• DOI:10.3847/0004-637X/821/1/19
• Corpus ID: 125072014

EVOLUTION OF THE DUST SIZE DISTRIBUTION OF COMET 67P/CHURYUMOV–GERASIMENKO FROM 2.2 au TO PERIHELION

@article{Fulle2016EVOLUTIONOT,
  title={EVOLUTION OF THE DUST SIZE DISTRIBUTION OF COMET 67P/CHURYUMOV–GERASIMENKO FROM 2.2 au TO PERIHELION},
  author={Marco Fulle and Francesco Marzari and Vincenzo Della Corte and Sonia Fornasier and Holger Sierks and Alessandra Rotundi and Cesare Barbieri and Philippe Lamy and R. Rodrigo and Detlef Koschny and Hans Rickman and H. Uwe Keller and J{\'o}se Juan Lopez‐Moreno and Mario Accolla and Jessica Agarwal and Michael F. A’Hearn and Nico Altobelli and Maria Antonietta Barucci and J L Bertaux and I. Bertini and Dennis Bodewits and Ezio Bussoletti and L. Colangeli and Massimo Cosi and Gabriele Cremonese and Jean François Crifo and Vania Da Deppo and Bj{\"o}rn J R Davidsson and Stefano Debei and Mariolino De Cecco and Francesca Esposito and Marco Ferrari and Frank Giovane and Bo Ake Sture Gustafson and Simon F. Green and O. Groussin and E. Gr{\"u}n and Pedro J. Guti{\'e}rrez and C. G{\"u}ttler and M Herranz and S. F. Hviid and Wing Ip and Stavro Lambrov Ivanovski and J. M. Jer{\'o}nimo and L. Jorda and J. Knollenberg and Rainer Kramm and E. K{\"u}hrt and Michael K{\"u}ppers and L. M. Lara and Monica Lazzarin and Mark R. Leese and A. C. L{\'o}pez-Jim{\'e}nez and Francesca Lucarelli and E. Mazzotta Epifani and John McDonnell and Vito Mennella and A. Molina and Rafael Talero Morales and Fernando Moreno and Stefano Mottola and G. Naletto and N. Oklay and Jos{\'e} Luis Ortiz and Ernesto Palomba and Pasquale Palumbo and James M. Perrin and Frans J. M. Rietmeijer and J. Rodr{\'i}guez and R. Sordini and N. Thomas and C. Tubiana and J.‐B. Vincent and Paul R. Weissman and K-P. Wenzel and Vladimir V. Zakharov and John C. Zarnecki},
  journal={The Astrophysical Journal},
  year={2016},
  volume={821}
}

• M. Fulle, F. Marzari, +74 authors J. Zarnecki
• Published 5 April 2016
• Physics, Geology
• The Astrophysical Journal

The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov–Gerasimenko, has been detecting individual dust particles of mass larger than 10−10 kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time. The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from models of 67P’s trail. At sizes <1 mm, the size distribution observed by GIADA shows a strong time evolution, with a differential power index drifting from −2 beyond 2 au to −3.7 at perihelion, in agreement with the evolution derived from coma and tail models based on ground-based data. The refractory-to-water mass ratio of the nucleus is close to six during the entire inbound orbit and at perihelion.