The role of external FUV irradiation in the survival of astrophysical
  ices in Elias 29
  The survival of astrophysical ices in the star-forming regions depends on the
suitability of temperature, density and radiation conditions. In this paper,
the role of Interstellar Radiation Field (ISRF) on ices in Elias 29 is
addressed. This object is the most luminous protostar in $\rho$ Oph E molecular
cloud, and is surrounded by many Young Stellar Objects distant only a few
arcminutes. In addition, other two brightness BV stars (S1 and HD 147889)
enhance the external irradiation in Elias 29. This study was carried out by
using the Monte Carlo radiative transfer code RADMC-3D assuming an internal and
external irradiation. As result, we found that HD 147889 dominates the ISRF,
instead of the closest protostars, and contributes to enhance the external
irradiation in 44 times the standard value. Furthermore, remarkable effects are
observed in FIR spectrum, as well as in near-IR image. Additionally, the
snowline positions of volatile compounds, such as CO, O$_2$, N$_2$ and CH$_4$
are redefined to a toroidal-shaped morphology in the envelope, with low FUV
flux (10$^{-7}$ ergs cm$^{-2}$ s$^{-1}$). In such scenario, the formation of
complex molecules as result of hydrogenation or oxygenation of volatile species
are expected to be severely affected.
