The solar system

Theoretical modeling of the scattering properties of comet 67P/Churyumov-Gerasimenko's dust in the comaand on the nucleus surface.
I. Bertini, M. Lazzarin, F. La Forgia.

Dust is proved to be the main constituent in comets, the most primitive objects of our solar system.
The study of its properties is therefore pivotal in understanding the original materials which formed planets, small bodies, and moons. The OSIRIS Rosetta instrument took more than 80,000 multiwavelength images of 67P/Churyumov-Gerasimenko during the two-years orbiting period around the comet. These images allow the measurements of the scattering properties of dust (essentially the phase function and the colors) both in the cometary atmosphere and on the nucleus. In order to derive hints on the intimate nature of cometary dust (i.e. its shape, size, composition, and size distribution)  from the remote sensing  observed parameters, a theoretical modeling is necessary.
The PhD student will have access to the large OSIRIS database through our team which is deeply involved in the project and will have to apply innovative scattering codes (e.g. DDSCAT, T-Matrix) to define which properties of the dust are determining the scattering observables. Moreover, experiences in scattering laboratories of the Institute of Astrophysics of Andalucia, Spain (2D lab) and of the Physics Department of the University of Bern, Switzerland (3D lab), are foreseen to test and validate the outputs of the theoretical modeling with practical laboratory results. The thesis will have as external co-supervisors F. Moreno and O. Munoz (IAA Spain), and N. Thomas and A. Pommerol (UniBern)
 
Modeling and analysis of Mars and Mercury surfaces
G.Cremonese, A.Lucchetti

On March 2016, the European Space Agency (ESA) in collaboration with Russian federal space agency (Roscosmos) launched the Exomars Trace Gas Orbiter (TGO) having on board the stereo visible imaging system CaSSIS (Colour and Stereo Surface Imaging System). Our team has been involved in the realization of the instrument and in the scientific analysis, which includes observations planning, Digital Terrain Models (DTM) generation and target selection.
In addition, our team has the responsibility of the SIMBIO-SYS instrument (Spectrometers and Imagers fro MPO BepiColombo integrated observatory system) on board the upcoming ESA/JAXA BepiColombo mission, which will be launched in October 2018 toward the innermost planet Mercury. SIMBIO-SYS will provide high resolution and stereo visible images and Vis-NIR spectra of the entire surface of the planet.
In this framework, the PhD student will conduct analysis of the surfaces of Mars and Mercury using data coming from ExoMars TGO, which will be operative around Mars at the beginning of 2018, and from NASA/MESSENGER mission in preparation to the upcoming BepiColombo mission. Specifically, the candidate will be able to investigate different surface processes and conduct geomorphological analysis of a wide variety of landforms characterizing the planets’ surface. He/She will be included in a team that is already carrying on surface analysis according to specific subjects, as impact processes, search for water traces, hollows, volcanic activity and so on.

3D analysis of planetary surfaces
G.Cremonese, A.Lucchetti, C.Re

In the last decades the space missions of any space agencies toward planets or minor bodies have on board a stereo camera or an imaging system in order to 3D reconstruct the surface of the studied body. After the first experience in acquiring 3D images of the Moon and Mars, the planetary scientists have realized the plenty of more information they may get on the studied body.
However, the elaboration and the analysis of stereo images, in order to generate a Digital Terrain Model, is very complex starting from the design of the imaging system and requirements to the satellite in terms of resources and operations.
Our team is involved in the design and realization of a new concept of stereo camera, which also includes a new method of stereo acquisition for the  ESA BepiColombo and ExoMars missions. In addition, our team is working on developing an advanced concept of stereo camera including the hyperspectral information.
The PhD student will be involved in the analysis of stereo images of Mars acquired by the CaSSIS imager on board the ExoMars TGO mission, he/she will contribute in the development of new software and tools to analyze stereo data and in the design of new stereo cameras.

Volatiles in comets
M. Lazzarin , F. La Forgia, I. Bertini

The Solar System formed from a primordial molecular cloud in physical conditions that are still subject of great debate. The most primordial objects of the Solar System are comets, which formed very early at very low temperatures and slowly accumulated ices for a long time. Comets retain thus great amounts of primordial volatiles and supervolatiles such as water, carbon monoxide, and oxygen that conceal crucial physical parameters such as the temperature formation and the relative composition of the primordial molecular cloud. The PhD project focuses on the spectral analysis of the volatiles released by comets. Data available from Rosetta mission (comet 67P/Churyumov-Gerasimenko), other space missions such as Deep Impact (comet 1P/Tempel1 and 103P/Hartley 2) and ground-based data (from Asiagoand other observing proposal to be submitted) will be used for the purpose. Combined fluorescence and coma models for various molecules at a wide range of wavelengths together with the modelling of numerous chemical reactions acting in extreme conditions are necessary to interpret the data and build a complete scenario of how volatiles behave in comets.
This PhD project will be performed in collaboration also with Dr. Dennis Bodewits of the University of Maryland-USA that could act as external supervisor.

Spectroscopic Investigation of Near Earth Objects
M. Lazzarin, F. La Forgia, I. Bertini

This PhD thesis is connected with an ongoing project named SINEO, Spectroscopic Investigation of Near Earth Objects (NEOs). NEOs  represent  one  of the  most peculiar  populations  of  Solar System small bodies.  Their origin and their link with the other minor bodies of the Solar System are still a matter of debate. Moreover they represent a real threat for our planet. The  population appears  heterogeneous  in all  the aspects of its physical  properties and they are also very interesting mineralogical sources and only 5% of NEO with known orbits  (about 15500) are taxonomically classified. During the PhD, proposals to telescopes such as TNG or NTT, VLT and also Asiago will be prepared and submitted to spectroscopically observe NEOs in the visible and near infrared region. In the meanwhile more than 100 spectra are already available for reduction and analysis from TNG adn NTT telescopes. Some of the objectives are:
•       Investigate in  detail  the  surface  composition  of the  objectsand  make  a correspondence between taxonomic type and surface mineralogy
•       Search  for  meteorite  parent  bodies  among  NEOs.
•       Investigate the space weathering effects on S-type, C-type and D-type asteroids.
•       Investigate NEOs with peculiar  dynamical properties (e.g. Tisserand invariant<3)   in   order   to   contribute   to   the identification  of possible  NEO  of cometary  origin.
This work will be performed also in collaboration with the ESA-NEOCC center (Roma, Dr. Ettore Perozzi, Dr. Marco Micheli), with ESA-Space Situationa Awareness (Dr. Detlef Koschny), with Dr. Cristina Dalle Ore NASA-Ames and with Prof. Mauro Barbieri Universita’ de Atacama.