Low extreme-ultraviolet luminosities impinging on protoplanetary disks

I. Pascucci, L. Ricci, U. Gorti, D. Hollenbach, N. P. Hendler, K. J. Brooks, Y. Contreras

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


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 1042 photons s-1 for all sources without jets and lower than 5 × 1040 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.

Original languageEnglish (US)
Article number1
JournalAstrophysical Journal
Issue number1
StatePublished - Nov 1 2014


  • Protoplanetary disks
  • Radio continuum: stars
  • Stars: pre-main sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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