Complex processes in simple ices : laboratory and observational studies of gas-grain interactions during star formation

The similar or higher abundance of CH 4 with respect to H 2 O toward the low mass sources in this sample compared to what has been found previously toward high mass young stel-

In addition, the spectra of ice mixtures with higher CO 2 concentration are more a ffected by changes in temperature than those of ices with less CO 2 ; the influence of CO

Figure 5.1 – Spectra illus- trating the changes in the CO 2 stretching feature as the ice segregation proceeds in a 18 ML thick 2:1 H 2 O:CO 2 ice at 55 K (Exp. Following deposition

Using pure ice desorption energies and one di ffusion parameter for H 2 O, CO 2 and CO each, the modified three-phase model can reproduce the amount of trapped ice quantitatively in

Equations 8.2 and 8.3 describe the photodesorption rates of CO molecules from grain surfaces in molecules cm −2 s −1 due to external and cosmic ray induced UV photons,

Figure 8.12 – Total CO 2 (crosses) and CO-from-CO 2 (squares) photodesorption yield dependences on different parameters. The two measurements of 5.5 and 5.6 ML ices in a) are from

Figure 9.4 – Ice thickness (in ML) versus photon fluence (in 10 17 photons cm −2 ) for ∼10 ML D 2 O ices at di fferent temperatures, displaying the temperature dependent degree of

The more complex molecules also behave as expected following the assumption that they form from recombining radicals; all complex ice abundances initially increase be- fore