DIDIER QUELOZ & MICHEL MAYOR WINNERS OF THE NOBEL PRIZE IN PHYSICS 2019

First of all, congratulations on winning the 2019 Nobel Prize in Physics. For those who don’t know the story already, could you please give us a brief recap of the discovery of 51 Pegasi b? What were your intentions going into the research? How did you feel when you made the discovery?

MM: Yes, it [exoplanet research] was a very hot topic in the last part of the 21st century, but few people were really working on it. It was only a very small number of people working on the domain at the time. Nevertheless, we started with our French colleague from Marseille and Haute-Provence Observatory. We started building a new kind of spectrograph with a much higher sensitivity precision and so on.

We started at the end of the 1980s, and in 1993 or 1994 it was ready to measure. And we asked for observing time, because it was not automatic. We got about one week every two months to measure solar-type star selection – 142 stars – and we were very surprised that we got the first hint of an exoplanet at the end of 1994. This was actually a big surprise, because the theory at the time for the formation of giant planets – like Jupiter and so on – was its period should be larger than ten years. It was not a small discrepancy because 51 Peg’s orbit is only four days. It was a discrepancy by a factor of a thousand.

I decided to postpone the announcement for the next season. In July 1995, with Didier, we started to remeasure the same star to check if the period was present with exactly the same period, with the same amplitude and the same traits. This was a check to eliminate any uncertainty.

We then decided to publish the paper in Nature at the end of August, and then there is the review procedure. It was potentially a hot topic, and so Nature asked