Unit 10 & 11 review

nebula

A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases.

red supergiant

A red supergiant is an aging giant star that has consumed its core's supply of hydrogen fuel. Helium has accumulated in the core, and hydrogen is now undergoing nuclear fusion in the outer shells. These shells then expand, and the now cooler star takes on a red color. They are the largest known

supernova

A supernova is an astronomical event that occurs during the last stellar evolutionary stages of a massive star's life, whose dramatic and catastrophic destruction is marked by one final titanic explosion.

white dwarf

A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to that of the Sun, while its volume is comparable to that of Earth

elliptical galaxy

An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. Unlike flat spiral galaxies with organization and structure, they are more three-dimensional, without much structure, and their stars are in somewhat random orbits around the center.

irregular galaxy

Having a lot of gas and dust means that these galaxies have a lot of star formation going on within them. This can make them very bright. The Large and Small Magellanic Clouds are examples of irregular galaxies. They are two small galaxies which orbit around our own Milky Way Galaxy

neutron star

Neutron stars are created when giant stars die in supernovas and their cores collapse, with the protons and electrons essentially melting into each other to form neutrons.

Hertzsprung Russell Diagram

The Hertzsprung-Russell diagram, abbreviated H-R diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures

milky way galaxy

The Milky Way is the galaxy that contains our Solar System. The descriptive "milky" is derived from the appearance from Earth of the galaxy - a band of light seen in the night sky formed from stars .

sun

The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process.

protostar

a contracting mass of gas that represents an early stage in the formation of a star, before nucleosynthesis has begun.

spiral galaxy

a galaxy in which the stars and gas clouds are concentrated mainly in one or more spiral arms

black hole

a region of space having a gravitational field so intense that no matter or radiation can escape

planetary nebula

a ring-shaped nebula formed by an expanding shell of gas around an aging star.

main sequence

a series of star types to which most stars belong, represented on a Hertzsprung-Russell diagram as a continuous band extending from the upper left (hot, bright stars) to the lower right (cool, dim stars).

light years

a unit of astronomical distance equivalent to the distance that light travels in one year, which is 9.4607 × 1012 km (nearly 6 trillion miles).

red giant

a very large star of high luminosity and low surface temperature. Red giants are thought to be in a late stage of evolution when no hydrogen remains in the core to fuel nuclear fusion.

spectroscope

an apparatus for producing and recording spectra for examination.

redshift

the displacement of spectral lines toward longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects. This is interpreted as a Doppler shift that is proportional to the velocity of recession and thus to distance.

blueshift

the displacement of the spectrum to shorter wavelengths in the light coming from distant celestial objects moving toward the observer

luminosity

the intrinsic brightness of a celestial object (as distinct from its apparent brightness diminished by distance).

absolute magnitude

the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs.