Event Details

Greta Helmel will present her honors thesis, "Recent Evolution of the Eta Carinae Supernova Imposter System."

The supernova imposter Eta Carinae and its surrounding Homunculus reflection nebula have been of great interest for the last several decades. As the most massive star known in our Galaxy, this object is of particular importance in understanding high mass loss episodes and final stages in the evolution of similarly massive stars. Using the most recent set of spectra from the Hubble Space Telescope STIS/CCD, we investigate changes in the behavior of the central star from 2012 to 2018, which indicate an overall brightening and a related decrease in the stellar wind density. Overall, the star appears to be slowing its development in comparison to the rapid changes it exhibited between 2004 and 2010. We also quantify the evolution of the Homunculus nebula, , determining a precise expansion rate and age estimate based on 18 years of STIS observations, one of the longest temporal baselines ever produced for this object using a single instrument. 

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