Astrophysics SL

mercury
venus
earth
mars
(asteroid belt)
jupiter
saturn
uranus
neptune

grouping of large stars that have gravitational interaction/attraction with each other and are relatively close to one another

two stars orbiting a common centre

the remnant of white dwarf after it has cooled down
very low luminosity

a singularity in space time
the end result of the revolution of a very massive star

a star of variable luminosity with well-defined period
the period is related to the absolute luminosity of the star and so can be used to estimate the distance to the star

a group of stars in a recognizable pattern that appear to be near each other in space when observed from the earth

matter that is too cold to radiate
its existence is inferred from techniques other than direct visual observation

collection of very large number of stars mutually attracting one another through the gravitational force and staying together

a normal star that is undergoing nuclear fusion of hydrogen to helium

the end result of the explosion of a red supergiant
a very small star with high density
star consist almost entirely of neutrons, hence its name

the ejected envelope of a red giant star

a main-sequence star evolves into a red giant
there are nuclear reactions involving the fusion of helium into heavier elements

the end result of the explosion of a red giant
small, dense star in which no nuclear reactions take place
although hot, small size gives very low luminosity

power radiated by a star

received power per unit area

change in position of a star in the sky at times six months apart

higher the temperature, the lower the wavelengths at which most of the energy is radiated

a star of known luminosity

*period can be used to find luminosity, which can then find apparent brightness, which finds distance. hence, relative distance can be measured using standard candles.

mass at which electron degeneracy pressure prevents the further collapse of the core, star will become a stable white dwarf

mass at which star can maintain stability and become a neutron star

velocity of recession is directly proportional to distance
more distant the galaxy, the faster it moves away from us

relative brightness as seen from the earth

relative brightness as seen 10 pc from the star

amount of matter per unit volume space that could create enough gravitational pull so that the universe will continue to expand, yet slow down to a certain point

emission spectrum of the star contains being absorbed by

1. it does not come from any particular spot in the sky but rather fills all space
2. radiation detected was remnant of the hot explosion at the beginning of time
* When the universe is expanding, it gave off EM waves and these waves have become thin wavelength as the space-time expands to the present time

rocky substance that orbits around the sun

red-shift is a result of Doppler effect and proves that universe is expanding and galaxies are moving away. therefore universe is not static.

infinite, uniform, static

if angular position of a star is measured before and after 6 months, the two position will be different relative to a background of a very distant star.

if universe is infinite, there will be infinite amount of energy. but if the universe is uniform, then each point will receive infinite energy uniformly therefore the sky will be bright.

a small body made of mainly ice and dust, orbiting the sun in an elliptical orbit
displays atmosphere when close to sun but atmosphere no longer present when far from sun