Forskning ved Københavns Universitet - Københavns Universitet


Levitation of dust at the surface of protoplanetary disks

Publikation: Bidrag til bog/antologi/rapportKonferencebidrag i proceedingsForskningfagfællebedømt

  • Gerhard Wurm
  • Henning Haack

In recent years photophoretic forces acting on dust particles have been shown to be important for optically thin parts of protoplanetary disks. The optical surface (photosphere) of protoplanetary disks is a transitional region where the thermal radiation of the disk can escape. We show here that photophoresis by the thermal radiation is sufficient to levitate dust particles at several pressure scale heights. Under certain conditions these particles can constitute the surface layer. In this case only the particles which are most susceptible to photophoresis are observed at the surface of protoplanetary disks. In general these are small particles with low thermal conductivity, probably highly porous dust aggregates. If optical properties vary strongly for given dust aggregatesthe more absorbing aggregates are lifted the highest. Overall, levitationby thermal radiation introduces a bias into the observed dust. The surface dust does not necessarily reflect the properties of dust below the surface.

TitelCosmic Dust—Near and Far
RedaktørerThomas Henning, Eberhard Grün, Jürgen Steinacker
Antal sider11
ForlagAstronomical Society of the Pacific
ISBN (Trykt)978-1-58381-708-7
ISBN (Elektronisk)978-1-58381-709-4
StatusUdgivet - 2009
BegivenhedCosmic Dust - Near and Far - Heidelberg, Tyskland
Varighed: 8 sep. 200812 sep. 2008


KonferenceCosmic Dust - Near and Far
NavnAstronomical Society of the Pacific. Conference Proceedings

ID: 174732134