A New Probe of the Planet-forming Region in T Tauri Disks - Archive ouverte HAL Access content directly
Journal Articles The Astrophysical journal letters Year : 2004

A New Probe of the Planet-forming Region in T Tauri Disks

Abstract

We present new observations of the far-ultraviolet (FUV; 1100-2200 Å) radiation field and the near- to mid-IR (3-13.5 mum) spectral energy distribution (SED) of a sample of T Tauri stars selected on the basis of bright molecular disks (GM Aur, DM Tau, and LkCa 15). In each source we find evidence for Lyalpha-induced H2 fluorescence and an additional source of FUV continuum emission below 1700 Å. Comparison of the FUV spectra to a model of H2 excitation suggests that the strong continuum emission is due to electron impact excitation of H2. The ultimate source of this excitation is likely X-ray irradiation that creates hot photoelectrons mixed in the molecular layer. Analysis of the SED of each object finds the presence of inner disk gaps with sizes of a few AU in each of these young (~1 Myr) stellar systems. We propose that the presence of strong H2 continuum emission and inner disk clearing are related by the increased penetration power of high-energy photons in gas-rich regions with low grain opacity.
No file

Dates and versions

hal-03730879 , version 1 (20-07-2022)

Identifiers

Cite

Edwin A. Bergin, Nuria Calvet, Michael L. Sitko, Hervé Abgrall, Paola d'Alessio, et al.. A New Probe of the Planet-forming Region in T Tauri Disks. The Astrophysical journal letters, 2004, 614, pp.L133-L136. ⟨10.1086/425865⟩. ⟨hal-03730879⟩
9 View
0 Download

Altmetric

Share

Gmail Facebook X LinkedIn More