Martina Wiedner – The Far-Infrared Spectroscopy Space Telescope (FIRSST) mission proposal @ B18N, Salle Univers
Mai 7 @ 11 h 00 min – 12 h 30 min

Titre: The Far-Infrared Spectroscopy Space Telescope (FIRSST) mission proposal

Par : Martina Wiedner


After the Herschel satellite, ISO and a generation of smaller satellites as well as the grounding of the SOFIA airplane observatory the far-IR sky is currently hidden from our view, with the exception of occasional short glimpses by balloon missions. NASA has therefore published a call for a far-IR (or X-ray) mission to be launched around 2032. Five X-ray proposals and three far-IR proposals, PRIMA, SALTUS and FIRSST have been submitted to NASA last November. In the talk I will present the FIRSST mission its science goals, the satellite and its instruments, in particular the heterodyne receiver. FIRSST aims to identify the physical processes that form super-Earth and mini-Neptune sized planets, traces the flow of water from star-forming cores to rocky planets and pierce the dusty shrouds to witness galaxy growth. FIRSST has a 1.8m cryogenically cooled primary mirror and is equipped with two instruments: a US direct detection spectroscopy instrument (DDSI) and a mostly European heterodyne spectroscopy instrument (HSI), which we have designed within an international consortium.

Séminaire Thalès @ B18N, Salle Univers
Mai 21 @ 11 h 00 min – 12 h 30 min

Titre: Thales, activités spatiales & ingénierie scientifique

Par : M. Marseille & L. Mercuri


Après une introduction des activités spatiales de Thales (observations de la Terre et de l’Univers), notamment des multiples mission scientifiques spatiales CNES sur lesquelles nous contribuons, nous présenterons ce qui est réalisé en termes d’ingéniérie logicielle scientifique au sein de notre département « Augmented Data » de Toulouse, les méthodologies employées, et ce que nous qualifions de bonnes pratiques logicielles. L’IA sera aussi abordée, tant sur son développement que son industrialisation. Enfin, nous vous exposerons les perspectives de carrière et d’évolution au sein de notre groupe, sur des profils proches de vos activités scientifiques. Nous aborderons également nos processus de recrutements, en particulier les attendus pour les candidats qui souhaiteraient se tourner vers notre groupe.

Ce séminaire sera suivi d’une discussion ouverte à tous à 14H00.

Slawa Kabanovic – Highlights of the SOFIA Legacy Program FEEDBACK and Future Perspectives on Orion A @ B18N, Salle Univers
Mai 24 @ 11 h 00 min – 12 h 30 min

Titre: Highlights of the SOFIA Legacy Program FEEDBACK and Future Perspectives on Orion A

Par : Slawa Kabanovic (U. Cologne)


During the FEEDBACK legacy survey, 11 high-mass star-forming regions were observed using the [CII] 158 and [OI] 63 micron lines with the upGREAT receiver on SOFIA. We here present the scientific highlights of the program and give a status report on our ongoing work in Orion A.

One significant focus of FEEDBACK was the exploration of galactic HII region bubbles. Expanding [CII] shells were identified in all sources, and potential driving mechanisms were assessed. Our findings indicate that, in the majority of cases (e.g. RCW120, RCW36, NGC7538), the high-velocity expansion is attributed to the stellar wind from massive stars. Recently, we uncovered signs of cloud destruction due to stellar winds and radiation, quantifying this phenomenon using [CII] in the RCW79 region.

Utilizing a multi-layer radiative transfer model for CO and [CII] emission, coupled with HI self-absorption (HISA) studies, we investigated the RCW 120 bubble. Our study detected significant amounts of cold C+ linked to an extensive HI envelope and revealed that the related molecular cloud exhibits a flattened structure likely originating from a residual filament.

In Cygnus X, we unveiled the highly dynamic interaction of CO-dark gas in the form of atomic flows with a small molecular fraction), using [CII], CO emission and HISA. The cloud formation timescale is only ~1 Myr, consistent with recent simulations of fast, colliding HI flows.

As part of the Orion Legacy project (PI S. Kabanovic), multiple long-time integrations across Orion A were performed, successfully detecting weak [13CII] transition lines. These observations enable the first determination of the local [12CII]/[13CII] abundance ratio and possible fractionation effects directly in different physical conditions in Orion A, such as NGC 1977, M43, and M42.

Gaspard Duchêne – On the demographics and structure of protoplanetary disks @ B18N, Salle Univers
Mai 29 @ 11 h 00 min – 12 h 30 min

Titre: On the demographics and structure of protoplanetary disks

Par : Gaspard Duchêne (IPAG)

Abstract: Protoplanetary disks represent the birth environment of the mature exoplanets now known by the thousands. Over the past decade, several major instrumentation breakthroughs (such as HST, « extreme » adaptive optics, ALMA and now JWST) have led to a slew of high-resolution observations that shed crucial light on the structure of these disks and on the processes at play in forming these planets. In this talk, I will illustrate how a unique observing point of view, when disks are seen almost exactly edge-on, provides both a much less biased view of the demographics of protoplanetary disks, and a unique opportunity to probe their radial and vertical structure. In particular, I will demonstrate how we have used high-resolution observations to quantify the degree of settling of planet-forming pebbles and smaller dust grains, to directly image photoevaporative winds emanating from the surface of some disks, and to find suggestive evidence for the presence of dust-entraining winds far above the disk surface.

