An experimental study of the sublimation of water ice and the release of trapped gases

Thermally induced mixing of water dominated interstellar ices

“…[22][23][24] Hence to facilitate accurate modelling of ISM processes, a detailed characterization of the adsorption and desorption of astrophysically relevant molecules from H 2 O covered surfaces is essential. Despite considerable attention in the literature given to the thermal desorption of simple volatiles detected in H 2 O-rich ices, [25][26][27][28][29][30][31][32][33] the desorption of more complex saturated molecules, such as C 2 H 5 OH, has yet to be explored. We have therefore used reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD) to investigate the adsorption and desorption of C 2 H 5 OH from various thicknesses of amorphous solid water (ASW) grown on an underlying highly oriented pyrolytic graphite (HOPG) surface at 98 K. The exact composition of interstellar dust grains is still not accurately known and depends on the astrophysical environment.…”

“…36,37 The interaction between H 2 O ice films and astrophysically relevant gas-phase molecules, and the subsequent annealing of these model interstellar ices, has received considerable attention in the literature. [25][26][27][28][29][30][31][32][33] Such processes are of particular importance to the ISM with regards to elucidating star-formation, in addition to determining the ice composition and thermal ageing of astrophysical bodies and out-gassing kinetics. 20 Several laboratory studies have demonstrated that the thermal desorption behaviour of molecules deposited on the surface of a H 2 O film, or co-deposited as a mixture, are controlled by the morphology and desorption properties of the H 2 O.…”

“…20 Several laboratory studies have demonstrated that the thermal desorption behaviour of molecules deposited on the surface of a H 2 O film, or co-deposited as a mixture, are controlled by the morphology and desorption properties of the H 2 O. [25][26][27][28][29][30][31][32] H 2 O ice is known to exist in a number of different phases, the physical properties of which depend on experimental factors including deposition temperature, deposition rate and the angular distribution of the impinging H 2 O flux. [38][39][40][41] Deposition temperatures below B130 K lead to the formation of ASW and hence this is thought to be the dominant phase observed in the ISM.…”

Survival of Amorphous Water Ice on Centaurs

“…Amorphous water ice also has the ability to trap large amounts of volatiles that can be expelled upon crystallization (Bar-Nun et al 1985;Laufer et al 1987;Hudson & Donn 1991;Jenniskens & Blake 1994;Notesco & Bar-Nun 1996;Bar-Nun & Owen 1998;Notesco et al 2003). The phase transition is an exothermic and irreversible process, which could be the source of activity in the giant planet regions, where the equilibrium temperature is too low for water ice to sublimate.…”

Thermal modeling of the active Centaur P/2004 A1 (LONEOS)

“…The physical properties of amorphous ice and its thermal behavior are known only from laboratory experiments (Bar-Nun & Owen 1998;Bar-Nun et al 1985;Bar-Nun et al 1988;Hudson & Donn 1991;Jenniskens & Blake 1994;Jenniskens et al 1998). …”