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arXiv · 2411.19741

A New Look at Disk Winds and External Photoevaporation in the $\sigma$-Orionis Cluster

K. Maucó·C. F. Manara·A. Bayo·J. Hernández·J. Campbell-White·N. Calvet·G. Ballabio·M. L. Aru·J. M. Alcalá·M. Ansdell·C. Briceño·S. Facchini·T. J. Haworth·M. McClure·J. P. Williams
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Abstract

Disk winds play a crucial role in the evolution of protoplanetary disks. Typical conditions for star and planet formation are in regions with intermediate or strong UV radiation fields produced by massive stars. The $\sigma$-Orionis cluster is the ideal site to study disk winds under these conditions; its outer parts can be used to study disk evolution, while its innermost regions to study the effect of external irradiation. For this, we analyze the $\rm [OI]\,\lambda$6300, $\rm [NII]\,\lambda$6583, and $\rm [SII]\,\lambda$6731,$\lambda$6716 lines using high-resolution MIKE spectra of 27 classical T Tauri stars and complemented by intermediate-resolution X-shooter data. We decompose the line profiles into multiple Gaussian components. We calculated luminosities, line ratios, and kinematic properties of these components. We found that the $\rm [OI]\,\lambda$6300 line luminosity and kinematic properties are similar to those found in low-mass star-forming regions (SFRs). The frequency of single-component $\rm [OI]\,\lambda$6300 line profiles reflects the expected evolutionary stage given the intermediate age of $\sigma$-Orionis. This points to internal processes contributing to the line emission. However, the highly irradiated disks do not follow the accretion - [OI] luminosity relation found in low-mass SFRs, and all exhibit single-component line profiles. Line ratios of highly ionized species of [NII] and [SII] show higher ratios than typical values found in low-mass SFRs. The innermost regions of $\sigma$-Orionis are clearly affected by external irradiation, evidenced by the lack of correlation in the accretion - [OI] luminosity relation. The broad line widths of close-in sources, however, indicate a contribution from internal processes, such as magnetohydrodynamical winds and/or internal photoevaporation. This suggests a coevolution of internal and external winds in $\sigma$-Orionis.

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K. Maucó, C. F. Manara, A. Bayo, J. Hernández, J. Campbell-White, N. Calvet, G. Ballabio, M. L. Aru, J. M. Alcalá, M. Ansdell, C. Briceño, S. Facchini, T. J. Haworth, M. McClure, J. P. Williams. 2024-11-29. A New Look at Disk Winds and External Photoevaporation in the $\sigma$-Orionis Cluster. https://doi.org/10.1051/0004-6361%2F202452386

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