Search for DBVs with Gemini Observatory's 'Alopeke
Abstract
We are using Gemini Observatory's resident instrument 'Alopeke to search for new He atmosphere pulsating white dwarf stars (DBVs). Our goal is to explore various processes of convection and stellar neutrino production via asteroseismology using the new white dwarf pulsators. White dwarf stars are ideal laboratories for investigating both high energy physics and astrophysics, as they are very hot and dense. More than 97% of all stars evolve to white dwarfs. As white dwarfs evolve and cool, they pulsate within certain temperature ranges known as instability strips. We can therefore study the interiors of these stars through asteroseismology. One of the advantages of studying their structures is to learn the boundary conditions to late stage of stellar evolution which involves dynamical processes, especially mass loss which have large uncertainties. Studying their interior structure also gives us opportunities to test our knowledge of high energy physics not reproducible in Earth-based labs. The most numerous of the pulsating white dwarf stars are the H atmosphere pulsating white dwarf stars, the DAVs or ZZ Ceti stars. The DBVs pulsate at a higher effective temperatures than do the DAVs and there are far fewer known DBVs than DAVs. We have started a search to identify new DBVs and are particularly searching around the hot and cool ends of the instability strip to better determine the boundaries of the strip. The hottest DBVs will be useful in studying stellar neutrino production via asteroseismology. And other DBVs at various effective temperatures will help study the changes in convection as the white dwarf stars evolve through the instability strip. Here we report the project's progress and the data obtained using 'Alopeke at Gemini Observatory. 'Alopeke is a fast, low-noise, dual-channel, and dual-plate-scale imager based on the Differential Speckle Survey Instrument (DSSI). We use it in the wide-field imaging mode to allow observations of at least one reference star along with our target DBV candidate.
- Publication:
-
American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23510505N