———————– YEAR 2016 ———————–
30-11-2016, ore 11:00, Aula IB09 ARTOV
Francesca Zambon (INAF-IAPS)
Mercury after MESSENGER: preliminary analysis in support to BepiColombo mission
Abstract: The planet Mercury has been explored by two space missions so far. Because of its harsh thermal environment, close exploration of Mercury is challenging. The NASA Mariner 10 spacecraft was the first one to acquire remote sensing data of this planet, back in 1974. Mariner 10 covered 45% of the surface during three Hermean flybys. In recent times, the NASA MESSENGER mission globally mapped the planet and contributed in understanding several unsolved issues on Mercury’s origin, its surface structure, and the nature of its magnetic field, exosphere, and magnetosphere. Nevertheless, after MESSENGER, the surface composition is still debated, and the correlation between morphology and compositional heterogeneity is far from being fully understood.
The Mercury Dual Imaging System (MDIS) onboard MESSENGER achieved global coverage of Mercury’s surface with varying spatial resolution. The surface of Mercury shows differences in composition associated to variations in the spectral slope. By analyzing the spectral slope, relative reflectance, and morphology, three major terrain units have been identified: smooth plains, intermediate terrain, and low-reflectance material.
The mapping process permits integration of different geological surface information, which is required to better understand the planet crust formation and evolution. Our work focuses on the search for a possible connection between the different morpho-stratigraphic units and compositional units. Merging data from different instruments provides additional information about lithological composition, which is key to the achievement of a geochemical map.
The ESA BepiColombo mission, due to be launched in 2018, has an innovative, highly integrated remote sensing package: Spectrometers and Imagers for MPO BepiColombo Integrated Observatory SYStem (SIMBIO-SYS). The VIHI channel of SIMBIO-SYS will enable acquisition of hyperspectral data with enhanced spatial resolution and in a larger wavelength range compared to similar instrumentation flown onboard MESSENGER, meant to improve our knowledge of Mercury’s surface from a geological and compositional standpoint. In addition to this, the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) and the Mercury Imaging X-ray Spectrometer (MIXS) onboard BepiColombo are also expected to obtain global mapping of the surface. These data may be combined to those returned by SIMBIO-SYS to ultimately achieve a complete geochemical map of Mercury.
10-11-2016, ore 11:00, aula IB09, ARTOV
Vito Francesco Polcaro (INAF-IAPS)
I “Campanari”: un calendario di pietra della Prima Età del Bronzo nella Sicilia Occidentale
Abstract: In provincia di Palermo, all’interno dei confini comunali delle cittadine di San Cipirello e Monreale, ci sono due grandi rocce con fori indubbiamente artificiali, entrambe chiamato localmente “Campanaru” (cioè “campanile”) e poste a meno di otto chilometri l’una dall’altra. Entrambi i fori sono orientati astronomicamente con estrema precisione: la prima roccia, situata sul Monte Arcivocalotto, ha l’asse del suo foro allineato con il sorgere del Sole al solstizio d’inverno, mentre l’altra, situata sulla collina di Cozzo Perciata, punta esattamente al sorgere del Sole del solstizio d’estate. Per quest’ultima esisteva ancora fino a poco tempo fa la tradizione che metteva in relazione il sorgere del Sole nel foro con l’inizio dei lavori di mietitura. Vicino ad entrambi questi megaliti, è archeologicamente ben attestata la presenza di un insediamento datato all’Eneolitico/Prima Età del Bronzo. Gli assi dei fori in entrambe le rocce puntano, da direzioni opposte, a Pizzo Pietralunga, una eccezionale struttura geologica isolata, alla cui base è situato un altro sito dell’Eneolitico/Prima Età del Bronzo, probabilmente di carattere cultuale e / o di scambio delle popolazioni locali. Il fatto che in questa zona ci siano due monumenti coevi e simili (rocce perforate artificialmente) con allineamenti diverse e complementari (solstizio invernale ed estivo) indica che qui, tra l’Eneolitico e la Prima Età del Bronzo, si è sviluppata una civiltà che aveva un calendario solare ed ha sviluppato una tecnologia semplice ma molto efficace per materializzarlo. Altri monumenti megalitici, come il cosiddetto ” Pulpito del Re ” nel vicino parco del Bosco della Ficuzza, risalenti allo stesso periodo e che mostrano ierofanie sorprendenti al sorgere del sole ai solstizi, suggeriscono quale sia stata questa civiltà.
