2023 Annual Meeting of the APS Mid-Atlantic Section
Friday–Sunday, November 3–5, 2023;
University of Delaware, Newark, Delaware
Session F01: Poster Session
4:00 PM,
Saturday, November 4, 2023
University of Delaware
Room: ISE Lab (ground floor)
Abstract: F01.00020 : Asteroseismoloy of the White Dwarf G29-38
Abstract
Presenter:
Steven Z Savery
(University of Delaware)
Authors:
Steven Z Savery
(University of Delaware)
Judith L Provencal
(University of Delaware)
White dwarfs are the last stage in life for the majority of main sequence stars. They are the cores of stars leftover after their outer layers have been blown off during the last throes of life as a red giant. White dwarfs are multi-periodic pulsators which makes them great targets for asteroseismology. Asteroseismology allows us to use the pulsations to place limits on certain aspects of the star's make-up, such as mass and internal composition. The star that I have been studying is G29-38, a variable DA white dwarf. G29-38 is extremely interesting as it was one of the first variable white dwarfs known to have a disk, which was discovered due to its high emissions in the infrared. The goal of my research is to determine the pulsation characteristics of G29-38 through examining ground and space based optical observations of the star. The data included in this project spans nearly fifty years, from 1975 to 2022. I used the python Pyriod package to create periodograms of each observing run, with these runs spanning several days to weeks. This data was used to find the frequencies of pulsation above the amplitude noise level. Over the full span of the observations, I have identified 792 frequencies in the datasets. Of these, 242 are confirmed to be combinations, with the remaining 550 being parent frequencies. I have also searched for multiplets as their difference in frequency is believed to be tied directly to the rotation rate of the white dwarf. The years of observations of G29-38 have highlighted the star's frequency and amplitude variability. For example, over just one month in 1985, the star's largest amplitude shifted nearly 400 microHertz. The next step for this work is to determine a mean period spacing from the list of parent frequencies. The mean period spacing diagnostic tool for determining the mass of the star. I will also examine the frequency multiplets seen throughout the data in an effort to determine the star's rotation period.