Calendar

Abstract: For decades the Solar System has been our sole example of a planetary system, resulting in the classical view of planetary formation as a local, orderly process producing stable planetary systems. The ever growing sample of known exoplanets, however, has shown us the major role played by orbital migration and chaos in determining the evolution of planetary systems in our galaxy. This brought to questioning our very understanding of the history of the Solar System and to suggesting that it also could have undergone a more violent evolution than previously thought. In this talk I will describe how the compositional information on the planetary bodies of the Solar System can be used to shed new light on its past, illustrating the past and current investigations performed in the framework of the NASA missions Dawn and Juno, and I’ll discuss how the same principles, if not the same techniques, can be used to investigate of histories of extrasolar planets.

Abstract:
With significant new observing capabilities, centimeter-wavelength radio astronomy is currently in a renaissance leading up to the advent of the Square Kilometre Array (SKA). The sensitivity upgrades of both the NRAO Very Large Array (VLA) and the Very Long Baseline Array (VLBA) have begun to provide us with a much improved perspective on stellar centimeter radio emission, particularly concerning young stellar objects (YSOs) and ultracool dwarfs. For the first time we now have systematic access to the radio time domain. I will mainly present a deep VLA and VLBA radio survey of the Orion Nebula Cluster (ONC), where we have found hundreds of compact radio sources, a sevenfold increase over previous studies, and intricate detail on the radio emission of proplyds. We can now better disentangle thermal and nonthermal radio emission by assessing spectral indices, polarization, variability, and brightness temperatures (VLBA). With simultaneous radio-X-ray time domain information (Chandra), this project is providing first constraints on YSO radio flares and their relation with X-ray flares, as well as improved constraints on the overall high-energy irradiation of their surroundings, including protoplanetary disks. Starting with Orion, I will additionally discuss the use of the VLBA for precision stellar astrometry in the Gaia era, highlighting how VLBI astrometry is allowing us to extend the Gaia sample of YSOs and ultracool dwarfs by including embedded objects, distant obscured sources in the Galactic plane, and faint ultracool dwarfs, while providing important opportunities for astrometric cross-calibration.

Abstract. Negli ultimi anni, in corrisondenza di un certo rinnovato interesse per il medium fumetto e il suo uso con scopi didattici e divulgativi, sono stato coinvolto in progetti di vari committenti, tra i quali anche molti enti di ricerca scientifica (INAF, INFN, EVN, MAS, EUCLID, …), per produrre brevi storie che spiegassero l’astronomia a diverse tipologie di pubblico.

Al variare del committente e del suo pubblico di riferimento, ho dovuto quindi differenziare le strategie comunicative volte a coniugare al meglio le esigenze didattico-divulgative con altre di semplice vendibilità, nel caso di riviste e quotidiani, o, nel caso di enti scientifici, di promozione delle attività di ricerca.

I lavori già prodotti e quelli ai quali sto lavorando hanno così assunto vari caratteri: alcune storie sono di carattere storico, altre ne hanno uno più tecnico, altre ancora invece fanno leva sulla comunicazione emozionale nella quale il messaggio scientifico risulta piacevolmente diluito, sotterraneo, apparentemente secondario.

Per il pubblico dell’INSAP e del SEAC ho pensato di descrivere nel mio talk le linee generali delle strategie che ho via via adottato, soffermandomi in particolar modo sulla collaborazione con l’ente cileno Millenium de Astrofisica (M.A.S., http://www.astrofisicamas.cl) per il quale ho prodotto 8 brevi storie nelle quali spiego a fumetti altrettanti argomenti di astrofisica.

Il frame teorico nel quale una simile attività si colloca è quello oramai largamente studiato dei cosiddetti “concept comics”. Si tratta di un serio studio che affonda le sue basi nella epistemologia e nella sociologia della scienza e teso a mettere in luce i pro e i contro di un uso consapevole dei fumetti come strumenti per progettare una didattica e una divulgazione che siano al contempo scientificamente corrette e coinvolgenti così da obbedire ai precetti teorici del cosiddetto engagment, ultima frontiera in ambito pedagogico.

Il lavoro si basa sull’analisi di dati FLAMES dell’ammasso NGC 2264
nell’ambito della Gaia-ESO Survey. Lo scopo principale e’ lo studio
dei processi di accrescimento ed outflow nei membri dell’ammasso
dall’analisi dei profili della riga dell’Halpha e delle righe proibite
([SII] 6717/6731 A, [NII] 6548.05/6583.45 A). In clusters come NGC
2264 (ma anche in NGC 6530, Prisinzano et al. 2007, e NGC 6611, Bonito
et al. 2013, …), il contributo all’emissione in queste righe da
parte del cielo puo’ essere dominante. Discutero’ i problemi di una
cattiva sottrazione del contributo nebulare e come la formazione di
righe di assorbimento spurie puo’ essere usata per identificare le
sorgenti maggiormente affette dalla contaminazione dovuta al cielo.
Inoltre, illustrero’ come l’utilizzo di parametri alternativi a quelli
solitamente usati (Ha al 10% del picco o EW) come la FWZI possono dare
informazioni affidabili sugli accretori e sui moti del plasma in
infall/outflow nell’intorno della stella giovane.

