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Full Record Details
Persistent URL
http://purl.org/net/epubs/work/36463809
Record Status
Checked
Record Id
36463809
Title
Micrometer-sized Water Ice Particles for Planetary Science Experiments: Influence of Surface Structure on Collisional Properties
Contributors
Dr S Gärtner (Pr.Au.)
,
Dr B Gundlach
,
Dr TF Headen (STFC Rutherford Appleton Lab.)
,
J Ratte
,
J Oesert
,
Prof Dr SN Gorb
,
Dr TGA Youngs (STFC Rutherford Appleton Lab.)
,
Dr DT Bowron (STFC Rutherford Appleton Lab.)
,
Prof Dr J Blum
,
Dr HJ Fraser
Abstract
Models and observations suggest that ice-particle aggregation at and beyond the snowline dominates the earliest stages of planet formation, which therefore is subject to many laboratory studies. However, the pressure–temperature gradients in protoplanetary disks mean that the ices are constantly processed, undergoing phase changes between different solid phases and the gas phase. Open questions remain as to whether the properties of the icy particles themselves dictate collision outcomes and therefore how effectively collision experiments reproduce conditions in protoplanetary environments. Previous experiments often yielded apparently contradictory results on collision outcomes, only agreeing in a temperature dependence setting in above ≈210 K. By exploiting the unique capabilities of the NIMROD neutron scattering instrument, we characterized the bulk and surface structure of icy particles used in collision experiments, and studied how these structures alter as a function of temperature at a constant pressure of around 30 mbar. Our icy grains, formed under liquid nitrogen, undergo changes in the crystalline ice-phase, sublimation, sintering and surface pre-melting as they are heated from 103 to 247 K. An increase in the thickness of the diffuse surface layer from ≈10 to ≈30 Å (≈2.5 to 12 bilayers) proves increased molecular mobility at temperatures above ≈210 K. Because none of the other changes tie-in with the temperature trends in collisional outcomes, we conclude that the surface pre-melting phenomenon plays a key role in collision experiments at these temperatures. Consequently, the pressure–temperature environment, may have a larger influence on collision outcomes than previously thought.
Organisation
ISIS
,
ISIS-NIMROD
,
STFC
Keywords
planets and satellites: formation
,
laboratory astrophysics
,
accretion disks
,
neutron scattering
,
laboratory astrochemisty
,
solid state
,
water ice
,
characterisation
Funding Information
STFC
(ST/M007790/1);
STFC
(ST/M003051/1);
STFC
(ST/N006488/1);
STFC
(ST/N005775/1);
STFC
(ST/L000776/1);
Royal Society
, International Exchange Award (IE/14/3);
COST
, CM1401 (STSM—100615-061929);
DLR
(50WM1536)
Related Research Object(s):
Licence Information:
Language
English (EN)
Type
Details
URI(s)
Local file(s)
Year
Journal Article
Astrophys J
848, no. 2 (2017): 96.
doi:10.3847/1538-4357/aa8c7f
2017
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