Anthony Berdeu – Data reduction and inverse problem approaches – An efficient (and cheap) way to push the instrumental limits @ B18N, Salle Univers
Juin 14 @ 11 h 00 min – 12 h 30 min

Titre: Data reduction and inverse problem approaches – An efficient (and cheap) way to push the instrumental limits

Par : Anthony Berdeu, LESIA / Observatoire de Paris – PSL

Abstract: Study of astrophysical objects requires always more complex models (black hole surrounding, exoplanet atmosphere, accretion disk, galaxy formation and evolution, …) whose inputs imply always more precise measurements. On the other side, the astronomical instruments start to reach their fundamental limits (negligible sensor readout noise, precise mirror polishing, technologies harder to scale up to extremely large telescopes, …). During my talk, I will discuss how data science applied for optimal data reduction and processing via inverse problem approaches can bridge this gap, by pushing the experimental limits without the need of further instrumental developments. I will introduce different applications of my research: integral field spectroscopy (SPHERE/IFS), blind deconvolution and PSF reconstruction (SPHERE/ZIMPOL) and extreme adaptative optics (GRAVITY+).

Julien Drevon – Study of the dust formation process around evolved stars with the VLTI/MATISSE instrument @ B18N, Salle Univers
Juin 18 @ 11 h 00 min – 12 h 30 min

Titre: Study of the dust formation process around evolved stars with the VLTI/MATISSE instrument
Étude de la formation de poussières autour des étoiles évoluées avec l’instrument VLTI/MATISSE

Par : Julien Drevon (ESO)


Version EN :
With the advent of optical interferometry and the construction of increasingly efficient interferometric instruments, our view of the environments of evolved stars in the last decades has been considerably modified. We know today that evolved stars are the main dust and heavy elements factories in the Universe. Without evolved stars, the materials necessary for the formation of asteroids, planets, and everything around us on Earth, including life itself based on carbon, would not exist. Thus, understanding how these elements are formed around evolved stars, how the stellar wind and the so-called mass-loss process spread those elements in the universe, is also to some extent understanding our own origin, in other words, “we are all stardust”. Currently one of the big questions of the field is to what extent each type of evolved stars enriches the interstellar medium? This question remains because of our misunderstanding of the process of dust formation and mass loss around evolved stars.
I will summarize my work on two evolved stars: the first one is an AGB, i.e low mass carbon-rich star called R Sculptoris, and the other, a red supergiant Oxygen-rich star called Betelgeuse. The purpose of my work is to spatially resolve where the dust and molecules around evolved stars are formed, and to reconstruct their environments using interferometric observations. My aim is to provide strong spatial and spectral constraints to better understand the dust formation process and the conditions for the formation of stellar winds. While showing how my work helps to address today’s issues, I will also highlight future’s issues and the different methods to address them.

Version FR:
Avec l’avènement de l’interférométrie optique et la construction d’instruments interférométriques de plus en plus efficaces, notre vision de l’environnement des étoiles évoluées au cours des dernières décennies a été considérablement modifiée. Nous savons aujourd’hui que les étoiles évoluées sont les principales usines de poussières et d’éléments lourds de l’Univers. Sans étoiles évoluées, les matériaux nécessaires à la formation des astéroïdes, des planètes et de tout ce qui nous entoure sur Terre, y compris la vie elle-même basée sur le carbone, n’existeraient pas. Ainsi, comprendre comment ces éléments se forment autour des étoiles évoluées, comment le vent stellaire et le processus dit de perte de masse propagent ces éléments dans l’univers, c’est aussi, dans une certaine mesure, comprendre notre propre origine, en d’autres termes, « nous sommes tous des poussières d’étoiles. » Actuellement l’une des grandes questions que l’on se pose est de savoir dans quelle mesure chaque type d’étoiles évoluées enrichit le milieu interstellaire ? Cette question subsiste en grande partie à cause de notre compréhension incomplète du processus de formation de poussière et de perte de masse autour des étoiles évoluées.
Je résumerai mes travaux sur deux étoiles évoluées : la première est une AGB, une étoile de faible masse riche en carbone appelée R Sculptoris, et l’autre, une étoile supergéante rouge riche en oxygène appelée Bételgeuse. Le but de mon travail est de déterminer spatialement où se forment les poussières et les molécules autour des étoiles évoluées, et de reconstruire leurs environnements à l’aide d’observations interférométriques. Mon objectif est de fournir des contraintes spatiales et spectrales fortes pour mieux comprendre le processus de formation des poussières et les conditions de formation des vents stellaires. Tout en montrant comment mon travail contribue à résoudre les problèmes d’aujourd’hui, je mettrai également en lumière les problématiques de demain et comment y faire face.