Ch 19-20

what method is used to measure distancese to nearby stars

• spectroscopy

• radar

• triangulation

• redshift analysis

what is the parallax of a star

• its brightness variation

• its spectral class

• half the shift in its position relative to distant stars

• the time it takes to orbit the galaxy

what does parsec measure

• star temperature

• time for starlight to reach earth

• distance of a star with a parallax of 1 arcsecond

• amount of dust in interstellar space

how many light-years are in a parsec

• 1.26

• 3.26

• 4.56

• 10.2

which mission extended parallax measurements to 30,000 light-years

• hipparcos

• kepler

• gaia

• spitzer

what star is the closest to earth beyond the sun

• sirius

• betelguese

• alpha centauri

• red dwarf over 1 parasec away

what are cepheids and RR lyrae stars

• white dwarfs

• binary stars

• pulsating variable stars

• brown dwarfs

what does the period-luminosity relation apply to

• RR lyrae stars

• cepheid variables

• all stars

• brown dwarfs

how far can cepheid variables help us measure distances

• 600 light-years

• 6,000 light-years

• 60 million light-years

• 600 million light-years

how can a spectrum help determine a star's distance

• by revealing its mass

• by identifying its motion

• by locating it on the H-R diagram to find luminosity

• by measuring parallax directly