ABSTRACT: The LSST survey will provide multi-epoch, multi-wavelength (u,g,r,i,z,y) mapping of the Southern Hemisphere, with a single-visit depth of r~24.5 and a gain of three magnitudes by the end of the program. This unprecedented spatial coverage will enable detection of young, pre-main sequence stars and stellar clusters down to distances of 5-10 kpc. A crucial and challenging step for spatial analyses of large stellar populations is measuring the extinction Av of individual objects. Multi-color photometry on a (r-i, g-r) or (i-J, r-i) diagram offers a direct solution to this issue for M-type stars: indeed, while the color locus of early-type (< K7) stars on these diagrams is parallel to the reddening vector, the color locus traced by M-type stars is tilted with respect to the reddening vector, which enables a straightforward and empirical measurement of their Av. By investigating the correlation between extinction and spatial properties of M-type stars in a given field, it is therefore possible to reconstruct the structure of the region and probe the nature of its population. In this study, we test the method on the NGC 2264 field. We selected a 2°x2° area centered on the NGC 2264 cluster, and collected the available r,i,J photometry from existing large-scale surveys (notably Pan-STARRS and UKIDSS). Then, assuming no prior knowledge on the nature of stars in the field, we used the (i-J, r-i) diagram to identify and deredden M-type stars in the sample, and the (r-i, r) + (RA, Dec) diagrams to investigate the nature and spatial distribution of stars as a function of their Av. We derived a non-uniform distribution of Av across the region, and could distinguish between a diffuse field population and a clustered stellar population toward the center of the field. An a posteriori comparison between the inferred spatial density map of the clustered population and the literature census of the NGC 2264 cluster enabled us to assess the performance of the method and its predictive capability.

Unveiling the many possible chemical routes through which life might have originated and evolved on early Earth is a task traditionally faced by means of peculiar experiments. However, in the last few years, state-of-the-art computational approaches have been put forward as powerful investigative tools in the wide spectrum of problems connected with the “origins of life” enigma. Advanced supercomputing techniques are nowadays able to simulate systems approaching the experimental complexity of a real sample, which they can model with the unprecedented reliability and precision conferred by Quantum Mechanics. In this way, avant-garde simulation methods such as ab initio molecular dynamics (AIMD), have suggested – with an atomistic detail – new chemical pathways for the synthesis of essential prebiotic species such as, e.g., amino acids [1].

Since ab initio simulations are nowadays capable to efficiently simulate disparate energy sources (i.e., electrical discharges [2], shock-waves mimicking meteoritic or grain impacts [3], high pressure/temperature regimes simulating hydrothermal conditions, UV radiation, etc.) most of the environments where life might have begun – both on Earth and in the outer space – can be reproduced to a high degree of reliability. Furthermore, novel metadynamics approaches [4] allow for the precise evaluation of the “plausibility degree” of each possible chemical pathway leading to the onset of prebiotically relevant molecules. This way, avant-garde computing educated with the laws of Density Functional Theory and Statistical Mechanics is able to reliably discern the most probable chemical route(s) within the a priori complex reaction network identifying a specific chemical transformation.

In this talk, after a brief examination of the basic concepts underlying those computational techniques, I will present disparate recent results gathered via advanced computing and that have offered novel insights not only in prebiotic chemistry but also in the more fundamental chemical physics scenario.

Il talk presenterà alcune figure femminili che hanno contribuito allo sviluppo della scienza astronomica, dalle origini al XX secolo, sottolineando alcuni aspetti che hanno favorito il loro approccio all’astronomia e alcune caratteristiche tipiche del loro contributo.

Ileana Chinnici (INAF – Osservatorio Astronomico di Palermo)

Abstract.

I will discuss how high spatial, spectral, and temporal resolution chromospheric/transition region/coronal observations coupled with detailed modeling can help us diagnose coronal heating properties in active region cores in non-flaring conditions.  I will focus on recent results from the Interface Region Imaging Spectrograph (IRIS), which provides us with unprecedented high spatial, temporal and spectral resolution observations of the chromosphere and transition region. Joint with coronal observations with Hinode (XRT and EIS), and SDO/AIA, these data cover from the upper photosphere to the corona.

In particular, I will discuss how IRIS observations of footpoints of hot active region loops, coupled with detailed HD and MHD modeling including chromosphere, transition region and corona, provide tight constraints on the coronal heating mechanisms in the core of active regions.

ABSTRACT: Elias 29 is a Class I star of the young star forming site of the Rho Ophiuchi Dark Cloud.In X-rays it shows a prominent fluorescent line at 6.4 keV which origin is still to be clearly understood. The excitation of fluorescence of cold material could be due to hard X-ray photons especially produced during flares or to high energy electrons. I will report on a recent joint and simultaneous XMM + NuSTAR of about 300 ks meant to investigate X-rays from soft to hard band (approx. 0.3-80 keV). In particular, I will discuss the analysis of a bright flare of modest duration (20 ks), the fluorescent emission and its variability and the hard X-ray emission in the NuSTAR band (10-80 keV).