Capturing the birth of new stars
Proplyds are thought to be young planetary systems in the making. As newborn stars emerge from the gas and dust of star-forming regions in the heart of the Orion Nebula, discs form around them. While spinning discs generate heat to become a new star, remnants around the far reaches of the disc attract clumps of dust that will be transformed into new planets.The European Southern Observatory's (ESO) Very Large Telescope (VLT), with its high sensitivity and resolution, has taken detailed pictures of circumstellar discs. By studying these silhouetted discs, astronomers working on the 'Protoplanetary disks in regions of massive star formation: Coupling advanced observations to models' (3DPROPLYDS) project were able to determine the chemical properties of dust grains brought together. Researchers focused on two different discs around young and forming stars within the gaseous folds of the Orion Nebula. Named LV2 and HST-10, these discs represent two of the largest proplyds. Integral field spectroscopy (IFS) allowed them to overcome the limitations of long slit spectroscopy by simultaneously providing a spectrum for every element in the field of view. Researchers compared the chemical composition of the embryonic planetary system with that of region where stars are generated in the Orion Nebula and the composition of the nebula itself as this can be estimated by samples taken at different points within it. This analysis gave new insights into discrepancies found between the abundances of ions of carbon, nitrogen, oxygen and heavier species, a long-standing problem. The high-density clumps were found to play a crucial role in the production of discrepancies when determining these from the analysis of interstellar clouds composed of atomic hydrogen. 3DPROPLYDS successfully exploited high-resolution imaging of the morphology of protoplanetary discs to generate new knowledge. Future investigations based on a larger-scale IFS mosaic of the Orion Nebula will be valuable for exploring how small-scale structures have an impact at larger scales. Through its significant investment in ESO and the funding of such projects, Europe is keeping its competitive edge in astronomy.
Keywords
Stars, Orion Nebula, proplyd, planetary system, Very Large Telescope, spectroscopy, chemical composition