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sdB Grid Viewer

sdB Grid Viewer is the tool to quickly inspect the grid of evolutionary models of sdB stars calculated for the ARDASTELLA research group.

Overview of the grid

The models were calculated using the set-up described by Ostrowski et al. (2021) , utilizing the computational resources provided by Wrocław Centre for Networking and Supercomputing. Evolutionary models were calculated using the MESA code (Paxton et al. 2011 , 2013, 2015, 2018, 2019), version 11701, and supplemented by adiabatic non-radial pulsation models calculated using the GYRE code (Townsend & Teitler 2013 , Townsend et al. 2018 , Goldstein & Townsend 2020) , version 5.2.

The models were calculated for progenitors with initial masses, Mi, in the range of 1.0 − 1.8 Ms, with a step of 0.005 Ms, and metallicities, Z, in the range of 0.005 − 0.035, with a step of 0.005. The considered envelope masses, Menv, are in the range of 0.0001 − 0.0030 Ms, with a step of 0.0001 Ms, and 0.003 − 0.010 Ms, with a step of 0.001 Ms. Central helium abundance, Yc, is in the range of 0.9 − 0.1, with a step of 0.05.

The full grid is not publicly available at the moment.

Available data

The selection of columns available in sdB Grid Viewer:

  • id - id of a model
  • m_i - initial mass of a progenitor (solar units)
  • m_env - envelope mass of an sdb model (solar units)
  • z_i - initial metallicity of a progenitor
  • y_i - initial helium abundance of a progenitor
  • m_he_core - mass of a helium core of progenitor before removal of the envelope
  • log_g - logarithm of surface gravity of a model (cgs)
  • radius - radius of a model (solar units)
  • age - total age of a model calculated from the beginning of the PMS evolution (years)
  • z_surf - surface metallicity of a model
  • y_surf - surface helium abundance of a model
  • center_he4 - exact central helium abundance of a model
  • y_c - central helium abundance of a model rounded to two decimal points
  • Teff - effective temperature of a model
  • L - luminosity of a model (solar units)

Usage

Settings

Options in the menu:

  • Select color - select a parameter shown by color. Options: z_i, m_i, m_env, center_he4.
  • Select symbols - select a parameter shown by symbols. Options: z_i, m_i, m_env, center_he4.
  • Z_i - initial metallicity of progenitors
  • M_i - initial mass of progenitors in solar units
  • M_env - envelope mass of sdB models in solar units
  • Y_c - central helium abundance of sdB models
  • Hover data - select parameters shown for data points in the hover menu
  • Target - optional parameters of a target star, which allow an error box (up to $3\sigma$) to be plotted over the grid

Available plots

There are three predefined plots available: logg vs. Teff, L vs. Teff, and R vs. Teff, and also a custom plot that can be customized to show any grid columns accessible by sdB Grid Viewer. The custom plot also allows user to reverse axes and apply to them the base-10 logarithmic or exponential function.

Limitations

  • The app does not support the small (smartphone) screens.
  • The initial start-up time might be slow, due to the limitation of the free Heroku tier.

Acknowledgements

The author was financially supported by the Polish National Science Centre grant UMO-2017/26/E/ST9/00703. The grid of models was calculated using the resources provided by Wrocław Centre for Networking and Supercomputing, grant No. 265.