Planet formation in the solar system and abroad.

Seminar by

Dr. Bertram Bitsch-

Max Planck Institute for Astronomy

ABSTRACT: Planet formation theories were inspired in the past by our own solar system, but the detection of exoplanets have further challenged our understanding of planet formation - especially the classes of planets we do not host in our own solar system like close-in super-Earths and hot Jupiters. A good planet formation theory thus has to explain the formation of the solar system as well as the formation of exoplanetary systems.

In the core accretion scenario, a planetary core of several earth masses forms first by accreting pebbles and/or planetesimals before it can start to accrete gas. In the pebble accretion scenario, this transition in the accretion regime is linked to the pebble isolation mass, the mass at which growing planets open partial gaps in their protoplanetary disc - a so-called pressure bump - and block the inward flux of pebbles, allowing the planetary atmosphere to cool, contract and grow. The blocking of pebbles does not only influence the growing planet, but also the disc interior to the planet, which is starved of material, resulting in reduced growth of inner planets. In this talk, I will first introduce the concepts relevant for planetary growth (e.g. pebble growth and drift, pebble accretion, planetesimal formation). I will then focus on how drifting pebbles (and their blocking) can help to explain constraints in the solar system (carbonaceous vs. non carbonaceous chondrites) and for exoplanets.

Tuesday, May 31th 2022, at 14:30

Live on Google Meets

PLATO: The ESA M3 Mission

Seminar by

Dr. Isabella Pagano-

Director of the Astrophysical Observatory of Catania

ABSTRACT: PLAnetary Transits and Oscillations of stars (PLATO) is the 3rd medium-size (M3) mission in the ESA Cosmic Vision 2015-2025 program. With its 26 all-refractive telescopes onboard, PLATO secures a FoV of more than 2100 square degrees, allowing us to search for Earth-sized planets in the habitable zone of solar-type bright stars.

The selected range of target luminosities is key to allow follow-up investigations on the detected exo-planetary systems, from RV follow-up, to asteroseismology studies that provide increased precision on the mass of discovered planets. Moreover, bright stellar targets are best cases when studying atmospheres of transiting planets by spectroscopy from space (JWST, Ariel) and from the ground (e.g., Espresso@VLT, Hires@ELT). PLATO is planned for a launch to L2 at the end of 2026.

I will focus my talk on some of the PLATO science cases, and will give an overview on how the instrument and the mission work.

Thursday, February 3rd 2022, at 16:00

Live on Google Meets

Neural networks for photometric data

Seminar by

Dr. Gregory Olmschenk -

NASA GSFC, Baltimore, MD

ABSTRACT: While the rapid growth in astrophysical data output presents immense opportunities for discoveries, it also presents a challenge: How to effectively and efficiently search the data for relevant information. Neural networks offer a compelling method to accomplish this search. In this presentation, we will explain why neural networks are valuable and provide an intuitive understanding of how neural networks understand data. We will show our recent results identifying 181 new planet candidates in TESS data using a neural network pipeline, examine the obstacles in training neural networks for such photometric data, and discuss methods to overcome these obstacles.

Friday, June 25th, at 16:00

Live on Google Meets

SPHERE: extreme AO and high-constrat imaging at the VLTc

Seminar by

Dr. Matias Jones F. - European Southern Observatory

Alonso de Córdova 3107, Vitacura, Santiago, Chile

ABSTRACT: In this lecture I will present the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at the VLT.

I will first review the entire instrument, including all four sub-instruments. Then I will describe the main observing and reduction techniques, and the achievable contrast as a function of the angular separation. Finally I will present the main science cases and the main results obtained since the beginning of operations in 2014.

Monday, May 17th, at 16:30

Live on Google Meets

Atmospheres of alien worlds: challenges and opportunities with transmission spectroscopy of extrasolar planets

Seminar by

Dr. Neale Gibson - Trinity College Dublin

The University of Dublin, Ireland

ABSTRACT: Radial velocity and transit surveys have revealed a large and diverse population of exoplanets in our Galaxy, but to truly understand them we need spectra of their atmospheres. Transiting planets allow such measurements via transmission spectroscopy, which has been a very active field of research over the last decade. This technique promises to enable large scale surveys of gas-giant exoplanets, revealing new insights into extreme atmospheric physics and planet formation, as well as the first observations of terrestrial planet atmospheres using next-generation facilities. However, despite substantial improvements in observational techniques and analysis methods, our understanding of exoplanet atmospheres remains limited by our ability to understand and model instrumental systematics in time-series observations. In this talk, I will introduce the main techniques required to probe exoplanet atmospheres, as well as discuss the main limitations and our efforts to circumvent them with advanced statistical modelling, in particular by treating systematics as stochastic processes. In addition I will present some recent results, highlighting the progress and remaining questions in the field.

Wednesday, February 24th, at 15:30

Live on Google Meets

Strange New World

X series of Majorana Lectures organized by the INFN Napoli.

Prof. Joshua Winn - Princeton University, NJ, USA

ABSTRACT: For centuries people wondered whether the stars in the sky harbor

planets of their own. Astronomers began discovering such "exoplanets" in

the 1990s and have identified thousands since then. Advances in technology have brought us to the threshold of finding planets similar to Earth, while also revealing bizarre new worlds unlike anything in our Solar System. I will review our current knowledge of the occurrence and orbital characteristics of planets around other stars -- highlighting

the most remarkable and unexpected exoplanets -- and describe some implications for planet formation theory. I will also present the current results and prospects for future discoveries based on data from an ongoing NASA mission, the Transiting Exoplanet Survey Satellite.

Friday, January 22, at 16:00

Live on Zoom

Recorded video

Galactic habitability revisited

Seminar by

Prof. Amedeo Balbi - Tor Vergata University of Rome

ABSTRACT: I will discuss some recent work on the propensity of the galactic environment to host life, focusing on aspects that were not addressed in earlier studies. In particular, I will focus on i) the habitability of the inner region of the Milky Way ii) the impact of the possible transfer of biological material over interstellar distances. Finally, I will discuss the significance of future detection (or lack thereof) of biosignatures in nearby planetary systems for the distribution of life in the Galaxy.

Wednesday, December 16, at 16:45

Live on Google Meet

Read the Slides