1. Pulsating Variable Stars

2. Pulsating Variable Stars Overview History of discovery What are pulsating variable stars? Why are they important? Any recent works?

3. Pulsating Variable Stars History 1595 – David Fabricius –o Ceti, 11 months 1784 – John Goodricke –d Cephei, 5d, 8h, 48min ~1912 – Henrietta Leavitt

4. Pulsating Variable Stars History

5. Pulsating Variable Stars PVS Physics Periodic luminosity changes Radial vs Nonradial Pressure wave estimation:

9. Pulsating Variable Stars PVS Physics

10. Classes:

11. Pulsating Variable Stars Who cares? Very large luminosities Distance calibrations

12. Pulsating Variable Stars Polaris! Period –1844-2004, increase 4.5s/year –1963-1966, brief hiatus Magnitude –Prior to 1963, 0.1mag –After 1966, sharp decline, 0.05mag Seems to no longer pulsate

13. Pulsating Variable Stars references References: –http://www.adsabs.harvard.edu/ –http://zebu.uoregon.edu/~soper/MilkyWay/cepheid.html –http://www.cartage.org.lb/en/themes/Sciences/Astronomy/Thestar s/energyproduct/EnergyTransport/EnergyTransport.htm –http://antwrp.gsfc.nasa.gov/apod/ap981027.html –http://astro.wsu.edu/worthey/astro/html/lec-women.html –http://www.if.ufrgs.br/oei/stars/aglom/clusters.htm –Polaris article: http://www.journals.uchicago.edu/PASP/journal/issues/v117n828/ 205015/205015.html