The radial structure of protostellar accretion disks: influence of jets

Laboratoire d'Astrophysique de Grenoble, Université Joseph Fourier, CNRS UMR5571, BP 53, 38041 Grenoble Cedex 9, France e-mail: ccombet@obs.ujf-grenoble.fr

Received: 25 September 2007
Accepted: 29 November 2007

Abstract

Context.The radial structure of accretion disks is a fundamental issue regarding star and planet formation. Many theoretical studies, focussing on different aspects such as e.g. disk emissivity or ionisation, have been conducted in the context of the standard accretion disk (SAD) model, where no jet is present.

Aims.We wish to calculate the structure of young stellar object (YSO) accretion disks in an approach that takes into account the presence of the protostellar jets. The radial structure of these jet emitting disks (JED) should then be compared to that of SADs.

Methods.The analytical treatment used in this work is similar to standard modelling of accretion disks but uses the parameter space of magnetised accretion-ejection structures that include the jet torque on the underlying disk. In this framework, the analytical expressions of key quantities are derived, such as mid-plane temperatures, surface densities or disk aspect ratios.

Results.We find that JEDs present a structure different from the SADs, which can be observationally tested. The implications on planet formation in the inner regions of accretion disks are briefly discussed. We also supply sets of analytical formulae, valid in different opacity regimes, for the disk quantities. These expressions can be readily used for any work where the disk structure is needed as an input for the model.