Astrophysics Vocab Physics IB

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Binary star
Two stars orbiting around a common center
Black dwarf
The remnant of a white dwarf after it has cooled down. It has a low luminosity.
Black hole
A singularity in space- time; the end result in the evolution of a massive star.
Brown dwarf
Gas and dust that did not reach high enough temperatures to initiate fusion, these objects continue to compact and cool down.
Cepheid variable
A star of variable luminosity. The luminosity increases sharply and falls of gently with a defined period; this can be used to estimate the distance to the star.
Clusters of galaxies
Galaxies close to each other and affecting each other gravitationally.
A small body of mainly ice and dust which orbits the sun elliptically.
A group of stars in a recognizable pattern that appear to be near each other in space.
Dark matter
Generic name for matter in space that is too cold to radiate and which is not observable by direct observation, we know it exists by techniques of observance.
A large collection of stars which mutually attract each other through gravitational forces.
Interstellar medium
Gases, mainly hydrogen and helium, and dust grains that fill the space between stars. This has a very low density.
Main sequence star
A normal star that is undergoing the nuclear fusion of hydrogen into helium atoms (like our sun).
Neutron star
The end result of the explosion of a red giant which throws off mass and results in this smaller, very dense star. It consists almost entirely of neutrons and has a core of immense pressure and density.
The sudden increase in luminosity of a white dwarf caused by material from a nearby star falling into the white dwarf.
Planetary nebula
the ejected envelope of a red giant star.
a rapidly rotating neutron star emitting electromagnetic radiation in the radio region. They have strong magnetic fields.
The powerful energy emitters and cores of young galaxies.
Red dwarf
A very small, reddish star with low temperature.
Red giant
A very large, reddish star which results from the evolution of a main sequence star; it fuses helium into heavier elements.
Stellar cluster
A group of starts that are physically near each other in space as a result of a gas cloud collapsing.
The explosion of a red supergiant star (releases immense amount of energy).
White dwarf
Results when a red giant throws off mass and leaves behind a very small, dense star in which no nuclear reaction takes place. It is hot but with a low luminosity.
A small unformed planet, rocky
Categories: Astrophysics