OGLE-BLAP-009 -- A Case Study for the Properties and Evolution of Blue Large-Amplitude Pulsators

Blue large-amplitude pulsators (BLAPs) make up a rare class of hot pulsating stars with effective temperatures of \(\approx\)30,000 K and surface gravities of 4.0 - 5.0 dex (cgs). The evolutionary origin and current status of BLAPs is not well understood, largely based on a lack of spectroscopic obs...

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Bibliographic Details
Published inarXiv.org
Main Authors Bradshaw, Corey W, Dorsch, Matti, Kupfer, Thomas, Barlow, Brad N, Heber, Uli, Bauer, Evan B, Bildsten, Lars, Jan van Roestel
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 11.12.2023
Subjects
Amplitudes
Atmospheric models
Consistency
Constraint modelling
Gravitational lenses
Luminosity
Parallax
Pulsation
Spectral energy distribution
Spectroscopy
Spectrum analysis
White dwarf stars
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Summary:Blue large-amplitude pulsators (BLAPs) make up a rare class of hot pulsating stars with effective temperatures of \(\approx\)30,000 K and surface gravities of 4.0 - 5.0 dex (cgs). The evolutionary origin and current status of BLAPs is not well understood, largely based on a lack of spectroscopic observations and no available mass constraints. However, several theoretical models have been proposed that reproduce their observed properties, including studies that identify them as pulsating helium-core pre-white dwarfs (He-core pre-WDs). We present here follow-up high-speed photometry and phase-resolved spectroscopy of one of the original 14 BLAPs, OGLE-BLAP-009, discovered during the Optical Gravitational Lensing Experiment. We aim to explore its pulsation characteristics and determine stellar properties such as mass and radius in order to test the consistency of these results with He-core pre-WD models. Using the mean atmospheric parameters found using spectroscopy, we fit a spectral energy distribution to obtain a preliminary estimate of the radius, luminosity and mass by making use of the Gaia parallax. We then compare the consistency of these results to He-core pre-WD models generated using MESA, with predicted pulsation periods implemented using GYRE. We find that our mass constraints are in agreement with a low-mass He-core pre-WD of \(\approx\)0.30 M\(_{\odot}\).
ISSN:2331-8422