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In Memoriam

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Robert N. Clayton (1930-2017)

Bob Clayton passed away on Dec. 30, 2017, after several years of declining health at his home in Michigan City, Indiana, surrounded by family. Bob was the Meteoritical Society’s 1982 Leonard Medalist. He was born on March 20, 1930, in Hamilton, Ontario, Canada. He received his B.S. and M.S. degrees from Queen’s University, Ontario, and his Ph.D. from Caltech (1955) mentored by Samuel Epstein. He joined the Chemistry Department and the Enrico Fermi Institute (1958), and then the newly founded Department of Geophysical Sciences (1961) at The University of Chicago. He was the Enrico Fermi Distinguished Service Professor until he retired in 2001, remaining active in emeritus status until about 2014.

Bob joined the cosmochemistry community during the Apollo program in the late 1960’s, where he started measuring oxygen isotopes (δ18O) in ordinary chondrites. He is best known for his discovery of oxygen isotope variability in calcium-, aluminum-rich inclusions (CAIs) with the classic 1973 paper that launched a new stage of his career. Bob’s superb three-isotope oxygen isotopic analyses so dominated the field that he established isotopic classification of solar system materials and analyzed every new meteorite for 25 years with no competition, all with a late-1950s mass spectrometer equipped with a chart recorder, a ruler, and a pocket calculator. He developed O, N and Si isotope studies of lunar samples and meteorites by gas source mass spectrometry with Toshiko Mayeda, his long-term research associate from 1958 to 2004, Richard Becker, Mark Thiemens, and many other students and postdocs. His studies (with Typhoon Lee and Gerry Wasserburg) led to the recognition of Fractionated, Unknown Nuclear (FUN) isotopic anomalies in CAIs. He pioneered SIMS techniques beginning (1977) with in situ Al-Mg systematics of CAIs and chondrules with Ian Hutcheon, Richard Hinton and Andy Davis. Bob initiated an effort to develop Resonance Ionization Mass Spectrometry for cosmochemistry with Michael Pellin and Andy Davis that led to the isotopic analysis of individual presolar SiC grains for Ba, Sr, Ru, Fe, etc., launching a new form of laboratory-based nuclear astrophysics. Post-retirement, Bob’s note on self-shielding (2002) marked a major departure from his previous thinking on a variety of topics: he realized that the Genesis mission could yield a key piece of the solar system’s oxygen puzzle, and initiated the debate on the role of photochemical effects in producing the solar system oxygen isotope variability that still continues.

Bob will be remembered as a generous collaborator who worked selflessly with most of the major teams in meteorite research. He produced over 23 PhD students and 22 postdoctoral fellows in a career that spanned over five decades, during the last four of which he was heavily involved in meteoritics. Clayton’s morning coffee group in his Enrico Fermi Institute laboratory was a famous gathering place throughout his long career at The University of Chicago. His contributions were recognized widely including with the Goldschmidt Medal (Geochemical Society, 1981), the Bowie Medal (American Geophysical Union, 1987), the Urey Medal (European Association of Geochemistry, 1995), and the National Medal of Science (2004), in addition to the Leonard Medal. He was a Fellow of the Royal Society of London, and of the Royal Society of Canada, and a Member of the US National Academy of Sciences.

Bob Clayton is survived by his wife, Cathy, his daughter, Elizabeth, and his granddaughter, Leonora.
12:13 | Obituary

In Memoriam

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Elmar K. Jessberger (1943–2017)

Elmar K. Jessberger passed away on November 29, 2017, at the age of 74. Elmar was a Fellow of The Meteoritical Society since 1994 and chairman of the Leonard Medal Committee from 2001 to 2002. He was organizer of the Society’s 66th annual meeting 2003 in Münster. Main belt asteroid 16231 Jessberger, discovered in 2000, was named after him in 2005.

Elmar received his PhD from Heidelberg University in 1971 with a thesis on mass spectrometric analysis of trapped gases in lunar material, meteorites, and terrestrial basalts. This study was performed with Josef Zähringer and Till Kirsten at the Max Planck Institute for Nuclear Physics in Heidelberg, where Elmar had started working as an undergraduate in 1968 and where he stayed, ultimately as a senior scientist, until 1996. During that time, he received an NSF fellowship and worked from 1972 to 1973 with Jerry Wasserburg at Caltech. As a guest scientist, Elmar visited the State University of New York in Stony Brook in 1981 and the McDonnell Center for the Space Sciences, Washington University in Saint Louis in 1984. From 1991 to 1992, he spent a sabbatical at the University of Vienna and the Natural History Museum in Vienna.

