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Title: Photophoretic strength on chondrules. 2. Experiment

Photophoretic motion can transport illuminated particles in protoplanetary disks. In a previous paper, we focused on the modeling of steady state photophoretic forces based on the compositions derived from tomography and heat transfer. Here, we present microgravity experiments which deviate significantly from the steady state calculations of the first paper. The experiments on average show a significantly smaller force than predicted with a large variation in absolute photophoretic force and in the direction of motion with respect to the illumination. Time-dependent modeling of photophoretic forces for heat-up and rotation shows that the variations in strength and direction observed can be well explained by the particle reorientation in the limited experiment time of a drop tower experiment. In protoplanetary disks, random rotation subsides due to gas friction on short timescales and the results of our earlier paper hold. Rotation has a significant influence in short duration laboratory studies. Observing particle motion and rotation under the influence of photophoresis can be considered as a basic laboratory analog experiment to Yarkovsky and YORP effects.
Authors:
; ; ;  [1] ;  [2] ;  [3]
  1. Faculty of Physics, University of Duisburg-Essen, Lotharstrasse 1, D-47057 Duisburg (Germany)
  2. Department of Chemistry, Fordham University, Bronx, NY 10458 (United States)
  3. Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, D-48149 Münster (Germany)
Publication Date:
OSTI Identifier:
22365175
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; 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; COOLING TOWERS; HEAT; HEAT TRANSFER; ILLUMINANCE; PLANETARY NEBULAE; PLANETS; PROTOPLANETS; RANDOMNESS; ROTATION; SATELLITES; SIMULATION; STEADY-STATE CONDITIONS; TIME DEPENDENCE; TOMOGRAPHY; VARIATIONS