(Un)true deuterium abundance in the Galactic disk

Deuterium has a special place in cosmology, nuclear astrophysics, and galactic chemical evolution, because of its unique property that it is only created in the big bang nucleosynthesis while all other processes result in its net destruction. For tins reason, among other things, deuterium abundance measurements in the interstellar medium (ISM) allow us to determine the fraction of interstellar gas that lets been cycled through stars. and set constraints and lea, it about different Galactic chemical evolution (GCE) models However recent indications that, deuterium might be preferentially depleted onto dust grams complicate out understanding about, the meaning of measured ISM deuterium abundances For this reason, recent, estimates by Lmsky et al. (2006) have yielded a lower bound Id to the "time", undepleted: ISM deuterium abundance that is very close to the primordial abundance: indicating a small deuterium astration factor contrary to the demands of many GCE models To avoid any prejudice about. determine mum dust, depletion along different lines of sight, that, are used to determine the "time" I) abundance, we propose a model-independent statistical Bayesian method to address this issue and determine in a model-independent manner the undepleted ISM I) abundance We find the best, estimate for the gas-phase ISM deuterium abundance to be (D/H)Ism >= (2 0 +/- 0 1) x 10(-5) Presented me the results of Prodanovic et at (2009)