AY 101 Lecture Notes - Lecture 19: Photosphere, Magnesium, Stellar Atmosphere
Document Summary
Introduction to stars; properties of the sun3/5/2018 5:59:00 pm. What do we mean by heavier elements : in principle, this means any chemical element having more than 2 protons in its nucleus ( heavier than helium ). In astronomy, such elements are collectively called metals : examples include, carbon, nitrogen, oxygen, sodium, magnesium, iron, nickel, etc. The sun is the only star close enough to us that we can see details on its surface. Most stars are point sources, or unresolved points of light: the spikes are not real but are caused by the veins that hold the secondary mirror in a reflecting telescope. In any picture of the sun, dark means less light, not no light. Sunspots are cooler regions on the solar surface, and they emit less light as a result: sunspots are magnetically-disturbed regions on the surface of the. Sun: observations of sunspots tell us that the sun rotates, the rotation is not a solid object.
