* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download ASTR101 Unit 10 Assessment Answer Key 1. Mass, luminosity, size
History of Solar System formation and evolution hypotheses wikipedia , lookup
Star of Bethlehem wikipedia , lookup
Corona Borealis wikipedia , lookup
International Ultraviolet Explorer wikipedia , lookup
Auriga (constellation) wikipedia , lookup
Cassiopeia (constellation) wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Corona Australis wikipedia , lookup
Extraterrestrial life wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Rare Earth hypothesis wikipedia , lookup
Observational astronomy wikipedia , lookup
Dialogue Concerning the Two Chief World Systems wikipedia , lookup
Type II supernova wikipedia , lookup
Future of an expanding universe wikipedia , lookup
Dyson sphere wikipedia , lookup
Canis Major wikipedia , lookup
Stellar kinematics wikipedia , lookup
Perseus (constellation) wikipedia , lookup
Planetary habitability wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Stellar evolution wikipedia , lookup
Astronomical unit wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Corvus (constellation) wikipedia , lookup
ASTR101 Unit 10 Assessment Answer Key 1. Mass, luminosity, size, surface temperature, and age. Ordinary stars range in mass from about 60 solar masses to about 1/12 solar mass, in luminosity from about 1,000,000 to 1/10,000 solar luminosities, in radius from about 1,000 to 1/10 solar radii, in surface temperature from about 35,000 to 3,000 K, and in age, from about 13 billion years to stars that are just now being born. 2. Luminosity is the amount of energy the star emits per second while apparent brightness depends on how much of that energy reaches earth, that is, on the distance to the star. 3. The distance to the star. As the earth moves in its orbit around the sun, the nearby stars shift their positions in the sky with respect to the more distant stars, with the amount of shift being greatest for the nearest stars. Knowing the amount of the shift and the distance between the sun and earth, the distance to the star can be determined by geometry. 4. The apparent brightness of a star decreases with the square of the distance to the star (the inverse-square law). Thus if the luminosity (energy emitted) is known and the apparent brightness (energy reaching earth) is measured, the distance can be calculated. 5. Apparent brightness decreases with the square of the distance, so if two stars have the same luminosity and one is three times farther away, the closed star will have nine times the apparent brightness. If two stars are at the same distance and one is emitting three times as much energy, the apparent brightness of the more luminous star will be three times greater. Saylor URL: http://www.saylor.org/ASTR101 Subunit 10.3 The Saylor Foundation Saylor.org Page 1 of 2 6. Saylor URL: http://www.saylor.org/ASTR101 Subunit 10.3 The Saylor Foundation Saylor.org Page 2 of 2