Calendar

Speaker: Salvatore Colombo

Titolo: “Radiation hydrodynamic and magnetohydrodynamic models of plasma flows accreting onto Classical T Tauri Stars”

Abstract: “Secondo lo scenario più accettato, le stelle T Tauri sono stelle giovani che accrescono massa dal loro disco circumstellare.
L’obiettivo del mio dottorato è stato quello di studiare il fenomeno di accrescimento di massa in questi sistemi. Durante il mio seminario presenterò i risultati ottenuti durante i miei 3 anni di dottorato.
Mii focalizzerò sui risultati ottenuti da modelli di interazione tra l’attività stellare e il disco circumstellare e mostrerò come l’attività coronale possa dare origine a fenomeni di accrescimento.
Illustrerò i risultati ottenuti dallo studio della regione di impatto di una colonna di accrescimento sulla superficie stellare tenendo conto, per la prima volta in letteratura, del ruolo della radiazione in regime di non equilibrio termodinamico locale (non-LTE).  Per fare questo modello è stato necessario sviluppare un modulo non-LTE per il codice magnetoidrodinamico PLUTO. Presenterò il modulo e i test di validazione fatti.
Inoltre proverò che considerare il regime non-LTE ha importanti conseguenze sulla struttura e dinamica di una regione di shock.
Usando questo modulo ho dimostrato la presenza di un precursore radiativo nella colonna di accrescimento, formatosi per il riscaldamento del materiale che assorbe la radiazione proveniente dalla regione post-shock.
Durante la presentazione illustrerò le conseguenze del considerare il precursore nell’interpretazione delle osservazioni in banda UV e X. “

Speaker: A. Garrido (UNIPA)

Titolo: Analysis of exoplanetary atmospheres.

Abstract:

Speaker:  Darius Modirrousta Galian

Titolo: Theoretical exoplanetology

Seminario: Why does 55 Cancri e have a H/H 2 -rich atmosphere? Why is there a bimodal distribution of exoplanet radii with one peak at ~ 1.3R ⨁ , the other and ~ 2.4R ⨁ , and the minima at ~ 1.8R ⨁ .
Why do some airless magma ocean super-Earths have albedos close to ~ 50% when earth-based magmas have measured albedos of ~ 10%? Conversely, why are some hot Jupiters so dark with albedos of ~ 1% or below? New data from astronomical measurements shows that
the universe is far more complex and interesting than what traditional literature predicted. Understanding these bodies and phenomena is not a trivial task, but by coupling different scientific fields with observational data it may be possible to shed some light on these systems.

Speaker:  Ruggero Biondo

Titolo: Data-driven Numerical Reconstruction of the Interplanetary Parker Spiral

Abstract: Over the last decade the science community, governments and private partners have shown a growing interest in the topic of Space Weather: a broad discipline aimed to the forecasting of potential threats to space and ground-based systems and operations. The ability of the state-of-art codes to reconstruct the stationary conditions of the interplanetary plasma is still limited, as shown by the comparisons between model predictions and in-situ measurements acquired by various spacecrafts. Therefore, it is necessary to develop leaner codes and to improve the agreement between forecasts and observed data on the other. The aim of this work is to lighten the procedures involved in determining the inner heliospheric boundary and to bind the numerical simulations to direct measurements of the parameters of the interplanetary plasma. To do this, the ambient plasma parameters of the inner heliosphere are reconstructed, using the 1 AU data provided by the Solar Physics Group in INAF-Turin Astrophysical Observatory from different spacecrafts located in the lagrangian point L1 such as DSCOVR and GGS Wind, by going backwards to 0.1 AU following the spiraling arms of the Interplanetary Parker Spiral. The back-reconstructed plasma parameter at 0.1 AU are thus employed as inner boundary conditions for the solar wind expansion up to 1 AU based on a MHD simulation. This innovative approach provides a new method to reconstruct the conditions of the interplanetary plasma from the Sun to 1 AU and beyond

Speaker: Giuseppe Morello

Titolo: Towards high-precision modeling of star+exoplanet multiwavelength light-curves

Abstract: I will present new tools and methodologies purposely developed for modeling observations of transiting exoplanets and eclipsing binaries with precision down to <10 parts per million (ppm).

ExoTETHyS is a python package that aims to collect the functions needed to model the high-precision spectrophotometric observations obtained with JWST and ARIEL (not only). The current version includes a user-friendly stellar limb-darkening calculator that outperforms existing codes by one order of magnitude in terms of light-curve model accuracy. I will introduce to the current use of ExoTETHyS and discuss the planned developments.

I will also show the results from the consistent reanalyses of Spitzer and Hubble data with bayesian approaches and improved data detrending techniques.

Speaker: Fabio Reale (UNIPA)

Authors: F. Reale(1,2), P. Testa(3), A. Petralia(2), D. Graham(4), D. Kolotkov(5)
(1) Dipartimento di Fisica & Chimica, Università di Palermo;
(2) INAF-Osservatorio Astronomico di Palermo;
(3) Center for Astrophysics | Harvard & Smithsonian, Cambridge, USA;
(4) Bay Area Environmental Research Institute, NASA Research Park, Moffett Field, USA;
(5) Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry, UK

Titolo: Impulsive heating in the solar corona: large scale magnetic rearrangements

Abstract:

Speaker: Massimo Brescia (INAF-Osservatorio Asstronomico di Capodimonte).

Titolo: Leverage data science in modern astrophysics
Abstract:
The exploration of the Universe is one of main topics within the research in Physics Sciences. All incoming and on going astrophysical surveys are characterized by a huge amount of heterogeneous multi-wavelength data, which will require efficient automatic methods to be exploited in an optimal and competitive way by the italian scientific community.
Astrophysics data are then characterized by large volume, velocity and
variety, the three conditions at thebase of the Big Data paradigm. Therefore, an approach based on data mining, statistics,
machine and deep learning, in one word Astroinformatics, is required. We
will discuss a variety of such methodologies, already available and validated in several astrophysical contexts, with  the aim at proposing a pragmatic
way to approach the scientific topics of the incoming multi-messenger
Astrophysics.

Speaker: Elisa Guerriero (UNIPA)

Titolo: Development polishing process for bare aluminum mirrors to ARIEL space mission

Abstract: ARIEL is the 4th medium-class mission of ESA’s Cosmic Vision Programme to see and to study the exoplanets’ atmospheres in VIS/IR. The technical innovation of the project is the use of bare aluminum for the mirrors. This material is light, cheap, and available in large quantities, but difficult to polish because it is not very dense. In this seminar, I will talk about my work at Media Lario S.r.l. for the development of the aluminum polishing process, the critical issues and the results obtained.

Speaker: Darius Modirrousta Galian (UNIPA)

Titolo: Exploring Super-Earth Surfaces: Albedo of Near-Airless Magma Ocean Planets and Topography

Abstract:

Speaker: Salvatore Sciortino (INAF)

Titolo: A prototype Palermo- Wavelet Detection Code for the
ATHENA WFI: investigating the effect on detection of telescope (or lack of) baffle
and other new challenges posed by very deep exposures of a large area telescope

Abstract:

I will discuss the motivations for and the initial results of a prototype
version of the so-called Pwedetect code for the Athena WFI.  I will discuss the
use of this prototype for assessing the effect of stray-light in the detection
of weak sources with Athena and results from an on-going extensive set of
simulations that have already pinpoint some of the new challenges that the WFI
poses with respect to the past and current generation of X-ray imaging detectors.