stars and galaxies definitions

secular parallax

________________ occurs because of the Sun’ s motion through the galaxy, which as about 20 km/s. When added up over long periods, it can be used like Annual Parallax to determine the distance to stars. it aids in distance estimation by exploiting the suns motion through the galaxy.occurs because of the Sun’ s motion through the galaxy, which as about 20 km/s. When added up over long periods, it can be used like Annual Parallax to determine the distance to stars.

effective temperature

(Teff = [ L* / ( 4 p R* 2 s ) ]1/4) The ___________ makes this equation true. ___________ is the temperature of a black body emitting the same luminosity per surface area as the star.

Stefan boltz Law

energy emitted per unit of a black body is proportional to the fourth power of the absolute temperature (T⁴).

wiens law

maximum wavelength= wiens constant/absolute temperature

Increased temperature= shorter wavelengths

Radial Velocity

space motion

The actual True Vector velocity of the star with respect to the Sun. This can only be determined if we know the Radial Motion, the Proper Motion and the Distance of the star from the Sun. (Measured in km/s)

zeeman effect

_______causes spectral line splitting due to the influence of strong magnetic fields.

Luminosity (L)

=effective temperature(T^4)xstefan boltzmann constant (σ)x 4πR²(radius of the star)

So the ___________ of a star is determined by its effective temperature and surface area

___________ is the total energy radiated by a star per second across all wavelengths.

Babylonians

developed algebra, Perpetuated the calendar choices of the Sumerians,

Hipparchus

Developed the Stellar Magnitude Scale—produced a Star catalog— Measured the distances to the Sun and Moon—discovered the 26,000 year precession of the Earth’s axis of rotation—argued against the Heliocentric theory. The greatest observational astronomer in antiquity

Democritus and Leuc

Founders of the atomic theory and the vacuum

The Pythagoreans:

Separated Science and Philosophy • Suggested the Earth rotated on its axis, and possibly was not the center of the Universe…

Plato

founded the first university

Aristotle

Founded the current scientific disciplines—founded his own Univ.— big contributions in biology—argued the Earth was a sphere—argued against a heliocentric theory because of the lack of an observable stellar parallax…

Summerians

Originated the 7-day week and the roots of the 24-hour day and 60 minute hour…

Egyptians

Used a 10-day week. Developed geometry

Copernicus

: Re-introduced the Heliocentric Theory—described the Solar System with the correct Sidereal periods.

Tycho

complied large amount of observations of space 

Kepler

inherritted tychos data to create the 3 laws of planetary motion

Keplers first law (of planetary motion)

planetary orbits are ellipses with the sun at the focus

Keplers second law

equal areas are swept out in equal time intervals, dA/dt=L/(2m)

dA/dt= change in area/period of time= areal velocity, the rate in which the area is swept out

L:angular momentum

m:mass of planet

Keplers third law

(M1-M2)P²=a³

P is the sidereal period

a is the semi major axis

M-mass

Galileo

discovered the 4 jupiter moons, the crescent phases of venus, introduced the scientific method

law of universal gravitation

F=G(m1)(m2)/r²

Newtons first law

law of inertia

newtons second law

f=ma

newtons third law

every action has an equal and opposite reaction

proportional

the luminosity is _________ to the surface area(radius²) and the Temperature^4

rotational broadening

when a star's rotation causes its spectral lines to widen by shifting wavelengths due to the Doppler effect. Because one side of a rotating star moves toward us and the other moves away, light from the approaching side is blue-shifted and light from the receding side is red-shifted

100

a difference of 5 magnitudes means a factor of _____ in brightness

approaching

higher labratory wavelength and lower observed indicates the source is

thermal broadening

_______ is due to the doppler shift from any temp above absolute zero

Collisional broadening

due to high pressure, resulting in frequent collisions of emitting atoms.

visual binary star systems

stars are clearly seen(maximum info)

astrometric

only one star is seen, but it moves in an ascillatory way

spectroscopic

when viewed on the edge the spectral lines are are alternatively doppler shifted in orbit

spectrum binary star system

the light shows two incompatible spectra

eclipsing binary star systems

the intensity of the light dims as stars eclipse, these are alse spectroscopic

eudoxus

A contemporary of Plato and Aristotle—early developments of “Mechanics” in physics

Aristarchus

First serious proponent of the Heliocentric theory

Ptolemy

Passed down to us much of what we know about the earlier contributions. Set down the principals of celestial navigation and Astrology

centi

1×10^-2

deci

1×10^-1

milli

1×10^-3

micro

1×10^-6

nano

1×10^-9

pico

1×10^-12

hecto

1×10²

kilo

1×10³

mega

1×10^6

giga

1×10^9

tera

1×10^12

peta

1×10^15

exa

1×10^18