Leon Mestel FRS, photographed by Lucinda Douglas-Menzies
I heard this weekend the very sad news that on Friday 15th September 2017, we lost one of our great astrophysicists. Professor Leon Mestel FRS, pictured abvove, passsed away, peacefully in his sleep, at Addenbrooke’s Hospital. He was 90 years old.
Leon Mestel was a scientist of the highest distinction. Elected a Fellow of the Royal Society in 1977, his research interests were very broad, encompassing, but not restricted to, the areas of star formation and structure, especially stellar magnetism and astrophysical magnetohydrodynamics. Among his contributions in other areas were important papers on gravitational collapse and equilibrium in the context of galaxy dynamics, of which the classic `Mestel Disk’ is just one example. He has been awarded both the Eddington Medal (1993) and the Gold Medal (2002) of the Royal Astronomical Society. He had great physical insight which was backed up with prodigious mathematical skill and an encyclopedic knowledge of astrophysics. He also had great powers of concentration and the determination to tackle the kind of extremely challenging problems that scared off lesser intellects. Leon was an ‘old school’ theoretical astrophysicist who was held in very high regard across the astrophysics community, and he will be greatly missed.
Others more expert than me will be able to pay proper tribute to his scientific work, so I’ll restrict myself here to a few personal reminiscences.
Leon Mestel was Professor in the Astronomy Centre at the University of Sussex when I joined it to start my DPhil in 1985. We new postgraduate research research students were required to take four courses on various aspects of astronomy, and pass oral examinations on them, before being allowed to progress beyond the first year. One of these courses was a course on Stellar Structure, taught by Leon Mestel. His lectures were pretty intense – and, I have to say, not made any easier to understand by his truly terrible handwriting on the blackboard! – but I learned a huge amount from them. I still have the lecture notes I took, in fact.
I had a root around in my old files this morning and found this evidence that I once knew something about stars!
All of us found Leon very scary to start with. He was intellectually quite intimidating and seemed to be a rather fierce and irascible character. That opinion changed when, a few weeks into term, he invited us to his house in Lewes for a social evening. We were all a bit nervous on the way there, unsure of what to expect, but as it turns out Leon was a marvellously entertaining and avuncular host. He had a wicked sense of humour and a seemingly inexhaustible stream of jokes, across a spectrum from groan-worthy puns to very risqué stories, including a liberal measure of archetypal Jewish humour. Leon’s father was a Rabbi, actually. That evening broke the ice and we all realised that the was one of the good guys. That he came across as grumpy sometimes was because he was concentrating very hard, but it was rather easy to make him laugh and bring that twinkle to his eye that we will all remember.
His sharp brain and very broad knowledge meant that Leon could spot bullshit at a considerable distance and, while he often seemed to be snoozing through our weekly seminar, he invariably woke up at the end and asked a penetrating question. Since one of his main interests was the role of magnetic fields in astrophysics, a subject that sends many astrophysicists screaming from the room, he would often choose something about magnetism as a question. When I was there his main focus was on the fiendishly difficult problem of building a self-consistent model of the pulsar magnetosphere. He was, however, genuinely interested in all branches of astrophysics and always recognised good work when he saw it, especially from younger scientists.
During my time as a PhD student I had some problems that required me to take quite a lot of time off. Leon was extremely kind and supportive during this period, and he even bent the rules a bit to avoid putting me through the formal process of interrupting my studies. When I was back at work and just about finishing my thesis in 1988 it was Leon who came to see me in person, with a big smile on his face, and offered me a postdoctoral position at Sussex to follow my graduate studies. I nearly fell off my chair with surprise and gratitude.
After I joined the staff later in 1988, it became a bit of a ritual for us to visit the Senior Common Room (which was situated in what is now Bramber House) for lunch, followed by coffee. It turned out that Leon liked to do the Times crossword with his post-lunch coffee. He wasn’t at all averse to a collaborative effort on tricky research problems, and it was thus with crosswords too. We both preferred the Guardian puzzle, actually, but he saved that one for after work and did the Times one because the paper was provided free in the SCR. There was also a Chambers dictionary.
I left Sussex in 1990 and Leon retired in 1992. I didn’t see as much of him after that, except for the occasion when he and my former DPhil supervisor John Barrow organized a meeting in 2004 about Eddington at which I was honoured to be asked to give a talk about the 1919 eclipse expeditions. That was a very nice occasion at which Leon was in sparkling form. Thereafter I saw him occasionally at the RAS Club, but in recent years he didn’t come so often as he found it increasingly difficult to get around.
Leon Mestel was not only a great astrophysicist but also a great character. I’m so very sorry I can’t attend his funeral (which is being held tomorrow), but I send heartfelt condolences to his family, friends and colleagues.
Rest in Peace Leon Mestel FRS (1917-2017)
In the Dark 