A theoretical framework for BL Her stars -- II. New period-luminosity relations in the Gaia passbands

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Main Authors: Das, Susmita, Molnár, László, Kanbur, Shashi M., Joyce, Meridith, Bhardwaj, Anupam, Singh, Harinder P., Marconi, Marcella, Ripepi, Vincenzo, Smolec, Radoslaw
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Published: 2024
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author Das, Susmita
Molnár, László
Kanbur, Shashi M.
Joyce, Meridith
Bhardwaj, Anupam
Singh, Harinder P.
Marconi, Marcella
Ripepi, Vincenzo
Smolec, Radoslaw
author_facet Das, Susmita
Molnár, László
Kanbur, Shashi M.
Joyce, Meridith
Bhardwaj, Anupam
Singh, Harinder P.
Marconi, Marcella
Ripepi, Vincenzo
Smolec, Radoslaw
contents We present new theoretical period-luminosity (PL) and period-Wesenheit (PW) relations for a fine grid of convective BL Her, the shortest period T2Cs, models computed using MESA-RSP and compare our results with the empirical relations from Gaia DR3. We use the state-of-the-art 1D non-linear radial stellar pulsation tool MESA-RSP to compute models of BL Her stars over a wide range of input parameters - metallicity (-2.0 dex $\leq$ [Fe/H] $\leq$ 0.0 dex), stellar mass (0.5M$_{\odot}$-0.8M$_{\odot}$), stellar luminosity (50L$_{\odot}$-300L$_{\odot}$) and effective temperature (full extent of the instability strip; in steps of 50K). The BL Her stars in the All Sky region exhibit statistically different PL slopes compared to the theoretical PL slopes computed using the four sets of convection parameters. We find the empirical PL and PW slopes from BL Her stars in the Magellanic Clouds to be statistically consistent with the theoretical relations computed using the different convection parameter sets in the Gaia passbands. There is negligible effect of metallicity on the PL relations in the individual Gaia passbands. However, there exists a small but significant negative coefficient of metallicity in the PWZ relations for the BL Her models using the four sets of convection parameters. This could be attributed to the increased sensitivity of bolometric corrections to metallicities at wavelengths shorter than the V band. Our BL Her models also suggest a dependence of the mass-luminosity relation on metallicity. We found the observed Fourier parameter space to be covered well by our models. Higher mass models (> 0.6M$_{\odot}$) may be needed to reliably model the observed light curves of BL Her stars in the All Sky region. We also found the theoretical light curve structures (especially the Fourier amplitude parameters) to be affected by the choice of convection parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11869
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A theoretical framework for BL Her stars -- II. New period-luminosity relations in the Gaia passbands
Das, Susmita
Molnár, László
Kanbur, Shashi M.
Joyce, Meridith
Bhardwaj, Anupam
Singh, Harinder P.
Marconi, Marcella
Ripepi, Vincenzo
Smolec, Radoslaw
Solar and Stellar Astrophysics
We present new theoretical period-luminosity (PL) and period-Wesenheit (PW) relations for a fine grid of convective BL Her, the shortest period T2Cs, models computed using MESA-RSP and compare our results with the empirical relations from Gaia DR3. We use the state-of-the-art 1D non-linear radial stellar pulsation tool MESA-RSP to compute models of BL Her stars over a wide range of input parameters - metallicity (-2.0 dex $\leq$ [Fe/H] $\leq$ 0.0 dex), stellar mass (0.5M$_{\odot}$-0.8M$_{\odot}$), stellar luminosity (50L$_{\odot}$-300L$_{\odot}$) and effective temperature (full extent of the instability strip; in steps of 50K). The BL Her stars in the All Sky region exhibit statistically different PL slopes compared to the theoretical PL slopes computed using the four sets of convection parameters. We find the empirical PL and PW slopes from BL Her stars in the Magellanic Clouds to be statistically consistent with the theoretical relations computed using the different convection parameter sets in the Gaia passbands. There is negligible effect of metallicity on the PL relations in the individual Gaia passbands. However, there exists a small but significant negative coefficient of metallicity in the PWZ relations for the BL Her models using the four sets of convection parameters. This could be attributed to the increased sensitivity of bolometric corrections to metallicities at wavelengths shorter than the V band. Our BL Her models also suggest a dependence of the mass-luminosity relation on metallicity. We found the observed Fourier parameter space to be covered well by our models. Higher mass models (> 0.6M$_{\odot}$) may be needed to reliably model the observed light curves of BL Her stars in the All Sky region. We also found the theoretical light curve structures (especially the Fourier amplitude parameters) to be affected by the choice of convection parameters.
title A theoretical framework for BL Her stars -- II. New period-luminosity relations in the Gaia passbands
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2401.11869