apparent magnitude absolute= intrinsic visual magnitude of a star (analogous to luminosity). property of a star, will not change regardless of distance or motion apparent= visual magnitude of a star as it appears from Earth (analogous to Earth). would change if start were moved to different location apparent=absolute if star located 10 pc away filters cool star: more yellow light than blue warm star: rougly equal amounts of blue and yellow light hot star: more blue light than yellow Hydrogen Balmer lines A stars= strongest Balmer lines Q stars= weakest Balmer lines spectral classification O B A F G K M O= hottest M= coolest 10 subclasses (0-9; 0 is slightly hotter, 9 is slightly cooler) sun is G2 HR diagram white dwarfs= hotter, lower luminosity stars red giants= cool, red stars with high luminosity