Last week (8th-11th October) the workshop "Stellar winds in binary wind-fed systems" took place at IFCA. The aim was to advance towards a unified vision of the physics of stellar winds in massive stars in binary systems. Silvia Martínez Núñez, a postdoctoral researcher at IFCA working at the Athena project, was in charge of organizing this event that brought together 27 experts from various fields of research and had the support of the Vice-Rector for Research and Santander’s City Council.
Silvia is the manager of the Athena Community Office and, during her time devoted to science, she studies the physics of high mass X-ray binary systems. A binary system consists in two astronomical objects so close that they are bound by their gravitational force. In this workshop, the theme focused on systems of two stars orbiting around a common center of masses.
In this interview, Silvia explains the systems she studies, formed by a neutron star and a massive supergiant star. These systems will evolve to one of the scenarios that will end in a gravitational wave event.
Q: What is the meeting about?
A: The purpose of the meeting was to establish new lines of collaboration and synergies between researchers from different fields of stellar astrophysics and to advance in the knowledge of physics that takes place in this type of binary systems. The neutron star is very dense and very small (15 km of diameter), while the supergiant is huge. The supergiant star loses material -by its wind- and falls on the neutron star emitting X-rays. The X-ray radiation gives information about the environment of the compact object, most of the cases a neutron star. The idea is to use that compact object as a probe to study the wind of the massive star.
Q: As a probe?
A: In the end, it is a question of scales. You have to see how the wind changes along the orbit because the neutron star modifies it depending on its orbital position. In addition, ultraviolet and near-infrared radiation give us information about the wind of the massive companion.
Q: How many participants were there in the workshop?
A: There were 27 participants from European universities and one postdoctoral student from Caltech (California Institute of Technology). They are specialists in massive star winds, physics and accretion models, the evolution of binary systems and observational astrophysics of wind-fed systems. There were also 4 people who could not come remotely connected.
Q: What has been the best thing about the workshop?
A: Debate and discussion sessions. Everyone was very motivated and it has been very positive to be able to share ideas from different lines of research that are important in this field of physics. IFCA offers, with its meeting rooms, an environment that favors this type of workshops and promotes the synergies that generate in them.
Q: Which conclusions have you reached?
A: We are always discussing about what we are observing, how we explain these observations and the words we use to describe them. We say there are 3 dictionaries: theoretical/observational, stellar and accretion, and X-ray, ultraviolet and infrared data. It seems like we speak different languages since the same term is used by different fields of study. It's a little confusing. What we do agree on is that discussions are necessary and fun. And, above all, that Santander is a fantastic place to meet. Everyone has enjoyed the city very much and they would like to meet again here in the future.