1. Copy and Answer in NB 1.What are the three layers of the suns atmosphere? 2.What produces auroras? 3.What are sunspots and why are they dark? 4.Describe solar flares and prominences. 5.How does the sun produce energy and where does this process take place?

2. Measuring Stars What is the fate of our sun and other stars?

3. Star Groups Constellation – Group of stars that form a pattern in the sky that resembles an animal or mythological character Seen at different times of the year Orions Belt

4. Star Groups Cluster – Group of stars gravitationally bound to each other Some are densely packed (globular) and some are loosely packed (open)

5. Star Groups Binary Star – two stars that are gravitationally bound to each other and orbit a common center of mass (ex: Sirius) – Can appear to be one star to the human eye

6. Units of Distance Light Year (ly) – Distance light travels in one year – 9.461 x 10 12 km Parsec (pc) – 3.26 ly or 3.086 x 10 13 km

7. Parallax The apparent shift in position caused by the motion of the observer The closer the star, the larger the shift

8. Basic Properties of Stars Apparent Magnitude – How bright a star appears to be Absolute Magnitude – Brightness an object would have if it were placed at a distance of 10pc – Calculates for equal distance – Can only be used if stars distance is known

10. Basic Properties of Stars Luminosity – Energy output from the surface of a star per second – Measured in Watts – Must know distance of star and apparent magnitude

11. Hertzsprung Russell Diagram H-R Diagram – graph that organizes stellar characteristics (By temp and luminosity) Main Sequence – runs diagonally from the upper left corner, hot luminous stars, to lower right corner, cool dim stars – 90% of all stars, including the Sun

13. Hertzsprung Russell Diagram Red Giant – Cool, Luminous Star – Upper Right hand corner of H-R diagram White Dwarf – Dim, hot star – Lower Left hand corner of H-R diagram