Using the radio telescopes of NRAO and VLA, astronomers have observed the huge flow of gas near the massive star in formation HW2 in Cepheus A. Using the ammonia molecule (NH3), the researchers were able to trace the inward motion of the accretion disk surrounding the star. The accretion rate was found to be 2 · 10 -3 solar masses per year. Simulations made by a member of our group, André Oliva, have modeled the structure of the system and found that a molecular cloud with a steep density profile best reproduces the observed disk size, jet geometry, accretion rate and stellar mass. The image shows a superposition of the simulations and the observations. Known since the 1990s, HW2 had to wait 40 years until the mysteries of its strong mass gain were unravelled.
Link to the research article: https://doi.org/10.1051/0004-6361/202450330
Link to the press release of the Observatory of Geneva: https://www.unige.ch/sciences/astro/en/news/naissance-des-etoiles-massives