Speaker
Description
Deuterium (D) was primarily produced during Big Bang Nucleosynthesis, with a primordial abundance of [D/H] = (2.58 ± 0.13) × 10⁻⁵ (Cyburt et al. 2016). Deuterium is easily destroyed in stellar interiors through nuclear fusion making its detection in stellar atmospheres unlikely unless external processes, such as planetary engulfment, temporarily enhance surface abundances. A-type stars, with radiative envelopes, provide a favourable environment for the survival of accreted deuterium. In this study, we explore the detectability of deuterium in A-type stars, which possess radiative envelopes that can delay the mixing and destruction of accreted material. We generated synthetic spectra for stars with effective temperatures between 7500 and 12500 K and a surface gravity of log g = 4.0 using the ZEEMAN spectrum synthesis code and a grid of ATLAS9 model atmospheres. The linelist was modified by manually inserting the deuterium lines, focusing on the optical wavelength region. We applied a Markov Chain Monte Carlo (MCMC) analysis to estimate upper limits for deuterium detection across varying signal-to-noise ratios (SNRs) and temperatures. Our results show that the Hα region provides a significantly more sensitive diagnostic of deuterium than Hβ. We provide upper limits on detectable deuterium abundances as a function of SNR.