Pulsating Variable Stars Welcome J Leon Wilde BGSU

Pulsating Variable Stars Welcome J Leon Wilde BGSU March 31 st 2005

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

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

Pulsating Variable Stars History

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

Pulsating Variable Stars PVS Physics

Pulsating Variable Stars PVS Physics • Classes:

Pulsating Variable Stars Who cares? • Very large luminosities • Distance calibrations

Pulsating Variable Stars Recent work? • Polaris! • Period – 1844 -2004, increase 4. 5 s/year – 1963 -1966, brief hiatus • Magnitude – Prior to 1963, 0. 1 mag – After 1966, sharp decline, 0. 05 mag • Seems to no longer pulsate

Pulsating Variable Stars Thanks and references • Thanks! • References: – http: //www. adsabs. harvard. edu/ – http: //zebu. uoregon. edu/~soper/Milky. Way/cepheid. html – http: //www. cartage. org. lb/en/themes/Sciences/Astronomy/Thestar s/energyproduct/Energy. Transport. htm – http: //antwrp. gsfc. nasa. gov/apod/ap 981027. 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/v 117 n 828/ 205015/205015. html • Powerpoint presentation available @: http: //www. wildealien. com/astro/vst. ppt