Ulysses spacecraft in situ detections of cometary dust trails

Abstract

The Ulysses spacecraft was launched in 1990 and, after a Jupiter swing-by in 1992, became the first interplanetary spacecraft orbiting the Sun on a highly inclined trajectory with an inclination of 79 ∘ . The spacecraft was equipped with an impact ionization dust detector which provided 17 years of in situ dust measurements in interplanetary space from 1990 to 2007. Cometary meteoroid streams (also referred to as trails) exist along the orbits of comets, forming fine structures of the interplanetary dust cloud. We use the Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model (Soja RH et al . 2015 Characteristics of the dust trail of 67P/Churyumov-Gerasimenko: an application of the IMEX model. Astron. Astrophys. 583 , A18. (doi: 10.1051/0004-6361/201526184 )) to predict cometary stream traverses by Ulysses and re-analyse the Ulysses dust dataset in order to identify impacts of cometary stream particles detected during such trail traverses. We identify 19 particles compatible with three Ulysses trail traverses on 12 March 1995, 25–27 April 2001 and 16–19 May 2001. The particle origin is compatible with up to five comets, i.e. 10P/Tempel 2, 146P/Shoemaker-LINEAR, 267P/LONEOS and possibly 45P/Honda-Mrkos-Pajdušáková and P/1999 RO28 (LONEOS). We find a dust spatial density in these trails of approximately 2 − 7 ⋅ 10 − 8 m − 3 . The radii of the detected cometary stream particles derived from the dust instrument calibration are in the micrometre range. The in situ analysis of meteoroid trail particles in space, which can be traced back to their source bodies, opens a new opportunity for remote compositional analysis of comets and asteroids without the necessity to send a spacecraft to or even land on these celestial bodies, opening new opportunities for future space missions equipped with in situ dust analyzers. This article is part of the theme issue 'Dust in the Solar System and beyond'.