Dust cleansing of star-forming gas

II. Did late accretion flows change the chemical composition of the solar atmosphere?

¹ Department of Physics and Astronomy, Uppsala University, Sweden
e-mail: bengt.gustafsson@physics.uu.se
² Nordic Institute for Theoretical Physics (NORDITA), Stockholm, Sweden

Received: 3 May 2018
Accepted: 31 August 2018

Abstract

Aims. The possibility that the chemical composition of the solar atmosphere has been affected by radiative dust cleansing of late and weak accretion flows by the proto-sun itself is explored.

Methods. Estimates, using semi-analytical methods and numerical simulations of the motion of dust grains in a collapsing non-magnetic and non-rotating gas sphere with a central light source are made in order to model possible dust-cleansing effects.

Results. Our calculations indicate that the amount of cleansed material may well be consistent with the abundance differences observed for the Sun when compared with solar-like stars and with the relations found between these differences and the condensation temperature of the element.

Conclusions. It seems quite possible that the proposed mechanism produced the significant abundance effects observed for the Sun, provided that late and relatively weak accretion did occur. The effects of cleansing may, however, be affected by outflows from the Sun, the existence and dynamics of magnetic fields and of the accretion disk, and the possible presence and location of the early Sun in a rich stellar cluster.