Quiz 1 Flashcards
A unit of angular measuring, the distance travelled in one minute
Arc minute
A unit of angular measuring, the distance travelled in one second
Arc second
Approximate distance from the center of the earth to the center of the sun
Astronomical unit
The distance light travels in one year
Light year
A unit used to measure distances to stars and galaxies, equal to 3.26 light years. Stars in the suns neighborhood are this distance apart
Parsec
The apparent difference of an object as seen from different places, how stellar distances are measured
Stellar Parallax
The first to find reliable values for the distances to other stars from our sun using parallax
Friedrich Bessel
An arc around two foci, the shape of an orbit
Ellipse
Half of the axis running through the foci
Semi major axis
Half of the axis running through the center
Semi minor axis
the two reference points that help in drawing the ellipse
Foci
Formula for the area of a triangle
A=h(b)b/2
The power a number must be raised to in order to be another number
Logarithm
proposed that the sun was stationary in the center of the universe and the earth revolved around it
Nicolas Copernicus
known today for his theory of the solar system which is based on a stationary Earth round which the Moon and Sun revolve. Made observations of figures with 4 degree accuracy of arc w/o a telescope
Tycho Brahe
M=(y2-y1)/(x2-x1). Rise/run of a best fit line
Slope
3 x 10^8 meters per second
Speed of light
independent variable (time)
X axis
dependent variable (position, meters)
Y axis
Best estimate with + or - half of the range
Reporting uncertainty
Three laws: orbits are ellipses with the sun as a foci, the planet Is faster the closer to the sun, and the orbital period is the semi major axis cubed
Johannes Kepler
19.19 au away 25,559 km radius, 14.5 mass, 1.32 g/cm^3 density, hydrogen and helium, cloud temp 60k, 27 moons, receives 1/400 sun energy
Uranus
Atmosphere similar to Jupiter/Saturn (hydrogen helium methane), more water. Axial tilt almost in line with orbit. Magnetic field similar to Saturn tilted greatest. Largest moon has history. Ring system in 1977
5 things about Uranus
30.06 au away, 1/900 suns energy, 24,764 km radius, average density 1.64 g/cm^3, hydrogen and helium, cloud temp 60k, 13 moons
Neptune
Blue from methane, atmosphere and interior similar and has great dark spot, radiates more energy than received like Jupiter/Saturn, has dark rings, moons show geology
5 things about Neptune
Waves of the electromagnetic field carrying radiative energy
Electromagnetic wave
A model of an atom consisting of a nucleus and orbiting electrons
The Bohr atom
Energy radiated by a source that absorbs radiation
Black body radiation
A spectrum of rays defined by their heating effect
Thermal spectrum
The pattern of lines when light passes through from a star or other stellar body, where lines appear if the source emits specific rays.
Emission spectrum
Lines that appear on a spectrum if an absorbing item is in the way between a source
Absorption spectrum
Sun is 8 light minutes away from earth, Proxima Centauri is 4.31 ly, Polaris is 650
Basic properties of stars
The founder of quantum theory through his formulation of his radiation law
Max Planck
In pc is the inverse of the parallax angle in seconds of arc
Distance to a star
Stellar motion. Derived by broadening of spectral lines, consequence of the Doppler effect
Rotation
Stellar motion, can be determined by a straightforward application of the Doppler effect
Radial velocity
Stellar motion, trigonometry are needs to know the stellar distance and the star’s angular motion across the sky
Tangential velocity
About half of our stars are members of these systems, use of newtons derivation of Kepler’s third law to estimate the mass
Binary stars
Stars with identical spectra have identical masses
Spectral/mass relationship (or mass/luminosity)
Revealed by spectral analysis, absorption/emission lines indicate presence of various elements, width of line, degree of brightness, or darkness indicate relative abundance
Composition
Presence of this causes emission/absorption lines in spectra to split in 2 or more close lines. See an effect used to detect
Magnetic fields
formulated by Annie Jump Cannon, based on number and difference of spectral lines and temperature
OBAFGKM
A star of a given magnitude is 2.5 times brighter than a star of the next higher magnitude
Magnitude
