The Study of Light Variability in a Sample of Proto-Planetary Nebulae Candidates

Faculty Sponsor

Bruce Hrivnak


Arts and Sciences


Department of Physics and Astronomy

ORCID Identifier(s)


Presentation Type

Poster Presentation

Symposium Date

Summer 7-28-2016


Proto-planetary nebulae (PPN) are stars like our sun that are in the late stages of stellar evolution. This stage comes after the red giant stage and before the planetary nebula stage and is characterized by pulsations. The focus of the research this summer is largely on taking observations of ~25 PPN candidates here at the Valparaiso University Observatory (VUO), and searching for potential periods in the light data collected using a program called Period04. The data set that we use, and are continually adding to, began in 2008 with the arrival of the new CCD camera on campus. For my independent project, I am refining my initial findings of periodicity on the five stars from last summer to get a better sense of their light variations and adding to the list two additional objects that we observe from the VUO. The periods of these objects can be anywhere from 50 to 200 days in length, if they are PPN. Any longer than that and they can be classified as other types of variable stars, such as long period variables. From the study of these stars we can find out more about the mechanism of the pulsation, and each star’s independent characteristics. Initial findings show periodicity in five of the seven stars, ranging from 50 days to a couple of years in length. This research is funded through grants from the National Science Foundation and the Indiana Space Grant Consortium.

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