11:10:09 Our Milky Way Galaxy and Other Galaxies

11:10:09 Our Milky - 08:35:00 Whatwentwrong Absorptionbydust o Flux o o o MappingOuttheGalaxy

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Our Milky Way Galaxy and Other Galaxies 10/11/2009 08:35:00 What went wrong? Absorption by dust o Flux o Absorption reduces Flux o Dust absorbs more in blue than in red o Use colors to sort out dust from distance Mapping Out the Galaxy What do we know about the different parts of our Milky Way Galaxy o Need distances to figure out how big it is and where things are Key Elements o Parallax only works for nearby stars o “Standard Candles” – objects of known luminosity. Observe flux, then  get distance o Want them to be intrinsically bright and good standards. Cepheid  variable stars standard candles of choice Pulsating Variable Stars These stars regularly expand and contract Like a big spring Change in size o Change in luminosity Cepheid variable stars with longer periods have greater luminosities (P-L  relation) How to use the Cepheid P-L Relation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/17/2011 for the course ISP 205 taught by Professor Donahue during the Fall '08 term at Michigan State University.

Page1 / 4

11:10:09 Our Milky - 08:35:00 Whatwentwrong Absorptionbydust o Flux o o o MappingOuttheGalaxy

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online