Searching for Periodicity in 6 Carbon-rich Protoplanetary Nebula

Faculty Sponsor

Bruce J. Hrivnak


Arts and Sciences



Presentation Type

Poster Presentation

Symposium Date

Spring 4-28-2022


Protoplanetary-nebula (PPNe) are stars in the stage of stellar evolution that falls between the asymptotic giant branch and planetary nebula (PNe) stages. Most PPNe display cyclical variations in their brightness due to pulsations. In an earlier study of 12 carbon-rich PPNe, periods were found for all of the objects, ranging from 38 to 153 days (Hrivnak et al. 2010, ApJ 709, 1042). In this present study, we have analyzed newer and more precise data for 6 of these objects. Observations were obtained at the Valparaiso University Observatory (2008 to 2018) in the V and r filters. In addition, we have used observations from the All-Sky Automated Survey for Supernova (ASAS-SN; 2016 to 2021) first in the V and then in the g filter. While these later cover shorter intervals of time, they have much denser coverage. These datasets separately and in combinations were analyzed using PERIOD04. Primary and secondary periods were found for each object. The results of the primary periods are generally similar to those of the earlier study. We also investigated possible period changes. This research is supported by a grant from the National Science Foundation (1413660).

Biographical Information about Author(s)

I am a current Junior studying Physics and Political Science with a minor in Mathematics. The research presented with this poster started in the summer of 2021 and continued till February of 2022 under mentor-ship by Dr. Bruce Hrivnak. I currently plan to go onto graduate school for a PhD in Astrophysics studying the galactic interaction and evolution.

This document is currently not available here.