Star Systems and Galaxies Section 15-4 Star Systems and Galaxies
Star systems and Planets More than half of all stars are members of groups of two or more stars called star systems
Star systems and Planets Double and Triple Stars Binary System – two or more stars Eclipsing Binary System – where one star covers the other Found by looking at star “wobble” from gravitational pull of other star Planets around other stars Also found by looking at “wobble” caused by gravity
Galaxies Irregular Galaxies Spiral Elliptical Galaxies Three types of Galaxies: spiral, elliptical, and irregular Spiral Pinwheel shape Elliptical Galaxies Shaped like a flattened ball Irregular Galaxies No particular shape, usually a cloud (very large nebula)