Nanodust Detection between 1 and 5 AU Using Cassini Wave Measurements (original) (raw)
NASA/ADS
;
- Meyer-Vernet, N. ;
- Lecacheux, A. ;
- Belheouane, S. ;
- Moncuquet, M. ;
- Kurth, W. S. ;
- Mann, I. ;
- Mitchell, D. G. ;
- André, N.
Abstract
The solar system contains solids of all sizes, ranging from kilometer-sized bodies to nano-sized particles. Nanograins have been detected in situ in the Earth's atmosphere, near cometary and giant planet environments, and more recently in the solar wind at 1 AU. The latter nanograins are thought to be formed in the inner solar system dust cloud, mainly through the collisional break-up of larger grains, and are then picked up and accelerated by the magnetized solar wind because of their large charge-to-mass ratio. In the present paper, we analyze the low frequency bursty noise identified in the Cassini radio and plasma wave data during the spacecraft cruise phase inside Jupiter's orbit. The magnitude, spectral shape, and waveform of this broadband noise are consistent with the signatures of the nano particles that traveled at solar wind speed and impinged on the spacecraft surface. Nanoparticles were observed whenever the radio instrument was turned on and able to detect them at different heliocentric distances between Earth and Jupiter, suggesting their ubiquitous presence in the heliosphere. We analyzed the radial dependence of the nanodust flux with heliospheric distance and found that it is consistent with the dynamics of nanodust originating from the inner heliosphere and picked up by the solar wind. The contribution of the nanodust produced in the asteroid belt appears to be negligible compared to the trapping region in the inner heliosphere. In contrast, further out, nanodust is mainly produced by the volcanism of active moons such as Io and Enceladus.
Publication:
The Astrophysical Journal
Pub Date:
June 2015
DOI:
arXiv:
Bibcode:
Keywords:
- interplanetary medium;
- Sun: heliosphere;
- Astrophysics - Earth and Planetary Astrophysics
E-Print:
to appear in ApJ