Letters of Intent received in 2018

LoI 2020-2028
Massive Stars Near & Far

Topics

- Recent observations and surveys of massive stars at different evolutionary states

- Massive star evolution: theoretical modelling of single and binary stars

- Physical processes in massive stars: e.g. mass loss, mixing, rotation, pulsation, and magnetic fields

- Supernovae, gravitational wave events, and other endpoints of massive stars

- Feedback from massive stars, both in the local and the early Universe

- Massive star populations across cosmic time, and the feedback on their host galaxies

- Properties of very massive stars, the upper-mass limit, and supermassive stars in the early Universe

- Population III stars: formation, evolution, and possibility of pair-instability supernovae

Rationale

Research on massive stars has been greatly enriched in recent years by the latest surveys of the Magellanic Clouds and other local group galaxies, and results from the Gaia mission now enable new studies on Galactic stars as a population. Furthermore, the detection of gravitational waves from merging black holes and neutron stars opens up a new window on stellar evolution. Despite great advances over the past few years, it is clear that we require a better framework for understanding how massive stars evolve in isolation, in binary systems, and their eventual mergers. This requires improved knowledge on how physical processes vary as a function of metallicity, from roughly Galactic metallicity in the solar neighbourhood towards much lower values more characteristic of the early Universe.

Given the recent advancements in massive star research outlined above, we believe this is an optimal time to bring together the observational and theoretical communities in an IAU Symposium (which we typically have every 4 years). We propose to host the meeting in Ireland in 2020, following the success of New Zealand in 2016 (IAUS 329), where we brought together a large number of researchers working in the fields of both massive stars and supernovae. For the 2020 meeting we wish to bring 'the early Universe' into the equation as a special topic.

In the years following the 2020 meeting, when the light from the first galaxies is expected to be uncovered with JWST and E-ELT, we will require a better understanding of the properties and evolution of massive stars at very low metallicity. Recent observations of Quasars at high redshift seem to favour the existence of supermassive stars (of order 100,000 times the mass of our Sun) in the early Universe, but no-one knows if these stars may even form, nor how they would evolve and die. We hope that by bringing the massive star researchers in contact with the early Universe community, such questions with far reaching implications can start to be addressed.

The location of Ireland is very appropriate given the large increase in Irish researchers working in the area of massive stars. At a time when Ireland has just recently joined ESO, the time & place for this meeting could not be more ideal. Moreover, Ireland has been very successful in setting up dark-sky parks such as the Mayo International Dark Sky Park, increasingly being used for outreach, education, and tourism. We will engage with amateur astronomy partners to incorporate citizen science and outreach as part of the meeting programme. Over the next couple of weeks we are planning to form a geographically balanced & diverse SOC to optimise the input from the relevant communities.