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ASTR Midterm 1
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Given distance to object and object's disk in degree
Asked to find diameter of object
convert degree to arcsec
Given semi-major axis of object orbiting the Sun
Asked to find sidereal period
Semi-major axis must be in AU
sidereal period in seconds
Given objects length (diameter) and angle it subtends
Asked to find distance to object
angle in arcsec
Given mass of object (or ratio of mass) and semi-major axis
Asked to find gravitational force
Mass in kg and radius in meters
Given force and object's mass
Asked to find acceleration
acceleration in meters/second
Given sidereal period and semi-major axis of exoplanet
Asked to find mass of star (allowed to assume mass of planet is negligible)
a (semi-major axis) in meters
P (sidereal period) in seconds
Given objects distance from Sun and perihelion and aphelion
Asked to find sidereal period
sidereal period in seconds
semi-major axis in AU
Given perihelion and aphelion
Asked to find eccentricity of object's orbit
e ⋅ a= semi-major axis - perihelion
a is semi-major axis in AU
Given exoplanet's mass and diameter
Asked to determine weight on planet
weight is force
most likely asked to compare and set up ratio
Given surface temperature star
Asked to wavelength star radiates the most energy
λ in meter
Given surface temperature and radius of star
Asked to find luminosity
L=4⋅(pi)⋅R²⋅σ⋅T
^{4}
R in meters
Given frequency of wave
Asked to find wavelenght
Given wavelength of wave or photon
Asked to find energy of wave or photon
Given frequency of wave or photon
Asked to find energy of wave of photon
Given semi-major axis and period of planetary satellite
Asked to find mass of planet (not satellite)
P is seconds
a in meters
Given stellar luminosity and semi-major of orbiting planet
Asked to find flux of star at planet
L in watts
d in meters
F in W/m
^{2}
Given observed wavelength and laboratory wavelength
Asked to determine is star is moving toward or away from observer
Δλ=λ
_{observed}
- λ
_{laboratory}
Δλ is positive it is a redshift (moving away)
Δλ is negative it is a blueshift (moving toward)
Given observed and laboratory wavelengths
Asked to determine velocity
_{}
Given diameter of telescope
Asked to find light gathering power
light gathering power = d
^{2 }
Given diameter of telescope and wavelength of light
Asked to find resolving power
θ=2.5×10
^{5}
(λ÷D)
θ in arcsec
λ in meters
D in meters
Given resolving power of telescope and distance to observable object
Asked to determine size of smallest features the telescope can resolve
α in arcsec
Given surface temperature
Asked to find flux
F = σT
^{4 }
F in W/m
^{2}
Given energy of wave or photon
Asked to find wavelength
Given luminosity and % mass converted to energy
Asked to determine mass that is converted to maintain luminosity
Three parts:
Part one
: Luminosity is measured in W which = J/s (convert is needed or just make connection)
Part Two
:
Part Three
: divide mass of part two by % mass
Given parallax
Asked to determine distance from us
p in arcsec
d in parsec
Given distance and proper motion
Asked to find tangential velocity
v
_{t}
= 4.74μd
μ in arcsec per year
d in km
v
_{t}
in km/s
Given observed and laboratory wavelength
Asked to find radial velocity
Given radial velocity and tangential velocity
Asked to find space velocity
Given apparent brightness compared to Sun's and distance
Asked to find luminosity of star
Given star's distance and comparative brightness to star seen without telescope
Asked for distance to be seen without telescope
Given apparent magnitude of star and two telescope diameters
Asked to determine magnitude of dimmest star seen through larger telescope
Two Parts:
Part One
: Compare light gathering power to get ratio of brightness between viewed stars
Part Two
:
Given apparent magnitude and parallax
Two parts:
Part One:
Part Two:
Given absolute magnitude of star (star
_{1}
) and a ratio of luminosity
Asked to find absolute magnitude of another star (star
_{2}
)
Given apparent magnitude and absolute magnitude
Asked to find distance to star
Given semi-major axis and sidereal period of binary star system
Asked to find sum of masses of two stars
Masses in solar mass
Given age of star cluster
Asked to find mass of turn off star
Author
nikachan
ID
305620
Card Set
ASTR Midterm 1
Description
Deriving formulas from given information
Updated
2015-07-24T01:07:27Z
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