We propose for the protosolar deuterium abundance: This result is based on observed values of in the solar wind and of on Jupiter; it takes into account the microscopic diffusion of elements in solar modeling. Systematic errors could occurs: i) although not yet detected, a fractionation between 3 He and 4 He could occur between the surface and the solar wind, resulting in a small decrease of the inferred , ii) microscopic diffusion coefficients could be revised, affecting the calculation of . The new protosolar value is consistent with the lower range of the preliminary determination of in Jupiter obtained by the Galileo mass spectrometer. The difference between our value and the present ISM value of Linsky et al. (1993) is compatible with some models of the chemical evolution of the Galaxy. Our result does not significantly changes the sum + , from its previous estimate of by G93. In fact, using our value , this author would have found .
© European Southern Observatory (ESO) 1997
Online publication: June 5, 1998