Lynden-Bell was born at Dover Castle in Dover, Kent, into a military family,[5] as one of two children to Lachlan Arthur Lynden-Bell (1897–1984) and Monica Rose Thring (1906–1994). His father, a lieutenant colonel, fought on the Western Front and in the Middle East during World War I and had received a Military Cross.[6] He had a sister, Jean Monica, who became a prominent music teacher in Canada.[5][7]
He attended Marlborough College before being admitted to Clare College, Cambridge in 1953.[8] After earning a distinction in the Mathematical Tripos,[8] Lynden-Bell went on to doctoral studies in theoretical astronomy working with Leon Mestel, which he completed in 1960.[9] In 1962, he published research with Olin Eggen and Allan Sandage[10] arguing that the Milky Way originated through the dynamic collapse of a single large gas cloud.[11] In 1969 he published his theory that quasars are powered by massive black holes accreting material. From counting dead quasars, he deduced that most massive galaxies have black holes at their centres.[12]
Lynden-Bell developed a theory for the relaxation of a system of particles in changing potential field known as "violent relaxation." Violent relaxation has many applications in dynamical astronomy, affecting the orbits of stars within star clusters and galaxies.[13] Lynden-Bell is also known for the development of the theory of the gravothermal catastrophe, a phenomenon in star clusters that is the result of the negative heat capacity of gravitational systems. The catastrophe occurs when the core of a cluster shrinks and heats up, causing it to transfer energy to stars in the cluster's halo, leading the cluster core to collapse.[14]
Lynden-Bell authored an influential 1974 paper with James E. Pringle about the evolution of disks around "nebular variables," which were later to become known as T Tauri stars – an early phase in a star's life cycle.[15] The paper predicts the signature of radiation from such disks, which is emitted primarily at infrared wavelengths where it dominates over the emission from the star.[16] Excess infrared emission from young stars has become one of the primary methods used to identify these objects in astronomical surveys.[17]
Lynden-Bell, Roger Griffin, Neville Woolf, and Wallace L. W. Sargent were in the 2015 documentary film Star Men that covered some of their professional accomplishments at their fiftieth reunion to redo a memorable hike.[19]
His research in the last years of his life mainly focused on astrophysical jets and general relativity.[20]
Personal life and death
Donald was married to Ruth Lynden-Bell, a professor of chemistry at the University of Cambridge, on 1 July 1961.[21]
Lynden-Bell died at his home in Cambridge on 6 February 2018, at the age of 82.[2] He had a stroke in the months preceding his death, and never fully recovered.[22] Responding to news of his death, John Zarnecki, then President of the Royal Astronomical Society, praised Lynden-Bell's contributions to astronomy, particularly his "incisive questions at scientific meetings and being generous in his support for others".[23]
^Eggen, O. J.; Lynden-Bell, D.; Sandage, A. R. (1962). "Evidence from the motions of old stars that the Galaxy collapsed". The Astrophysical Journal. 136: 748. Bibcode:1962ApJ...136..748E. doi:10.1086/147433.
