Upper Limits to Long-Term Variability of Solar-Type Stars

Professor Emeritus Steve Spangler

Abstract: There have been a number of events in the geological history of the Earth in which the mean temperature of the Earth was substantially higher or lower than present.  These events were not caused by human carbon dioxide emission.  One possible mechanism is low-level variations in the luminosity of the Sun.  In this project, I obtain an upper limit to such variations by measuring the range in luminosity of Solar-type stars in the open star cluster Messier 67.  The present upper limit is not stringent, but the method could be easily improved with existing data, yielding significant upper limits or an actual detection.

To participate in this event virtually via Zoom, go to https://uiowa.zoom.us/j/91226290867?pwd=mCGHMM8C7GwPxGAVr2pk5tIhboh97E.1.