Forbidden emission lines in protostellar outflows and jets with MUSE

¹ Max Planck Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
e-mail: flores@mpia.de
² Department of Physics, Texas State University, San Marcos, 601 University Dr, San Marcos, TX 78666, USA
³ Institutionen för astronomi, Stockholms universitet, AlbaNova universitetscentrum, 106 91, Stockholm, Sweden
⁴ Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF, UK
⁵ School of Physics, University College, Belfield, Dublin 4, Ireland
⁶ Fakultät für Physik, Universität Duisburg-Essen, Lotharstraße 1, 47057 Duisburg, Germany
⁷ Institut für Astronomie und Astrophysik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
⁸ Physikalisches Institut, Universität Bern, Gesellschaftsstr. 6, 3012 Bern, Switzerland
⁹ Instituto de Radioastronomía y Astrofísica(IRyA), Universidad Nacional Autónoma de México (UNAM), Mexico
¹⁰ Institute for Advanced Study, Tsinghua University, Beijing 100084, PR China

Received: 29 June 2021
Accepted: 19 December 2022

Abstract

Context. Forbidden emission lines in protoplanetary disks are a key diagnostic in studies of the evolution of the disk and the host star. They signal potential disk accretion or wind, outflow, or jet ejection processes of the material that affects the angular momentum transport of the disk as a result.

Aims. We report spatially resolved emission lines, namely, [O I] λλ6300, 6363, [N II] λλ6548, 6583, Hα, and [S II] λλ6716, 6730 that are believed to be associated with jets and magnetically driven winds in the inner disks, due to the proximity to the star, as suggested in previous works from the literature. With a resolution of 0.025 × 0.025 arcsec², we aim to derive the position angle of the outflow/jet (PA_outflow/jet) that is connected with the inner disk. We then compare it with the position angle of the dust (PA_dust) obtained from previous constraints for the outer disk. We also carry out a simple analysis of the kinematics and width of the lines and we estimate the mass-loss rate based on the [O I] λ6300 line for five T Tauri stars.

Methods. Observations were carried out with the optical integral field spectrograph of the Multi Unit Spectroscopic Explorer (MUSE), at the Very Large Telescope (VLT). The instrument spatially resolves the forbidden lines, providing a unique capability to access the spatial extension of the outflows/jets that make the estimate of the PA_outflow/jet possible from a geometrical point of view.

Results. The forbidden emission lines analyzed here have their origin at the inner parts of the protoplanetary disk. From the maximum intensity emission along the outflow/jet in DL Tau, CI Tau, DS Tau, IP Tau, and IM Lup, we were able to reliably measure the PA_outflow/jet for most of the identified lines. We found that our estimates agree with PA_dust for most of the disks. These estimates depend on the signal-to-noise level and the collimation of the outflow (jet). The outflows/jets in CIDA 9, GO Tau, and GW Lup are too compact for a PA_outflow/jet to be estimated. Based on our kinematics analysis, we confirm that DL Tau and CI Tau host a strong outflow/jet with line-of-sight velocities much greater than 100 km s⁻¹, whereas DS Tau, IP Tau, and IM Lup velocities are lower and their structures encompass low-velocity components to be more associated with winds. Our estimates for the mass-loss rate, Ṁ_loss, range between (1.1–6.5) × 10⁻⁷–10⁻⁸ M_⊙ yr⁻¹ for the disk-outflow/jet systems analyzed here.

Conclusions. The outflow/jet systems analyzed here are aligned within around 1° between the inner and outer disk. Further observations are needed to confirm a potential misalignment in IM Lup.