A Herschel view of protoplanetary disks in the $\sigma$ Ori cluster

Abstract

We present new Herschel PACS observations of 32 T Tauri stars in the young ($\sim$3 Myr) $\sigma$ Ori cluster. Most of our objects are K & M stars with large excesses at 24 $\mu$m. We used irradiated accretion disk models of D'Alessio et al. (2006) to compare their spectral energy distributions with our observational data. We arrive at the following six conclusions. (i) The observed disks are consistent with irradiated accretion disks systems. (ii) Most of our objects (60%) can be explained by significant dust depletion from the upper disk layers. (iii) Similarly, 61% of our objects can be modeled with large disk sizes (${\mathrm{R}}_{\mathrm{d}}\ge$ 100 AU). (iv) The masses of our disks range between 0.03 to 39 ${\mathrm{M}}_{\mathrm{Jup}}$, where 35% of our objects have disk masses lower than 1 Jupiter. Although these are lower limits, high mass ($>$ 0.05 M${}_{\odot }$) disks, which are present e.g, in Taurus, are missing. (v) By assuming a uniform distribution of objects around the brightest stars at the center of the cluster, we found that 80% of our disks are exposed to external FUV radiation of $300\le G_0\le 1000$, which can be strong enough to photoevaporate the outer edges of the closer disks. (vi) Within 0.6 pc from $\sigma$ Ori we found forbidden emission lines of [NII] in the spectrum of one of our large disk (SO662), but no emission in any of our small ones. This suggests that this object may be an example of a photoevaporating disk.

Accepted by the Astrophysical Journal. 37 pages, 20 figures. Section 6 presents estimations of disks masses and radii and evidence of external photoevaporation

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Cited by in corpus (16)

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• Bridging the gap between protoplanetary and debris disks: separate evolution of millimeter and micrometer-sized dust
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• Towards a comprehensive view of accretion, inner disks, and extinction in classical T Tauri stars: an ODYSSEUS study of the Orion OB1b association
• Proplyds in the Flame Nebula NGC 2024
• Ionization: a possible explanation for the difference of mean disk sizes in star-forming regions
• The Evolution Of The Inner Regions of Protoplanetary Disks
• Testing external photoevaporation in the $\sigma$-Orionis cluster with spectroscopy and disk mass measurements
• Determining Dust Properties in Protoplanetary Disks: SED-derived Masses and Settling With ALMA
• Testing viscous disc theory using the balance between stellar accretion and external photoevaporation of protoplanetary discs
• PENELLOPE IV. A comparison between optical forbidden lines and ${\mathrm{H}}_2$ UV lines in the Orion OB1b and $\sigma$-Ori associations
• The Radial Distribution and Excitation of H2 around Young Stars in the HST-ULLYSES Survey
• Lyman-alpha Scattering Models Trace Accretion and Outflow Kinematics in T Tauri Systems
• A New Look at Disk Winds and External Photoevaporation in the $\sigma$-Orionis Cluster
• Understanding the angular momentum evolution of T Tauri and Herbig Ae/Be stars
• An upper limit for the growth of inner planets?