Periodic Reporting for period 1 - StarlightWinds (Mass loss in the lives and deaths of massive stars)
Okres sprawozdawczy: 2015-07-01 do 2017-06-30
The overarching goal of this ambitious project has been to fundamentally improve this situation by using novel methods to develop new models of radiation-driven winds from hot, massive stars. Using state-of-the art numerical techniques, as well as innovative analytic theory development, for the effects of light-transfer on the wind-dynamics, we have developed a new generation of drastically improved wind models from massive stars in their hydrogen core burning phase. Including critical physics ingredients lacking in earlier generations of such simulations, our new models show systematically lower mass-loss rates when compared to these earlier models, which are the current standard predictions included in calculations of the star's evolution. First results from a few observationally driven studies seem further to empirically support our lower predicted mass-loss rates, and tentative studies reducing the mass-loss rates in evolution calculations indicate significant effects on e.g. the evolution of the star's surface rotation. Spurred by this, the former fellow and his old and new collaborators are now planning several exciting spin-off scientific projects, which will build directly on the results obtained during the Marie-Curie action.
Prof. Sundqvist and his former group at CAB are still working closely together, though, and several peer-reviewed research articles with the former fellow as co-author have also already been published (6 such papers in which the current Marie-Curie project 656725 has been acknowledged have already appeared in the literature, and several more are underway, see further below). Moreover, several beneficial synergy effects and collaborations have been initiated, as the fellow has actively participated in the various activities in the research-group led by previous project supervisor Dr. F. Najarro at CAB in Madrid. For example, at the present Dr. Najarro's PhD student M. Rubio is conducting the final parts of her thesis (expected to be finished summer 2017), and Prof. Sundqvist has since his first arrival to Madrid been highly involved in Ms. Rubio's work; as such, he gained plenty of invaluable experience as mentor and co-supervisor during his time in Madrid, preparing him very well for his current teaching and supervising duties as professor at KU Leuven.
More specifically, during our time at CAB we have delivered a new, significantly improved generation of radiation-hydrodynamic, steady-state wind simulations of hot star wind. These models now include two critical physics components neglected in earlier generations, and first results of them indeed show systematically lower mass-loss rates compared to the current standard predictions included in stellar evolution calculations. First observational results carried out by M. Rubio at CAB, together with former fellow Sundqvist and supervisor Najarro, seem to support such general reduction of mass-loss rates. A cornerstone-paper about these findings is currently being written (led by Sundqvist, in close collaboration with former project-supervisor F. Najarro at CAB), and will be submitted to a peer-review journal shortly. Simultaneously, PhD candidate Rubio leads the writing-up of the corresponding empirical results. What is already clear though, is that these mass-loss rate reductions potentially will have quite dramatic consequences for both massive-star evolution models and the many other astronomical applications that rely on a firm understanding of the lives and deaths of such massive stars."