Searcharxiv⌕ Search

arXiv subjects

Momin Y. Khan

Publications and source records attributed to Momin Y. Khan.

2 recordsLinked to original sources

Analysis of DQZ White Dwarf Evolution through Procyon

Procyon is a great system to probe stellar evolution of non-interacting binaries. We present an extensive grid of MESA (Modules for Experiments in Stellar Astrophysics) evolutionary tracks to constrain the evolution of Procyon A and B. We systematically vary the initial parameters of our grid anchored by precise dynamical masses and spectroscopic determinations of effective temperature (T$_{eff}$) and luminosity ($L$) to match the stars' positions on the H-R Diagram. Our goal is two-fold: (i) to quantify how the inferred system age and the progenitor mass of Procyon B depend on metallicity ($Z$), mixing length ($α$), and core overshoot ($β$), and (ii) to determine the best fitting model of Procyon B within a model-based initial-to-final mass relationship (IMFR) for hydrogen-deficient white dwarfs. Our best-fit models reproduce the observed properties for both components, yielding $M_\mathrm{A}=1.487 \pm 0.095$ M$_{\odot}$, $M_\mathrm{B}=0.592\pm 0.082$ M$_{\odot}$, a system age of $2.23 \pm 0.90$ Gyr, and a white dwarf cooling age of $1.20\pm0.49$ Gyr for Procyon B, consistent with independent determinations. Our results point to higher core overshoot than the standard adopted range, with the best fits ranging from $β=0.5-1.0$. From our model grid, we map Procyon B to the initial-to-final mass relationship for H-deficient white dwarfs in the $1.9\!-\!2.6$ M$_{\odot}$ progenitor range. Additionally, we implement the accretion of heavy metals onto the surface of the WD and fit our isotopic abundances to spectroscopic observations. We outline the physics used in our analysis.

astro-ph.SR↗

Astrophysical Properties of the Sirius Binary System Modeled with MESA

Sirius is the brightest star in the night sky and, despite its proximity, this binary system still imposes intriguing questions about its current characteristics and past evolution. Bond et. al. (arXiv:1703.10625) published decades of astrometric measurements of the Sirius system, determining the dynamical masses for Sirius A and B, and the orbital period. We have used these determinations, combined with photometric determinations for luminosity and spectroscopic determinations of effective temperature ($T_{eff}$) and metallicity, to model the evolution of the Sirius system using MESA (Modules for Experiments in Stellar Astrophysics). We have constructed a model grid calculated especially for this system and were able to obtain, for Sirius B, a progenitor mass of $6.0 \pm 0.6 M_{\odot}$, yielding a white dwarf mass of $1.015 \pm 0.189 M_{\odot}$. Our best determination for age of the system is $203.6 \pm 45$ Myr with a metallicity of 0.0124. We have compared our best fit models with the ones computed using TYCHO, YREC, and PARSEC, establishing external uncertainties. Our results are consistent with the observations and support a non-interacting past.

astro-ph.SR↗