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Title: Planetesimal Formation in the Warm, Inner Disk: Experiments with Tempered Dust

Abstract

It is an open question how elevated temperatures in the inner parts of protoplanetary disks influence the formation of planetesimals. We approach this problem here by studying the tensile strength of granular beds with dust samples tempered at different temperatures. We find via laboratory experiments that tempering at increasing temperatures is correlated with an increase in cohesive forces. We studied dust samples of palagonite (JSC Mars-1a) which were tempered for up to 200 hr at temperatures between 600 and 1200 K, and measured the relative tensile strengths of highly porous dust layers once the samples cooled to room temperature. Tempering increases the tensile strength from 800 K upwards. This change is accompanied by mineral transformations, the formation of iron oxide crystallites as analyzed by Mössbauer spectroscopy, changes in the number size distribution, and the morphology of the surface visible as cracks in larger grains. These results suggest a difference in the collisional evolution toward larger bodies with increasing temperature as collisional growth is fundamentally based on cohesion. While high temperatures might also increase sticking (not studied here), compositional evolution will already enhance the cohesion and the possibility of growing larger aggregates on the way toward planetesimals. This might lead tomore » a preferred in situ formation of inner planets and explain the observed presence of dense inner planetary systems.« less

Authors:
; ; ; ;  [1]
  1. Faculty of Physics, University of Duisburg-Essen, Lotharstr. 1, D-47057 Duisburg (Germany)
Publication Date:
OSTI Identifier:
22661324
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DISTRIBUTION; DUSTS; EVOLUTION; IRON; IRON OXIDES; LAYERS; MARS PLANET; MOESSBAUER EFFECT; POROUS MATERIALS; PROTOPLANETS; SATELLITES; SOLIDS; SURFACES; TENSILE PROPERTIES

Citation Formats

De Beule, Caroline, Landers, Joachim, Salamon, Soma, Wende, Heiko, and Wurm, Gerhard, E-mail: gerhard.wurm@uni-due.de. Planetesimal Formation in the Warm, Inner Disk: Experiments with Tempered Dust. United States: N. p., 2017. Web. doi:10.3847/1538-4357/837/1/59.
De Beule, Caroline, Landers, Joachim, Salamon, Soma, Wende, Heiko, & Wurm, Gerhard, E-mail: gerhard.wurm@uni-due.de. Planetesimal Formation in the Warm, Inner Disk: Experiments with Tempered Dust. United States. doi:10.3847/1538-4357/837/1/59.
De Beule, Caroline, Landers, Joachim, Salamon, Soma, Wende, Heiko, and Wurm, Gerhard, E-mail: gerhard.wurm@uni-due.de. Wed . "Planetesimal Formation in the Warm, Inner Disk: Experiments with Tempered Dust". United States. doi:10.3847/1538-4357/837/1/59.
@article{osti_22661324,
title = {Planetesimal Formation in the Warm, Inner Disk: Experiments with Tempered Dust},
author = {De Beule, Caroline and Landers, Joachim and Salamon, Soma and Wende, Heiko and Wurm, Gerhard, E-mail: gerhard.wurm@uni-due.de},
abstractNote = {It is an open question how elevated temperatures in the inner parts of protoplanetary disks influence the formation of planetesimals. We approach this problem here by studying the tensile strength of granular beds with dust samples tempered at different temperatures. We find via laboratory experiments that tempering at increasing temperatures is correlated with an increase in cohesive forces. We studied dust samples of palagonite (JSC Mars-1a) which were tempered for up to 200 hr at temperatures between 600 and 1200 K, and measured the relative tensile strengths of highly porous dust layers once the samples cooled to room temperature. Tempering increases the tensile strength from 800 K upwards. This change is accompanied by mineral transformations, the formation of iron oxide crystallites as analyzed by Mössbauer spectroscopy, changes in the number size distribution, and the morphology of the surface visible as cracks in larger grains. These results suggest a difference in the collisional evolution toward larger bodies with increasing temperature as collisional growth is fundamentally based on cohesion. While high temperatures might also increase sticking (not studied here), compositional evolution will already enhance the cohesion and the possibility of growing larger aggregates on the way toward planetesimals. This might lead to a preferred in situ formation of inner planets and explain the observed presence of dense inner planetary systems.},
doi = {10.3847/1538-4357/837/1/59},
journal = {Astrophysical Journal},
number = 1,
volume = 837,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}