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50 terms

astronomy chapter 17

chapter 17
STUDY
PLAY
a nearby star has aparallax of .2 arc seconds, what is its distance
5 parsecs
what is proper motion
it is the annual apparent motion of a star across the sky
which statement about stellar motion is incorrect
like parallax, proper motion is measured over intervals of exactly six months
which of the following best describes the size and distance relationship of our sun and the nearest star
two golf balls separated by 100 kilometers
if a star has a parallax of .05, then its distance in light years is about
65 light years away
if a star is found by spectoscopic observations to be about 500 parsecs distant, its parallax is
.002"
hipparcos observations have given us good data on stars out to about
200 parsecs
about how many stars has hipparcos given us accurate distance data on
a millon, those with parallaxes of .005" or larger
procyon lies about 13 light years distant, thus its parallax is about
.25"
in order to turn a star's proper motion into its space velocity, we must also know
the distance and radial velocity
if a star appears to move back and forth relative to other stars over a six-month period, this motion is due to the star's
parallax shift
if a star appears to move relatie to other stars over a one year period, this motion is due to the star's
transverse motion or true space motion
what is the absolute magnitude of our sun
+4.8
the absolute magnitude of a star is its brightness as seen from a distance of...
ten parsecs
perhaps the greatest of the greek astronomers____compiled the first catalog of stars accurately measured their positions, and defined the basic system of stella brigthness
hipparchus
in comparing first magnitude Deneb will second magnitude Polaris, we find that....
Deneb appears 2.5 times brighter to us than does Polaris
at the distance of jupiter (6 times further away from the sun than the earth) the amount of sunligth received per square centimeter different by waht factor
36 times less (inverse sqaure law)
Star A and star B have an apparent magnitude of 4.0 but star A has an absolute magnitude of 1.0 and star B has an absolute maginuted of 7.0 then...
star A and star B appear to have the same brightness, but actually star A is brighter than star B
star A snd B have the same apparent magnitude of 7.0. but star A is at a distance of 15 pc and star B is at a distance of 30 pc...then
star A and B appear to have the same brigthness, but actually star B is brighter thans star A
star A and B both have an absolute magnitude of 2.0 but star A is at a distance of 50 pc and star B is at a distance of 20 pc...then
star B appears brighter than star A, but actually star A and B are the same brightness
star A and star B have an absolute magnitude of 2.0 but star A has an apparent magnitude of 5.0 and star B of 7.0..then
star A appears brighter than star b, BUT in actuallity both have the same broightness
star A has an absolute magnitude of 2.5 and star B an apparent magnitude of 2.5, but star A is a main sequence star an star B is a red giant...then
its impossible to dtermine how bright they are given the information
what are the two most important intrinsinc properties used to classify stars
luminosity and surface temperature
what physical property of a star does the spectral type measure
temperature
the star's color index is a quick way of determining its
temperature
the most famous G type star is
the sun
star A is a main sequence star of spectral type F2 and star B is a white dwarf of spectral type..then
star B is hotter than star A
star A is a main sequence star of spectral type G5 and star B is a red giant of spectral type k2..THEN
star A is hotter than star B
stars that have masses similar to the sun's and sizes similar to the earth are...
white dwarfs
compared to the size of the sun, between what range of sizes are most stars found
.01to 100 solar radii
on the H-R diagram , the sun lies
about the middle of the main sequence
which of the following is th emost commno type of star
low mass main sequence
the H-R diagaram plots ______ against the spectral type or temperature
luminosity or absolute magnitude
how might th emost common occurring stars be described, based on our stellar neighbrohood?
M, main sequence
on the HR diagram, red supergiants like Betelguese lie
at the top right
on the HR diagram white dwarfs like Sirius B and Procyon B lie
at the lower left
in the HR diagram, the bright blue-white stars that dominate the naked eye sky lie to the ...
top left
having nothing to do with trigonometry ____parallaxes use the width or absorption lines to estimate the stars luminosity and size and distance
spectroscopic
in general the narrower the spectral line of a star
the bigger the star is
upon what data do measurments of sizes of eclipsing binaries depend
their dopler shifts and durations of stages of their eclipses
which type of binary can have sizes measured directly by photometry
eclipsing
in what range of masses are most stars found
.1-100 solar masses
in a visual binary system with circular orbits, if in 20 yrs the two stars position angles have shifted 30 degree, the pair's period must be
240 years
in a spectroscopic binary system, the star showing the larger blue shift is...
less massive and approaching us at this moment
in a spectroscopic binary, if a pair shows a combined set of line tonight, but a maximum split two nights later , its orbital period must be
8 days
what is the single most important characteristic in determening the course of a star's evolution
mass
what is the typical main sequence lifetime of a M-type star
a trillion years
what os th etypicall lifetime of a G-type star
10 billion years
what is the typical life time of a B type star
20 milion years
for a star 10 solar masses, its main sequence life span will be
only 1/1000th of the sun