Modelling triple stellar interactions during a pandemic

I study binary stellar astrophysics at Lund University, Sweden. In Birmingham my host, Dr Silvia Toonen, is one of the leading experts in triple and binary stellar evolution. I arrived at my accommodation in the middle of the autumnal Edgbaston Park area next to Birmingham University, and next morning I met my host. She kindly showed me around the campus and introduced me to her colleagues. The image shows me and my host, on one of the top floors in Birmingham University.  We then launched into many science discussions, which continued in the following weeks, together with meetings, work, calculations and more discussions.

If you are reading this post in the mid-2020s, it may (I hope) sound like a regular and nice science visit. However, 2020 was the first year of the COVID-19 outbreak in Europe, and the UK was due to start its second lockdown a few days after I arrived, luckily not affecting universities that much. We have been mostly working remotely from home in Sweden for more than half a year. All the meetings, talks, and conferences have been held digitally over Zoom, and I think I had almost forgotten how it feels to a have a 'real' face-to-face meeting. And while there were plenty of wonderful things to remember the visit by, I think this, then rare, face-to-face experience is something that made the visit special. 

The visit was, of course, also very valuable scientifically. Silvia Toonen had been developing a new triple stellar evolution code called TRES, which allows us to understand what happens to systems of gravitationally-bound triple stars. These systems often produce binary stars in configurations that do not occur in isolated binaries. For example, such binaries may merge or come into contact on eccentric orbits, or even after coming into contact, they may experience continual perturbations by the third companion. Moreover, these situations are common as about every fifth star is a member of a triple system. On the other hand, I had been simulating interacting binaries on supercomputers in a variety of settings, and in particular, had models applicable to eccentric mass transfer in binaries. Triple stellar evolution is a relatively new field. By combining our triple and binary models on the Cirrus II cluster at EPCC in Edinburgh, we discovered several links to observations of stellar systems which are hard to explain in other ways.

The overall experience made me also reflect on the currently-digital format of astronomy collaborations. It is probably fair to say that the pandemic, and the resulting digital connectivity, has made the astronomy community more widely connected. But it is also probably fair to say that, as live interactions became rarer, these connections also became a little bit shallower. The annual European Astronomical Society meeting gathered, digitally, a record 1800 people in 2020, versus about 1200 people in 2019, live. It had been much easier, more natural, and environmentally friendlier, to invite an overseas speaker, digitally, in 2020 than it would have been a year ago. I had been able to present more in 2020 than I would otherwise have been able to manage. But then, a live visit in that digital period clearly showed, at least to me, that live collaborations are different. The discussions end up deeper, more interesting, creative and simply fun. I definitely felt more immersed in the topic. Perhaps there is something about our social nature that makes live interactions feel different.

In summary, I believe 2020 has improved astronomy collaborations in the long run. There are new benefits from digital connectivity, and in the future, the live connectivity will certainly return to coexist with the digital one. As for now, while the pandemic is still here, I am more than grateful for having had that experience. I have not talked much about the many safety aspects such as masks, social distancing, the impossibility of seeing much of the surroundings and relative emptiness of the campus. Nevertheless, with these things in mind, I would definitely recommend live one-on-one science interactions, whenever possible.