PH1600: Introductory Astronomy Lecture 14: Stars: Single and Binary What is this?

PH1600: Introductory Astronomy Lecture 14: Star: Single and Binary Study: Chapter 11 in The Cosmos book Next Lecture: Star Clusters School: Michigan Technological University Professor: Robert Nemiroff Book: The Cosmos by Pasachoff & Filippenko Online Course WebCT pages: This class can be taken online ONLY, class attendance is not required!

You are responsible for…  Reading the book One chapter per “quiz period” Anything from that chapter can appear on quizzes or tests, even if I never mention them during my lecture(s) This quiz period covers Chapter 11  APODs posted during the semester APOD review every week during lecture  Completing the Quizzes Chapter 1, 2, 4, 6, 7, 8, &10 quizzes already due Chapter 11 quiz due next See WebCT at for detailshttp://courses.mtu.edu/

Stars: Distant Suns Henrietta Leavitt Calibrates the Stars Credit: AAVSO APOD: 2000 September 3

Stellar Spectral Types: OBAFGKM Credit & Copyright: KPNO 0.9-m Telescope, AURA, NOAO, NSF APOD: 2004 April 18

Orion Star Colors Credit and Copyright: David Malin APOD: 1998 August 29

Famous Stars  Sun  Polaris North star  Sirius  Betelgeuse  Alpha Centauri Proxima Centauri

Polaris: The North Star Credit & Copyright: Wally Pacholka APOD: 1999 October 6

Sirius: The Brightest Star in the Night Credit & Copyright: Juan Carlos Casado APOD: 2000 June 11

X-Rays From Sirius B Credit: NASA/ CXC/ SAO APOD: 2000 October 6

Resolving Mira Credit: M. Karovska (Harvard-Smithsonian CfA) et al., FOC, ESA, NASA APOD: 2001 January 21

A Giant Starspot on HD Credit & Copyright: K. Strassmeier (U. Wien), Coude Feed Telescope, AURA, NOAO, NSF APOD: 2003 November 2

Betelgeuse, Betelgeuse, Betelgeuse Credit: A. Dupree (CfA), R. Gilliland (STScI), NASA APOD: 1999 June 5

Simulated Supergiant Star Credit: B. Freytag, (U. Uppsala) APOD: 2000 December 22

Why Stars Twinkle Credit: Applied Optics Group (Imperial College), Herschel 4.2-m Telescope APOD: 2000 July 25

Inverse Square Law of Brightness

Example  Stars A and B are identical. Star B is at twice the distance of star A. How much brighter does star A appear than star B?  Use inverse square law: l A =k/r A 2 Also, l B =k/r B 2. Therefore l A /l B =(r B /r A ) 2 = 2 2 = 4.

Proxima Centauri: The Closest Star Credit & Copyright: David Malin, UK Schmidt Telescope, DSS, AAO APOD: 2002 July 15

Alpha Centauri: The Closest Star System Credit: 1-Meter Schmidt Telescope, ESO APOD: 2003 March 23

Binary Stars  Visual Binaries Can see two or more  Spectroscopic binaries Doppler color changes  Eclipsing Binaries Dark times  Astrometric Binaries Wobble

Albireo: A Bright and Beautiful Double Credit & Copyright: Richard Yandrick (Cosmicimage.com) APOD: 2005 August 30

The Big Dipper Cluster Credit & Copyright: Noel Carboni APOD: 2006 March 17

Mizar Binary Star Credit: J. Benson et al., NPOI Group, USNO, NRL APOD: 1997 February 19

Mira: The Wonderful Star Illustration Credit: M.Weiss(CXC) APOD: 2005 May 5

NGC 3132: The Eight Burst Nebula Credit: Hubble Heritage Team (AURA/STScI /NASA) APOD: 2003 September 13

An Intermediate Polar Binary System Illustration Credit & Copyright: Mark Garlick (Space-art) APOD: 2003 November 10