On the organic refractory component of cometary dust

被引:66
作者
Fomenkova, MN [1 ]
机构
[1] Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA
关键词
D O I
10.1023/A:1005237828783
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Cometary nuclei consist of ices intermixed with dust grains and are thought to be the least modified solar system bodies remaining from the time of planetary formation. Flyby missions to Comet P/Halley in 1986 showed that cometary dust is extremely rich in organics (similar to 50% by mass). However, this proportion appears to be variable among different comets. In comparison with the CI-chondritic abundances, the volatile elements H, C, and N are enriched in cometary dust indicating that cometary solid material is more primitive than CI-chondrites. Relative to dust in dense molecular clouds, bulk cometary dust preserves the abundances of C and N, but exhibits depletions in O and H. In most cases, the carbonaceous component of cometary particles can be characterized as a multicomponent mixture of carbon phases and organic compounds. Cluster analysis identified a few basic types of compounds, such as elemental carbon, hydrocarbons, polymers of carbon suboxide and of cyanopolyynes. In smaller amounts, polymers of formaldehyde, of hydrogen cyanide and various unsaturated nitriles also are present. These compositionally simple types, probably, are essential "building blocks", which in various combinations give rise to the variety of involatile cometary organics.
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页码:109 / 114
页数:6
相关论文
共 22 条
[1]   CYANOGEN JETS IN COMET HALLEY [J].
AHEARN, MF ;
HOBAN, S ;
BIRCH, PV ;
BOWERS, C ;
MARTIN, R ;
KLINGLESMITH, DA .
NATURE, 1986, 324 (6098) :649-651
[2]   DIAMOND IN PERSPECTIVE - A REVIEW OF MECHANICAL-PROPERTIES OF NATURAL DIAMOND [J].
BROOKES, CA ;
BROOKES, EJ .
DIAMOND AND RELATED MATERIALS, 1991, 1 (01) :13-17
[3]   THE HELIOCENTRIC EVOLUTION OF COMETARY INFRARED-SPECTRA - RESULTS FROM AN ORGANIC GRAIN MODEL [J].
CHYBA, CF ;
SAGAN, C ;
MUMMA, MJ .
ICARUS, 1989, 79 (02) :362-381
[4]  
CRONIN JR, 1993, NATO ADV SCI INST SE, V416, P209
[5]   SYSTEMATIC OBSERVATIONS OF METHANOL AND OTHER ORGANICS IN COMET P/SWIFT-TUTTLE - DISCOVERY OF NEW SPECTRAL STRUCTURE AT 3.42 MU-M [J].
DISANTI, MA ;
MUMMA, MJ ;
GEBALLE, TR ;
DAVIES, JK .
ICARUS, 1995, 116 (01) :1-17
[6]  
EBERHARDT P, 1987, ASTRON ASTROPHYS, V187, P481
[7]  
Fomenkova M, 1997, METEORIT PLANET SCI, V32, pA44
[8]  
FOMENKOVA M, 1991, LPSC, V22, P397
[9]   COMPOSITIONAL TRENDS IN ROCK-FORMING ELEMENTS OF COMET HALLEY DUST [J].
FOMENKOVA, MN ;
KERRIDGE, JF ;
MARTI, K ;
MCFADDEN, LA .
SCIENCE, 1992, 258 (5080) :266-269
[10]   CARBONACEOUS COMPONENTS IN THE COMET HALLEY DUST [J].
FOMENKOVA, MN ;
CHANG, S ;
MUKHIN, LM .
GEOCHIMICA ET COSMOCHIMICA ACTA, 1994, 58 (20) :4503-4512