Correlation between insolation model and boulder deposits on the 67P/Churymov-Gerasimeko comet

Comets are considered the most fascinating and changing primordial objects of our solar system. They are not yet well understood, but they conserve important informations about the origin, the formation and the evolution of the solar system and all of its objects. From these considerations is born Rosetta, the European Space Agency mission, lanched in 2004, with the aim of study the composition, the chemical properties, the activity and the behaviour approaching the Sun during its perihelion, of 67P/Churyumov-Gerasimenko comet. The images of this short-period comet was taken in particular from OSIRIS, an Optical, Spectroscopic and Infrared Remote Imaging System onboard Rosetta. It revealed that the comet is characterized by two main lobes connected by a small neck, and that the surface is a collection of contrast, such as smooth plains or high fractured terrains. Very important features on the comet surface are the boulder deposits, i.e. positive reliefs detectable in different images with the constant presence of elongated shadows whose extension depends on the illumination geometry, and that seem to be detached from the ground where they stands. These objects are scattered all over the surface and they can be found both isolated or in cluster. In this thesis will be calculate the incidence and emission angles on some regions of the comet, the same areas studied by recent work in which it was calculated the size-frequency distribution of boulders with diameters ≥ 7m. In particular, the solar incidence angle will be involved to compute the total amount of absorbed solar energy for these different regions. The results show a trend between a high value of irradiation and high level of fracturing, but not for all of the regions analyzed.ope

Cometary science with CUBES

The proposed CUBES spectrograph for ESO's Very Large Telescope will be an exceptionally powerful instrument for the study of comets. The gas coma of a comet contains a large number of emission features in the near-UV range covered by CUBES (305-400 nm), which are diagnostic of the composition of the ices in its nucleus and the chemistry in the coma. Production rates and relative ratios between different species reveal how much ice is present and inform models of the conditions in the early solar system. In particular, CUBES will lead to advances in detection of water from very faint comets, revealing how much ice may be hidden in the main asteroid belt, and in measuring isotopic and molecular composition ratios in a much wider range of comets than currently possible, provide constraints on their formation temperatures. CUBES will also be sensitive to emissions from gaseous metals (e.g., FeI and NiI), which have recently been identified in comets and offer an entirely new area of investigation to understand these enigmatic objects.Comment: Accepted for publication in Experimental Astronom

BC-SIM-TR-013 - STC ICO1 REPORT Issue 1.0

The present document has been issued to describe the Instrument Check Out Phase (ICO#1) Tests of STC, channel of the Spectrometers and Imagers for MPO BepiColombo Integrated Observatory SYStem (SIMBIO-SYS)

Calathus: A sample-return mission to Ceres

Ceres, as revealed by NASA's Dawn spacecraft, is an ancient, crater-saturated body dominated by low-albedo clays. Yet, localised sites display a bright, carbonate mineralogy that may be as young as 2 Myr. The largest of these bright regions (faculae) are found in the 92 km Occator Crater, and would have formed by the eruption of alkaline brines from a subsurface reservoir of fluids. The internal structure and surface chemistry suggest that Ceres is an extant host for a number of the known prerequisites for terrestrial biota, and as such, represents an accessible insight into a potentially habitable “ocean world”. In this paper, the case and the means for a return mission to Ceres are outlined, presenting the Calathus mission to return to Earth a sample of the Occator Crater faculae for high-precision laboratory analyses. Calathus consists of an orbiter and a lander with an ascent module: the orbiter is equipped with a high-resolution camera, a thermal imager, and a radar; the lander contains a sampling arm, a camera, and an on-board gas chromatograph mass spectrometer; and the ascent module contains vessels for four cerean samples, collectively amounting to a maximum 40 g. Upon return to Earth, the samples would be characterised via high-precision analyses to understand the salt and organic composition of the Occator faculae, and from there to assess both the habitability and the evolution of a relict ocean world from the dawn of the Solar System.The attached document is the authors’ final accepted version of the journal article provided here with a Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) Creative Commons Licence. You are advised to consult the publisher’s version if you wish to cite from it.

CUBES : the Cassegrain U-band Efficient Spectrograph

In the era of Extremely Large Telescopes, the current generation of 8-10m facilities are likely to remain competitive at ground-UV wavelengths for the foreseeable future. The Cassegrain U-Band Efficient Spectrograph (CUBES) has been designed to provide high-efficiency (> 40%) observations in the near UV (305-400 nm requirement, 300-420 nm goal) at a spectral resolving power of R >20, 000 (with a lower-resolution, sky-limited mode of R ~7, 000). With the design focusing on maximizing the instrument throughput (ensuring a Signal to Noise Ratio (SNR) ~20 per high-resolution element at 313 nm for U ~18.5 mag objects in 1h of observations), it will offer new possibilities in many fields of astrophysics, providing access to key lines of stellar spectra: a tremendous diversity of iron-peak and heavy elements, lighter elements (in particular Beryllium) and light-element molecules (CO, CN, OH), as well as Balmer lines and the Balmer jump (particularly important for young stellar objects). The UV range is also critical in extragalactic studies: the circumgalactic medium of distant galaxies, the contribution of different types of sources to the cosmic UV background, the measurement of H2 and primordial Deuterium in a regime of relatively transparent intergalactic medium, and follow-up of explosive transients. The CUBES project completed a Phase A conceptual design in June 2021 and has now entered the detailed design and construction phase. First science operations are planned for 2028

Morphological and compositional analysis of boulder distributions on comet 67P/Churyumov-Gerasimenko

The European Space Agency's Rosetta mission consisted of the orbiter spacecraft Rosetta and the lander Philae. Launched in 2004, the space probe reached the comet 67P/Churyumov-Gerasimenko after a journey lasted more than ten years. The objectives of the mission were to map the comet, to study its composition, to investigate the chemical and thermal properties, and to monitor the activity during its journey in the inner Solar System. Rosetta was the first mission to rendezvous with a comet, and to deploy a lander on a comet's surface. From a wider prospective, the Rosetta mission allowed to investigate the origin of comets, and to define the implication for the origin of the Solar System. We used OSIRIS Narrow Angle Camera with a spatial scale smaller than 2 m=pixel to analyze the surface of comet 67P. The surface reveals a variety of terrains and geological features, suggesting to be a very active and complex environment. In the first part of the thesis, a detailed quantitative analysis of isolated boulder fields is provided. We used different techniques to supply a method for analyzing the morphology of the boulders, which represent one of the ubiquitous and most important geological features on the comet. In the second part, a method to measure the seasonal evolution of Hapi's deposit is described, providing an upper limit for Hapi's water ice fraction. Measuring the evolution of the heights of some boulders, we fixed the pristine 67P ice content, and we compared the results with the Inter-Stellar Medium and CI-Chondrites. Finally, we investigated the macroscopic thermomechanical behavior of a 40 meter boulder located on the Imhotep region by modeling its response to diurnal thermal forcing. Preliminary results reveal that stresses occur in the boulder's exteriors due to the sudden variation in temperature during sunset and sunrise. We explored whether the simulated stress is enough to propagate preexisting cracks, discussing the implications for rock breakdown

Mass movement reconstruction and boulder size-frequency distribution of the Simud Vallis landslide, Mars

International audienc

Modelling reconstruction and boulder size-frequency distribution of a young (<5 Myr) landslide located in Simud Vallis floor, Mars

International audienc