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Low Extreme-ultraviolet Luminosities Impinging on Protoplanetary Disks

Pascucci, I. and Ricci, L. and Gorti, U. and Hollenbach, D. and Hendler, N. P. and Brooks, K. J. and Contreras, Y. (2014) Low Extreme-ultraviolet Luminosities Impinging on Protoplanetary Disks. Astrophysical Journal, 795 (1). Art. No. 1. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20141201-085720292

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Abstract

The amount of high-energy stellar radiation reaching the surface of protoplanetary disks is essential to determine their chemistry and physical evolution. Here, we use millimetric and centimetric radio data to constrain the extreme-ultraviolet (EUV) luminosity impinging on 14 disks around young (~2-10 Myr) sun-like stars. For each object we identify the long-wavelength emission in excess to the dust thermal emission, attribute that to free-free disk emission, and thereby compute an upper limit to the EUV reaching the disk. We find upper limits lower than 10^(42) photons s^(–1) for all sources without jets and lower than 5 × 10^(40) photons s^(–1) for the three older sources in our sample. These latter values are low for EUV-driven photoevaporation alone to clear out protoplanetary material in the timescale inferred by observations. In addition, our EUV upper limits are too low to reproduce the [Ne II] 12.81 μm luminosities from three disks with slow [Ne II]-detected winds. This indicates that the [Ne II] line in these sources primarily traces a mostly neutral wind where Ne is ionized by 1 keV X-ray photons, implying higher photoevaporative mass loss rates than those predicted by EUV-driven models alone. In summary, our results suggest that high-energy stellar photons other than EUV may dominate the dispersal of protoplanetary disks around sun-like stars.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://iopscience.iop.org/0004-637X/795/1/1/PublisherArticle
http://dx.doi.org/10.1088/0004-637X/795/1/1DOIArticle
ORCID:
AuthorORCID
Pascucci, I.0000-0001-7962-1683
Hendler, N. P.0000-0002-3164-0428
Additional Information:© 2014 American Astronomical Society. Received 2014 June 27; accepted 2014 August 21; published 2014 October 8. The authors thank the anonymous referee for a prompt and useful report. I.P. thanks Cathie Clarke for stimulating discussion. I.P., U.G., and D.H. acknowledge support from an NSF Astronomy & Astrophysics Research Grant (ID: 1312962). Facility: ATCA
Funders:
Funding AgencyGrant Number
NSF1312962
Subject Keywords:protoplanetary disks; radio continuum: stars; stars: pre-main sequence
Issue or Number:1
Record Number:CaltechAUTHORS:20141201-085720292
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141201-085720292
Official Citation:Low Extreme-ultraviolet Luminosities Impinging on Protoplanetary Disks I. Pascucci et al. 2014 ApJ 795 1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52198
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:01 Dec 2014 18:10
Last Modified:09 Mar 2020 13:19

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