Origins of Solar System Dust beyond Jupiter

Abstract

The measurements of cosmic interplanetary dust by the instruments on board the Pioneer 10 and 11 spacecraft contain the dynamical signature of dust generated by Edgeworth-Kuiper Belt objects, as well as short period Oort Cloud comets and short period Jupiter family comets. While the dust concentration detected between Jupiter and Saturn is mainly due to the cometary components, the dust outside Saturn's orbit is dominated by grains originating from the Edgeworth-Kuiper Belt. In order to sustain a dust concentration that accounts for the Pioneer measurements, short period external Jupiter family comets, on orbits similar to comet 29P/Schwassmann-Wachmann-1, have to produce 8 × 10 4 g s −1 of dust grains with sizes between 0.01 and 6 mm. A sustained production rate of 3×10 5 g s −1 has to be provided by short period Oort cloud comets on 1P/Halley-like orbits. The comets can not, however, account for the dust flux measured outside Saturn's orbit. The measurements there can only be explained by a generation of dust grains in the Edgeworth-Kuiper belt by mutual collisions of the source objects and by impacts of interstellar dust grains onto the objects' surfaces. These processes have to release in total 5 × 10 7 g s −1 of dust from the Edgeworth Kuiper belt objects in order to account for the amount of dust found by Pioneer beyond Saturn, making the Edgeworth-Kuiper disk the brightest extended feature of the Solar System when observed from afar.

Dynamical Model for the Toroidal Sporadic Meteors

“…A steady-state population of several tens to a hundred of such comets would, in the long term, feed interplanetary space with sufficient dust for our findings. Additionally, modeling of direct dust detections beyond Jupiter requires a contribution from HTCs of about the same order of magnitude (e.g., Landgraf et al 2002). These independent studies support our results and validate our approach.…”

Direct detection of the Enceladus water torus withHerschel

“…The similar H 2 O fluxes per unit area into the four giant planets and Titan (Feuchtgruber et al 1997;Coustenis et al 1998;Moses et al 2000), combined with the rather constant dust flux (∼3×10 −18 g cm −2 s −1 ) measured in interplanetary space beyond 5 AU (Landgraf et al 2002) have been regarded as evidence that micrometeoroids -interplanetary (IDPs) or interstellar -are the dominant source (Moses et al 2000). Along with the evidence that the H 2 O present in Jupiter's atmosphere results from the Shoemaker-Levy 9 1994 impact -and that CO in Jupiter, Saturn, and Neptune Cavalié et al 2010;Lellouch et al 2005) also result from ancient cometary impacts -our inference that Enceladus is a quantitatively viable source of Saturn's water clearly shifts the paradigm towards local or sporadic sources playing a more important role.…”

“…The scarcity of primordial noble gases in Titan's atmosphere (Niemann et al 2010) tends to rule out cometary impacts as suppliers of volatiles there. Furthermore, based on the Landgraf et al (2002) dust fluxes and accounting for the gravitational focusing by Saturn at Titan's distance, we have found that the micro-meteoritic flux into Titan is in the range (0.1−0.7) × 10 6 mol cm −2 s −1 , depending on micrometeoroid velocity (i.e. their origin and orbit -interstellar, Halley-type or Kuiper Belt-like -see Moses et al 2000).…”

New Debris Disks around Nearby Main‐Sequence Stars: Impact on the Direct Detection of Planets

“…The ringlike structures seen in a number of resolved Spitzer disks, e.g., Fomalhaut (Stapelfeldt et al 2004) and Eri ( D. E. Backman et al 2006, in preparation), as well as in HST images ( Kalas et al 2005( Kalas et al , 2006, suggest that although the regions interior to the rings may not be completely empty due to a variety of mechanisms capable of transporting material inward from the outer disk (comets, Poynting-Robertson drag, interactions with planets, etc. ; Holmes et al 2002), these interior regions may have a quite low total optical depth, perhaps as low as the $20% contribution inferred for material from Kuiper Belt material to the total amount seen at 1 AU in our solar system (Landgraf et al 2002;Dermott & Kehoe 2004;Moro-Martín & Malhotra 2005).…”