Donald D. Clayton

Career

A historic connection of Clayton's academic career to NASA's Apollo Program arose through establishment by Rice University of its Department of Space Science in 1963. This action by Rice University provided the academic position assumed by Clayton in 1963. Clayton described this good fortune in his autobiography. His academic research into five fields of astrophysics championed by him is detailed in section 5 below. Foundational academic positions at Caltech, Rice University and Clemson University were augmented by international breadth: seven-year-long academic affiliations in Cambridge (1967–1974) and later in Heidelberg (1976–82), as well as by visiting summer positions in Cardiff UK (1976, 1977) as well as sabbatical leaves in Cambridge (1971), Heidelberg (1981) and Durham University UK (1987).

Following his two-year (1961–63) postdoctoral research fellowship at Caltech, Clayton was awarded an Assistant Professorship, one of the four founding faculty members in Rice University's newly created Department of Space Science (later renamed Space Physics and Astronomy). There he initiated a graduate-student course explaining nuclear reactions in stars as the mechanism for the creation of the atoms of our chemical elements. His pioneering textbook based on that course (Principles of Stellar Evolution and Nucleosynthesis, McGraw-Hill 1968) earned ongoing praise. In 2018, 50 years after its first publication, it is still in common usage in graduate education throughout the world. At Rice Clayton was awarded the newly endowed Andrew Hays Buchanan Professorship of Astrophysics in 1968 and held that endowed professorship for twenty years until responding to the opportunity to guide a new astrophysics program at Clemson University in 1989. During the 1970s at Rice University Clayton guided Ph.D. theses of many research students who achieved renown, especially Stanford E. Woosley, William Michael Howard, H. C. Goldwire, Richard A. Ward, Michael J. Newman, Eliahu Dwek, Mark Leising and Kurt Liffman. Senior thesis students at Rice University included Bradley S. Meyer and Lucy Ziurys, both of whom forged distinguished careers in the subjects of those senior theses. Historical photos of several students can be seen on Clayton' s photo archive for the history of nuclear astrophysics. Clayton followed the historic Apollo 11 mission while on holiday with his family in Ireland while traveling to Cambridge UK for his third research summer there.

Letters in winter 1966 from W.A. Fowler unexpectedly invited Clayton to return to Caltech in order to coauthor a book on nucleosynthesis with Fowler and Fred Hoyle. In his autobiography Clayton quotes these letters. He accepted that offer but the book was never written because while he was resident at Caltech Clayton was invited by Fred Hoyle to Cambridge University (UK) in spring 1967 to advise a research program in nucleosynthesis at Hoyle's newly created Institute of Astronomy. The award to Clayton of an Alfred P. Sloan Foundation Fellowship (1966–68) facilitated leaves of absence from Rice University for this purpose. Clayton exerted that research leadership in Cambridge during 1967-72 by bringing his research students from Rice University with him. That prolific period ended abruptly by Hoyle's unexpected resignation from Cambridge University in 1972. Clayton was during these years a Visiting Fellow of Clare Hall. At Rice University W.D. Arnett, S.E. Woosley, and W.M. Howard published jointly numerous innovative studies with Clayton on the topic of explosive supernova nucleosynthesis. During his Cambridge years, Clayton proposed radioactive gamma-ray-emitting nuclei as nucleosynthesis sources for the field of gamma-ray astronomy of line transitions from radioactive nuclei with coauthors (Stirling Colgate, Gerald J. Fishman, and Joseph Silk). Detection of these gamma-ray lines two decades later provided the decisive proof that iron had been synthesized explosively in supernovae in the form of radioactive nickel isotopes rather than as iron itself, which Fowler and Hoyle had both advocated.

