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- Cremonese, G., et al.
(author)
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Photometry of dust grains of comet 67P and connection with nucleus regions
- 2016
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In: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 588
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Journal article (peer-reviewed)abstract
- Aims. Multiple pairs of high-resolution images of the dust coma of comet 67P/Churyumov-Gerasimenko have been collected by OSIRIS onboard Rosetta allowing extraction and analysis of dust grain tracks. Methods. We developed a quasi automatic method to recognize and to extract dust tracks in the Osiris images providing size, FWHM and photometric data. The dust tracks characterized by a low signal-to-noise ratio were checked manually. We performed the photometric analysis of 70 dust grain tracks observed on two different Narrow Angle Camera images in the two filters F24 and F28, centered at lambda = 480.7 nm and at lambda = 743.7 nm, respectively, deriving the color and the reddening of each one. We then extracted several images of the nucleus observed with the same filters and with the same phase angle to be compared with the dust grain reddening. Results. Most of the dust grain reddening is very similar to the nucleus values, confirming they come from the surface or subsurface layer. The histogram of the dust grain reddening has a secondary peak at negative values and shows some grains with values higher than the nucleus, suggesting a different composition from the surface grains. One hypothesis comes from the negative values point at the presence of hydrated minerals in the comet.
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2. |
- Scandariato, G., et al.
(author)
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CHEOPS (CHaracterizing ExOPlanets Satellite) Mission
- 2016
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In: Proceedings of Science. - 1824-8039. ; 2016-May
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Journal article (peer-reviewed)abstract
- The Characterizing ExOPlanet Satellite (CHEOPS) mission was selected in October 2012 by ESA as the first small mission. It will be a ultra-high precision photometer dedicated to the observation of transits of known exoplanets on bright stars, for which the mass has already been measured via ground-based spectroscopic surveys. Its precision will allow the accurate determination of the planetary radii and, by consequence, the planetary bulk density. CHEOPS will also unveil transiting exoplanets of interest for in-depth characterization, a legacy for future instruments suited to the spectroscopic characterization of exoplanetary atmospheres.
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