Determining the late phase of stellar evolution (astronomy)

Stars in the late evolutional phase synthesise elements, and expel them into the interstellar medium (ISM), thus, these stars are thought to be the key for the chemical enrichment of the ISM of galaxies. Yet, there is no well-established picture of how these stars lose material from their stellar surface, and how much they lose to the ISM. The Herschel Space Observatory, launched in 2009, has taken spectra of
over 50 evolved stars in the Milky Way. Herschel gave the first real opportunity to explore spectra ranging between 190-650 microns. By
analysing the numerous molecular lines detected in these spectra, the PhD student is expected to identify the properties of stellar winds, to quantify the mass loss from these stars, and to unveil the driving mechanism of stellar winds.
The project will further extend to more distant stars in the Local Group of Galaxies, in the event of the James Web Space Telescope (JWST) being launched in 2018. State of art telescopes and instruments give a new window to investigate the stellar evolution and thus the chemical evolution of galaxies.