Flux and composition of interstellar dust at Saturn from Cassini's Cosmic Dust Analyzer

N Altobelli; F Postberg; K Fiege; M Trieloff; H Kimura; V J Sterken; H-W Hsu; J Hillier; N Khawaja; G Moragas-Klostermeyer; J Blum; M Burton; R Srama; S Kempf; E Gruen

doi:10.1126/science.aac6397

Flux and composition of interstellar dust at Saturn from Cassini's Cosmic Dust Analyzer

Science. 2016 Apr 15;352(6283):312-8. doi: 10.1126/science.aac6397.

Authors

N Altobelli¹, F Postberg², K Fiege³, M Trieloff⁴, H Kimura⁵, V J Sterken⁶, H-W Hsu⁷, J Hillier⁸, N Khawaja⁹, G Moragas-Klostermeyer⁹, J Blum¹⁰, M Burton¹¹, R Srama⁹, S Kempf⁷, E Gruen¹²

Affiliations

¹ European Space Agency, European Space Astronomy Centre, Madrid, Spain. nicolas.altobelli@sciops.esa.int.
² Institut für Geowissenschaften, University of Heidelberg, Heidelberg, Germany. Institut für Raumfahrtsysteme, University of Stuttgart, Stuttgart, Germany.
³ Institut für Geowissenschaften, University of Heidelberg, Heidelberg, Germany. Georgia Institute of Technology, School of Chemistry and Biochemistry, Atlanta, GA, USA.
⁴ Institut für Geowissenschaften, University of Heidelberg, Heidelberg, Germany. Klaus-Tschira-Labor für Kosmochemie, University of Heidelberg, Heidelberg, Germany.
⁵ Kobe University, Kobe, Hyōgo, Japan.
⁶ International Space Sciences Institute, Bern, Switzerland.
⁷ University of Boulder, Boulder, CO, USA.
⁸ University of Kent, Kent, UK.
⁹ Institut für Raumfahrtsysteme, University of Stuttgart, Stuttgart, Germany.
¹⁰ Technische Universität Braunschweig, Institut für Geophysik und Extraterrestrische Physik, Braunschweig, Germany.
¹¹ Jet Propulsion Laboratory, Pasadena, CA, USA.
¹² Institut für Geowissenschaften, University of Heidelberg, Heidelberg, Germany. Institut für Raumfahrtsysteme, University of Stuttgart, Stuttgart, Germany. University of Boulder, Boulder, CO, USA.

PMID: 27081064
DOI: 10.1126/science.aac6397

Abstract

Interstellar dust (ISD) is the condensed phase of the interstellar medium. In situ data from the Cosmic Dust Analyzer on board the Cassini spacecraft reveal that the Saturnian system is passed by ISD grains from our immediate interstellar neighborhood, the local interstellar cloud. We determine the mass distribution of 36 interstellar grains, their elemental composition, and a lower limit for the ISD flux at Saturn. Mass spectra and grain dynamics suggest the presence of magnesium-rich grains of silicate and oxide composition, partly with iron inclusions. Major rock-forming elements (magnesium, silicon, iron, and calcium) are present in cosmic abundances, with only small grain-to-grain variations, but sulfur and carbon are depleted. The ISD grains in the solar neighborhood appear to be homogenized, likely by repeated processing in the interstellar medium.

Publication types

Research Support, Non-U.S. Gov't