A&A 503, 259-264 (2009)
DOI: 10.1051/0004-6361/200912080

Statistical analysis of micrometeoroids flux on Mercury

P. Borin^{1, 2}, G. Cremonese², F. Marzari³, M. Bruno⁴, and S. Marchi<sup>5

1</sup>  CISAS, University of Padova, via Venezia 15, 35131 Padova, Italy
    e-mail: patrizia.borin@unipd.it
²  INAF – Astronomical Observatory of Padova, Vicolo dell'Osservatorio 5, 35131 Padova, Italy
    e-mail: gabriele.cremonese@oapd.inaf.it
³  Department of Physics, via Marzolo 8, 35131 Padova, Italy
    e-mail: marzari@pd.infn.it
⁴  Department of Mineralogical and Petrological Science, via Valperga Caluso 35, 10125 Torino, Italy
    e-mail: marco.bruno@unito.it
⁵  Department of Astronomy, Vicolo ell'Osservatorio 5, 35131 Padova, Italy
    e-mail: simone.marchi@unipd.it

Received 16 March 2009 / Accepted 21 May 2009

Abstract
Context. Meteoroid impacts are an important source of neutral atoms in the exosphere of Mercury. Impacting particles of size smaller than 1 cm have been proposed to be the major contribution to exospheric gases. However, our knowledge of the fluxes and impact velocities of different sizes is based on old extrapolations of similar quantities on Earth.
Aims. We compute by means of N-body numerical integrations the orbital evolution of a large number of dust particles supposedly produced in the Main Belt. They migrate inward under the effect of drag forces until they encounter a terrestrial planet or eventually fall into the Sun. From our numerical simulations, we compute the flux of particles hitting Mercury's surface and the corresponding distribution of impact velocities.
Methods. The orbital evolution of dust particles of different sizes is computed with a numerical code based on a physical model developed previously by Marzari & Vanzani (1994, A&A, 283, 275). It includes the effects of Poynting-Robertson drag, solar wind drag, and planetary perturbations. A precise calibration of the particle flux on Mercury has been performed by comparing our model predictions for dust infall on to Earth with observational data.
Results. We provide predictions of the flux to different size particles impacting Mercury and their collisional velocity distribution. We compare our results with previous estimates and we find that these collisional velocities are lower but that the fluxes are significantly higher.

Key words: methods: N-body simulations -- methods: statistical -- meteors, meteoroids -- planets and satellites: individual: Mercury

© ESO 2009

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

• If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
• You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
• You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.