Dust cleansing of star-forming gas

I. Has radiation from bright stars affected the chemical composition of the Sun and M 67?

Department of Physics and Astronomy, Uppsala University, Sweden
e-mail: bengt.gustafsson@physics.uu.se
Nordic Institute for Theoretical Physics (NORDITA), Stockholm, Sweden

Received: 24 November 2017
Accepted: 3 April 2018

Abstract

Aims. We explore the possibility that solar chemical composition, as well as the similar composition of the rich open cluster M 67, have been affected by dust cleansing of the presolar or precluster cloud due to the radiative forces from bright early-type stars in its neighbourhood.

Methods. We estimate possible cleansing effects using semi-analytical methods, which are essentially based on momentum conservation.

Results. Our calculations indicate that the amounts of cleansed neutral gas are limited to a relatively thin shell surrounding the H II region around the early-type stars.

Conclusions. It seems possible that the proposed mechanism acting in individual giant molecular clouds may produce significant abundance effects for masses corresponding to single stars or small groups of stars. The effects of cleansing are, however, severely constrained by the thinness of the cleansed shell of gas and by turbulence in the cloud. This is why the mechanism can hardly be important in cleansing masses corresponding to rich clusters, such as the mass of the original M 67.