DE KOTER , A.

The processes by which red supergiants lose mass are not fully understood thus-far and their mass-loss rates lack theoretical constraints. The ambient surroundings of the nearby M0.5 Iab star Antares offer an ideal environment to obtain detailed empirical information on the outflow properties at its onset, and hence indirectly, on the mode(s)...

We present observations of the famous OH/IR star OH 26.5+0.6 obtained using the Mid-Infrared Interferometric Instrument MIDI at the European Southern Observatory (ESO) Very Large Telescope Interferometer VLTI. Emission of the dusty envelope, spectrally dispersed at a resolution of 30 from 8 μm to 13.5 μm, appears resolved by a single dish UT...

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Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates1, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates2.) Little...

Context. The 'Great Dimming' of the prototypical red supergiant Betelgeuse, which occurred between December 2019 and April 2020, gives us unprecedented insight into the processes occurring on the stellar surface and in the inner wind of this type of star. In particular it may bring further understanding of their dust nucleation and mass-loss...

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Context. S-type asymptotic giant branch (AGB) stars are thought to be intermediates in the evolution of oxygen- to carbon-rich AGB stars. The chemical compositions of their circumstellar envelopes are also intermediate but have not been studied in as much detail as their carbon- and oxygen-rich counterparts. W Aql is a nearby S-type star, with...

From November 2019 to April 2020, the prototypical red supergiant Betelgeuse experienced an unexpected and historic dimming. This event was observed worldwide by astrophysicists, and also by the general public with the naked eye. We present here the results of our observing campaign with ESO's VLT and VLTI in the visible and infrared domains....

This overview paper presents ATOMIUM, a Large Programme in Cycle 6 with the Atacama Large Millimeter/submillimeter Array (ALMA). The goal of ATOMIUM is to understand the dynamics and the gas phase and dust formation chemistry in the winds of evolved asymptotic giant branch (AGB) and red supergiant (RSG) stars. A more general aim is to identify...

Abstract From Nov. 2019 to May 2020, the red supergiant star Betelgeuse experienced an unprecedented drop of brightness in the visible domain called the great dimming event. Large atmospheric dust clouds and large photospheric convective features are suspected to be responsible for it. To better understand the dimming event, we used...