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

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LERMA Detailed Presentation

12 January 2019

LERMA presentation

LERMA (Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres) is a research entity operated by CNRS and 3 higher education institutions: Observatoire de Paris (OP), (...)

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11 January 2019

Management team

Director: Benoi tSEMELIN
benoit.semelin @ obspm.fr
Deputy Director: Martina WIEDNER
martina.wiedner @ obspm.fr
Deputy Director: Ludovic PETITDEMANGE
ludovic.petitdemange @ obspm.fr (...)

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11 January 2019

Administrative team

The administrative team of LERMA is composed of 7 agents who work closely with the administrative services of the CNRS (Ile de France-Meudon delegation (DR5) and INSU), the Paris Observatory (...)

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29 October 2014

Main partners and collaborations

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 (...)

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Séminaires à venir

Vendredi 3 avril 2020, 14h00
Salle de l'atelier, Paris
The great dimming of Betelgeuse in 2019-2020
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
Philippe ANDRE
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