6-10-2016, ore 11:00, Aula IB09, ARTOV
Alberto Adriani (INAF-IAPS)
Juno: Missione a Giove. I primi risultati.
Abstract: La missione Juno a Giove si prefigge di svelare molti dei segreti ancora irrisolti del pianeta più grande del sistema solare. La sonda è equipaggiata con strumenti che permettono lo studio del pianeta in tutti i suoi aspetti dalla magnetosfera che lo circonda fino al suo interno. Verranno illustrate le motivazioni, gli obiettivi scientifici della missione e mostrati i primi dati raccolti durante il primo passaggio in prossimità del pianeta dallo strumento italiano JIRAM, Jovian InfraRed Auroral Mapper.
8-04-2016, 11.00, Aula IB09, ARTOV
Dr.ssa Kazi Rygl (IRA – INAF)
ALMA Cycle 4 Capabilities
Abstract: The Atacama Large Millimeter/submillimeter Array (ALMA) is a complete imaging and spectroscopic instrument operating at frequencies from 84GHz to 950GHz (3mm – 0.3mm). Located on Chajnantor plain of the Chilean Andes, ALMA is the most powerful millimeter/submillimeter interferometer on Earth consisting of two arrays which are sensitive to different angular scales to provide scientists with the best possible sky brightness representation of their targets. I will present the ALMA capabilities offered for the Cycle 4 proposal call, give some examples of science with ALMA cycle 4 observations, and show a brief overview of the Cycle 4 Observing Tool.
08-03-2016, 14:30, Aula IB09, ARTOV
Prof. Yukihiro Takahashi (SMC – Hokkaido University)
Lightning and cloud observations in Venus and Jupiter with spacecraft and ground-telescope
Abstract: Lightning process is an excellent tool to explore the planetary atmosphere through the knowledge of the relationship between the atmospheric dynamics and electrical charge.
It has been suggested for a decade that thunderstorms in Jupiter’s atmosphere take important roles not only in the investigation of meteorology, which determines the large scale structures such as belt/zone and big ovals, but also in probing the water abundance of the deep atmosphere, which is crucial to constrain the behavior of volatiles in early solar system.
Here we suggest making observation of thunderstorm activity using lightning flash detection and cloud imagery with JUICE spacecraft and ground-based telescopes. Observing H Balmer Alpha line (656.3nm), we could estimate the activities of thunderstorms quantitatively, which enables us to investigate the mechanism of large structure formation.
As for the lightning activity in Venus, even though extensive investigations using data obtained with spacecraft and ground-based telescopes have been carried out, we don’t reach consensus on the existence of lightning in that planet. Indeed there exist some strong indications of electrical discharge both in optical and radio wave measurements. But these “evidences” are sometimes not accepted in the majority of researcher community. For example, it is reported that the magnetometer on board Venus Express recorded whistler mode waves whose source could be lightning discharge occurring well below the spacecraft.
LAC is the first sensor designed for the lightning detection in Venus. In order to identify the optical flash caused by electrical discharge in the atmosphere of Venus, at least, with an optical intensity of 1/10 of the average lightning in the Earth, we built a high-speed optical detector, LAC (Lightning and Airglow Camera), on board Akatsuki spacecraft. Unique performance of LAC compared to other equipments is the high-speed sampling rate at 32 us interval for all 32 pixels of APD matrix, enabling us to distinguish the optical lightning flash from other pulsing noises. We selected OI 777 nm line, the most expected emissions in CO2 atmosphere based on the laboratory experiment. After orbit insertion of Akatsuki, the elongated orbit allows umbra for ~30 min to observe the lightning flash in the night side of Venus every ~10 days after April 2016. Here we would report the instrumental status of LAC and the testing result together with future plans and strategy of LAC operation.