SIMBAD references

2014ApJ...795....1P - Astrophys. J., 795, 1 (2014/November-1)

Low extreme-ultraviolet luminosities impinging on protoplanetary disks.

PASCUCCI I., RICCI L., GORTI U., HOLLENBACH D., HENDLER N.P., BROOKS K.J. and CONTRERAS Y.

Abstract (from CDS):

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 for all sources without jets and lower than 5x1040 photons/s 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.

Abstract Copyright:

Journal keyword(s): protoplanetary disks - radio continuum: stars - stars: pre-main sequence

Simbad objects: 33

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2019.12.07-09:51:01

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