DEVELOPMENT OF A DUST MANTLE ON THE SURFACE OF AN INSOLATED ICE-DUST MIXTURE - RESULTS FROM THE KOSI-9 EXPERIMENT

被引:95
作者
GRUN, E
GEBHARD, J
BARNUN, A
BENKHOFF, J
DUREN, H
EICH, G
HISCHE, R
HUEBNER, WF
KELLER, HU
KLEES, G
KOCHAN, H
KOLZER, G
KROKER, H
KUHRT, E
LAMMERZAHL, P
LORENZ, E
MARKIEWICZ, WJ
MOHLMANN, D
OEHLER, A
SCHOLZ, J
SEIDENSTICKER, KJ
ROESSLER, K
SCHWEHM, G
STEINER, G
THIEL, K
THOMAS, H
机构
[1] TEL AVIV UNIV, DEPT GEOPHYS & PLANETARY SCI, IL-69978 TEL AVIV, ISRAEL
[2] WESTFAL WILHELMS UNIV, INST PLANETOL, D-48149 MUNSTER, GERMANY
[3] KFA JULICH, FORSCHUNGSZENTRUM, INST NUKL CHEM, D-52425 JULICH, GERMANY
[4] SW RES INST, SAN ANTONIO, TX 78228 USA
[5] MAX PLANCK INST AERON, D-37189 KATLENBURG DUHM, GERMANY
[6] UNIV COLOGNE, NUKL CHEM ABT, D-50674 COLOGNE, GERMANY
[7] INST WELTRAUMFORSCH, A-8010 GRAZ, AUSTRIA
[8] DFVLR, INST RAUMSIMULAT, COLOGNE, GERMANY
[9] DFVLR, INST WELTRAUMSENSOR, BERLIN, GERMANY
[10] DFVLR, INST OPTOELEKTR, WESSELING, GERMANY
[11] EUROPEAN SPACE TECHNOL CTR, DEPT SPACE SCI, NOORDWIJK, NETHERLANDS
关键词
D O I
10.1029/93JE01134
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Astronomical observations indicate that formation and destruction of dust mantles on cometary nuclei may be the cause for erratic and systematic variations of cometary activity. i.e. emission of dust. A laboratory experiment (KOSI-9) has been performed to study the evolution of a dust mantle on top of a sublimating ice-dust mixture in vacuum. A sample consisting of water ice with a 10% (by weight) admixture of olivine grains has been insolated in three periods at variable intensities from 200 to 1900 W/m2. Both increasing surface temperature of the sample and decreasing gas and particle emissions indicated the formation of a dust mantle during the first period. During the second insolation period after the gas flux had reached a critical value of a few 1021 water molecules m-2s-1, avalanches of mantle material occurred on the inclined sample surface, broke up the mantle locally, and opened up a fresh icy surface. Enhanced ice and dust particle emission resumed lor some time from these spots. A large number of the emitted dust particles were of a fluffy aggregate structure, i.e., they had large cross section to mass ratios compared to compact particles. During the third period the critical gas flux was not reached and no enhanced dust and ice emission was observed. A dry dust mantle of a few millimeters thickness developed during the course of the experiment. Consequences of these findings for cometary scenarios are discussed.
引用
收藏
页码:15091 / 15104
页数:14
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