LERMA UMR8112

Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères



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Main partners and collaborations

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LERMA develope numerous collaborations both national and international

  • Major agencies and institutions in charge of space missions and major ground-based facilities having collaborations with LERMA : IRAM, ESO, CEA, CNES, ESA, NASA
  • Main collaborating laboratories and institutes : most of Ile-de-France laboratories, in particular members of the 7 “Laboratoires d’Excellence” (LabEx), in which LERMA participates :
    - Plas@Par : Plasma Physics in Paris (UPMC)
    - ESEP : Exploration Spatiale des Environnements Planétaires (Paris Observatory)
    - First-TF : Recherche, Innovation, Formation, Services et Transfert en Temps-Fréquence (CNRS)
    - ICFP : International Center of Fundamental Physics (ENS)
    - ILP : Institut Lagrange de Paris (UPMC)
    - L-IPSL : Labex Institut Pierre Simon Laplace (IPSL)
    - MIChem : Multiscale Interactions in Chemistry (UPMC)

Séminaires à venir

Vendredi 3 avril 2020, 14h00
Salle de l'atelier, Paris
The great dimming of Betelgeuse in 2019-2020
Miguel MONTARGES
KU Leuven, Institute of Astronomy
résumé :
Red supergiant stars are important contributors to the chemical enrichment of the Universe. Together with asymptotic giant branch stars, their lower mass counterpart, they contribute ~ 85% of gas and ~ 35% of dust to the total enrichment of the interstellar medium. Moreover, the stellar wind has a crucial impact on the final mass, hence on the nature of the compact remnant left after the supernova: a 20 solar mass star can loose up to 60% of its mass during its life. Yet the mechanism at the origin of the red supergiant mass loss remains unknown: there is no physical scenario to lift material from the photosphere up to the dust condensation zone where radiative pressure on small grains can drive the wind.

In November-December 2019, the prototypical red supergiant Betelgeuse started an impressive dimming that brought it to 37% of its average optical brightness in February 2020. It is dimmer than this star has been since quantitative magnitude measurements have been recorded (150 years). We have observed Betelgeuse at high angular resolution during this peculiar event with the VLT/SPHERE, VLTI/GRAVITY and VLTI/MATISSE instruments. I will present the first results of this multi-wavelength and multi-technique campaign and bring them in the context of the study of the red supergiant mass loss.
 
Vendredi 17 avril 2020, 14h00
Salle de l'atelier, Paris
Patricia TISSERA
Universidad Andres Bello, Santiago, Chili
 
Vendredi 24 avril 2020, 14h00
Salle de l'atelier, Paris
Tba
Philippe ANDRE
CEA
 
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