During (1977–84) Clayton resided part-time annually at the Max Planck Institute for Nuclear Physics in Heidelberg as Humboldt Prize awardee, sponsored by Till Kirsten. Annual academic leaves from Rice University facilitated this. There he joined the Meteoritical Society seeking audience for his newly published theoretical picture of a new type of isotopic astronomy based on the relative abundances of the isotopes of the chemical elements within interstellar dust grains. He hoped that such interstellar grains could be discovered within meteorites; and he also advanced a related theory that he called cosmic chemical memory by which the effects of stardust can be measured in meteoritic minerals even if stardust itself no longer exists there. Clayton designated the crystalline component of interstellar dust that had condensed thermally from hot and cooling stellar gases by a new scientific name, stardust. Stardust became an important component of cosmic dust. Clayton has described the stiff resistance encountered from meteoriticist referees of his early papers advancing this new theory. He nonetheless established that research program at Rice University, where he continued guiding graduate-student research on that topic. He and student Kurt Liffman computed a pathbreaking history of survival rates of refractory stardust in the interstellar medium after its ejection from stars; and with student Mark D. Leising computed a propagation model of positron annihilation lines within nova explosions and of the angular distribution of gamma ray lines from radioactive ²⁶Al in the galaxy. Following laboratory discovery in 1987 of meteoritic stardust bearing unequivocal isotopic markers of stars, Clayton was awarded the 1991 Leonard Medal, the highest honor of the Meteoritical Society. Feeling vindicated, Clayton exulted in Nature "the human race holds solid samples of supernovae in its hands and studies them in terrestrial laboratories".

In 1989 Clayton accepted a professorship at Clemson University to develop a graduate research program in astrophysics there. He began this academic segment (1989–present) by hiring three talented young astrophysicists to vitalize joint research with the Compton Gamma Ray Observatory (launched in 1991 after several delays). Its four instruments successfully detected gamma-ray lines identifying several of the radioactive nuclei that Clayton had predicted to be present in supernova remnants. Clayton had been designated ten years earlier co-investigator on the NASA proposal submitted by James Kurfess for the Oriented Scintillation Spectrometer Experiment OSSE, one of the four successful instruments carried into orbit by Space Shuttle Atlantis, and he carried that research contract to Clemson. Simultaneously Clayton developed at Clemson his stardust research, introducing annual workshops for its researchers. The initial NASA-sponsored workshop at Clemson in 1990 was so lively that it was repeated the following year jointly with Washington University in St. Louis cosponsorship, and in later years cosponsored also by the University of Chicago and by the Carnegie Institution of Washington. These workshops featured the excitement of new isotopic discoveries, and also helped participants focus their ideas for submission of abstracts to NASA's Lunar and Planetary Science Conference. Otherwise participants' workshop discussions were not shared or publicized.

Eventually a unique new goal became to assemble from his large personal collection of photographs a web-based archive for the history of nuclear astrophysics and to donate the original photographs to the Center for the History of Physics, a wing of the American Institute of Physics. The thrusts of Clayton's career at Clemson University are well represented on that Photo Archive by photos between 1990 and 2014. Following his retirement from academic duties in 2007, Clayton remained quite active in research problems involving condensation of dust within supernovae and has also published a scientific autobiography, Catch a Falling Star. Clayton's published refereed research papers prior to 2011 are listed at http://claytonstarcatcher.com/files/documents/JournalPub.pdf

Personal life

Clayton married three times: in 1954 in Dallas to Mary Lou Keesee (deceased 1981, Houston) while they were students at SMU; in 1972 in St. Blasien, Germany to Annette Hildebrand (divorced 1981, Houston); and in 1983 in the Rice University Chapel, to the former Nancy Eileen McBride an artist. His children with Mary Lou were Donald Jr and Devon (deceased); with Annette was Alia Fisher; and with Nancy was Andrew.

Clayton resided with Nancy in historic G. W. Gignilliat House (1898) in Seneca, South Carolina. Clayton's mother and father had both been born on family farms in Fontanelle IA to parents who had lived their entire lives on Fontanelle farms. Their own parents had immigrated to Iowa near 1850 from England and Germany. Two of Clayton's great grandfathers (Kembery and Clayton) fought in the Civil War (North). Robert M. Clayton fought in Sherman's Army at the battle of Atlanta.

While at Rice University, Clayton was introduced by patron of the arts Dominique de Menil to Italian filmmaker Roberto Rossellini, and they jointly conceived of a film about one scientist's deepening realizations during a cosmological life, a sequence of experiences which Clayton proposed to provide for that project. In summer 1970 Clayton spent two weeks in Rome working daily with Rossellini on that effort, which failed owing to insufficient financial support or to insufficiently theatrical plan. Clayton's published early memoir The Dark Night Sky: a personal adventure in cosmology laid out his plan for that film.