Seminars and Colloquia at ESO Garching and on the campus

Most stars and planetary systems form in dense and massive star clusters, where the protostellar systems are exposed to strong far-ultraviolet (FUV) radiation originating from nearby massive stars of spectral type O and B. The external photoevaporation process induced by FUV photons dominates the dispersal of planet-forming disks in high mass star forming regions, producing a rapid outside-in loss of gas and dust that can alter the assembling of planets. With the advent of the James Webb Space Telescope (JWST), it is now possible to extend the investigation of the physical and chemical properties of planet-forming environments, particularly of the terrestrial planet-forming region, to massive clusters located at kpc scales. As part of the XUE collaboration, this talk will focus on the unusual findings in the inner regions of a disk surrounding an intermediate-mass star (Herbig), and on the modelling effort of different sources of irradiation to explain the JWST observations of disks in different environments.

The surface brightness fluctuations (SBF) technique is among the most precise distance indicators across a

range from a few to several hundred Mpc. In this informal discussion, I will highlight the key features of the SBF

methodology, focusing on the origin of the SBF signal and its standardization for distance measurements.