AST 101 Lecture Notes - Lecture 11: Hipparcos, Multicolor, Photosphere
Document Summary
All the things that happen in the solar atmosphere. Sunspots appear dark because they are cooler than the rest of the photosphere. Solar cycle is the rise and fall of the number of sunspots - sunspot cycle. Light is all the information we get from stars. Two stars, altair and minar, have the ame apparent brightness however, altair is twice as far away as minar. M=absolute magnitude: magnitude star would have at a distance of 10 pc. Brighter stars have smaller magnitude values i. e. a 6th magnitude star is brighter than a 15th magnitude star. The star vega (alpha lyrae) is the reference star for the magnitude system. Vega magnitude = 0 in all filters. Vega is the 3rd brightest star in the sky. To convert e. g. observed brightness to luminosity we need to know the distance. Determine distances to stars using stellar parallax (winking with different to the source eyes with finger in front of your face)
