For stars of low and intermediate mass (roughly between 1 and 10 times the mass of the Sun) the late stages of evolution are studied, particularly the AGB (Asymptotic Giant Branch) phase, because their study provides important insights into stellar evolution and the physical processes responsible for the mass loss of the stars and the ionization of the planetary nebulæ.

The astronomers of the A&A group are involved in various projects to study the properties of the dust and the molecules in AGB stars and interstellar matter in general.

They used data of the ESA Herschel satellite, which was launched in May 2009 and operated until April 2013. A major program was the observation program MESS (Mass loss from Evolved Stars) with 300 hours of guaranteed observing time in which different classes of evolved stars were observed: AGB stars to planetary nebulæ, and Wolf-Rayet stars to young supernova remnants.

The observations are completed with data from the ground, e.g. from ALMA, the Atacama Large Millimeter/submillimeter Array of ESO (Chile).

Some of the work that was initiated within the MESS program is now continued within the STARLAB network.