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The Universe Beyond . By; Amber Self. Stars. An Astronomer studies starlight. Stars are classified by 3 colors and temperature. Blue ( Rigel ) is hot, yellow is medium, and red (Betelgeuse) is cool. Composition of stars.
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The Universe Beyond By; Amber Self
Stars • An Astronomer studies starlight. • Stars are classified by 3 colors and temperature. • Blue (Rigel) is hot, yellow is medium, and red (Betelgeuse) is cool.
Composition of stars • The rainbow colors that are produced when white light passes through a prism spectrograph. • A spectrograph is a prism shaped object that helps to show spectrum. • A continuous spectrum is when the spectrum shows off all of the colors. • The surface of a star gives off a continuous spectrum but the light we se passes through the stars atmosphere.
Classifying stars • Stars were once classified by letters such as type A, stars that had very noticeable hydrogen patterns, and the rest of the stars were classified as type B stars. • Stars are now classified by temperature. Class Color surface temp.( C) elements ex. Of stars O Blue above 30,000 helium 10 lacerate B Blue-white 10,000-30,000 helium & hydrogen Rigel, Spica A blue white 7,000-10,000 hydrogen Vega, Sirius F yellow-white 6,000-7,500 hydrogen canopus G yellow 5,000-6,000 calcium the sun K orange 3,000-5,000 calcium arcturus M Red less than 3,500 molecules Betelgeuse
How Bright is that star? • How bright a star looks or appears is called apparent magnitude. • Astronomers use a star’s apparent magnitude and it’s distance from Earth to calculate its absolute magnitude. • Absolute magnitude is the actual brightness of a star.
Distance to the stars • Astronomers use light years to find the distance a star is from Earth. • A light year is the distance that light travels in one year. • Light travels about 9.5 trillion kilometers a year. • Using parallax and simple trigonometry astronomers can find the actual distance to the stars that are close to earth. • Parallax is an apparent shift in the position of an object when viewed from different locations
The H-R Diagram • The H-R diagram is a graph showing the relationship between a star’s surface temperature and it’s absolute magnitude. • The main sequence is a diagonal pattern of stars on the H-R diagram. • The red giant is a star that expands and cools once it runs out of hydrogen fuel. • The white dwarf is a small, hot star near the end of its life otherwise known as the leftover center of an old star.
When stars get old • Supernova is basically the death of a large star by explosion. • A neutron star is a star in which all the particles have become neutrons; the collapsed remains of a supernova. • If a neutron star is spinning it’s called a pulsar. • A black hole is an object with move than three solar masses squeezed into a ball only 10 km across whose gravity is so strong that not even light can escape .
Galaxies • Galaxies are large groupings of stars in space. • Spiral Galaxies have a bulge at the center and very distinctive spiral arms. • Elliptical Galaxies have very bright centers and very little dust and gas. • Irregular Galaxies are galaxies that don’t fit into any other class. • To the right is an example of a spiral galaxy.
Contents of galaxies • Nebulas are giant clouds of dust and gas. • Nebula is also the Latin word for ‘cloud’. • Globular Clusters are groups of older stars. • There may be 20,000-100,000 stars in average in a globular cluster. • Open Clusters are groups of stars that are usually located along the spiral disk of a galaxy. • A Quasar is a star-like source of light that is extremely far away. • A Quasar is also one of the most powerful energy sources in the universe.