Most of Elmar’s early work was related to 40Ar-39Ar dating of lunar rocks, meteorites, and terrestrial impact crater material. Later, he started working on interplanetary dust particles using proton-induced X-ray spectroscopy (PIXE). In 1986, after the flyby of the Vega 1 & 2 and the Giotto space probes at comet 1P/Halley, Elmar got heavily involved in the evaluation and interpretation of the data from the impact-ionization mass spectrometers onboard those missions. During his involvement in further space experiments, which ultimately led to the COSIMA instrument for the European Rosetta mission to comet 67P/Churyumov-Gerasimenko, he promoted establishing time-of-flight secondary ion mass spectrometry (TOF-SIMS) as a new technique in cosmochemistry. His credo always was that sample analysis in space has to be complemented by state-of-the-art laboratory analysis here on earth.

In 1996, Elmar became full professor of Analytical and Experimental Planetology at the Institute for Planetology at the University of Münster. During his time in Münster, he established a dedicated TOF-SIMS laboratory, which played an important role in the analysis of cometary samples returned by the Stardust mission. He was one of the initiators of the Mercury Radiometer and Thermal Infrared Spectrometer (MERTIS) for the BepiColombo mission and promoted GENTNER, a combined laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy instrument, for the ExoMars mission.

After his retirement in 2008, Elmar stayed involved in science, mainly as an advisor in some of the projects he initiated. He was especially pleased to see his scientific legacy live on in the work of his numerous former students. Elmar constantly promoted the careers of his students and enabled them to become successful scientists.

We, who had the privilege to work closely with Elmar, will miss him as a great mentor and very good friend. We will especially miss the endless discussions, which usually involved a lot of cigarette smoke and a glass of wine (or two), about science, life, and everything.

Towards the end of his fulfilled life, Elmar became a devoted family man, who took the greatest pleasure in spending time with his five grandchildren Jonathan, Luise, Lotte, Stella, and Jil. Elmar is survived by his wife Ulrike, their sons Florian and Sebastian, and their families.

Thomas Stephan and Mario Trieloff
17:45 | Obituary

Two-part article by Richard Norton

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Two-part article by Richard Norton, “Personal Recollections of Frederick C. Leonard"

Part 1

Part 2
17:38 | People

In Memoriam

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Gerald Rowland (1928-2017)

Gerald Rowland passed away on September 19, 2017 at the age of 89.  He was born August 13, 1928 in Whittier, California, and he attended the University of California, Los Angeles receiving a B.S. in mathematics in 1950.  In order to meet the requirements of his undergraduate teaching minor he needed an upper division science course, and he took a course in astronomy from Frederick C. Leonard, my father.  When another student subsequently dropped out of a field trip to the Barringer Meteorite Crater Gerald took his place.  He became my father's research assistant, co-authoring "A Catalogue of the Leonard Collection of Meteorites" published in Contributions of the Meteoritical Society in 1951. 

After graduation from UCLA Gerald accepted a teaching position in the Department of Mathematics and Astronomy at the University of New Mexico.  He worked under the supervision of Lincoln LaPaz, Director of the UNM Institute of Meteoritics.  He received his M.S. in mathematics from UNM, leaving in 1956 to join the faculty of Long Beach City College.  In that same year he co-authored "An Index Catalog of the Multiple Meteoritic Falls of the World" and "The Classificational Distribution of the Single and Multiple Meteoritic Falls of the World."   Two years later he was elected Secretary of the Meteoritical Society, a position he held from 1958-1966.  These were both challenging times and times of transition for the Society.  Much had changed and much had been accomplished by the time he transferred the Society paperwork to the incoming Secretary, Roy Clarke.

When my father died in 1960, Gerald provided support to our family both during the period of my father's illness and after his death.  He participated in the creation of the Leonard Medal, and was one of those who presented it to my mother, Rhoda Leonard, in 1963.  In that same year he published the final catalog of the Leonard Collection of Meteorites which he had previously inventoried and helped transfer to UCLA.

Gerald loved music and sang in choirs most of his adult life.  As a school-age child I knew him as the family friend who joined us for our Christmas Eve celebrations.  He had a remarkable memory for dates, and he never missed a birthday or anniversary.  To the end of his life I could count on a note from him every year on the anniversary of my father's birth.

Gerald faced a number of serious medical challenges throughout his life.  The first, while a graduate student at UNM, almost took his life.  About the time of his retirement he was stricken with a rare form of Guillain-Barre syndrome that required months of hospitalization and left him with weakness from which he never fully recovered.  Yet he faced these and other obstacles with the grace and good humor that characterized him throughout his life.

Gerald also was the person who wrote the remembrance of my father that appeared in the first issue of Meteoritics when it resumed publication in 1963.  It is a privilege and an honor for me now to be able to write this remembrance of Gerald.

Fred Leonard

18:19 | Obituary

In Memoriam

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Lawrence A. Taylor (1938-2017)

A memorial for Larry Taylor submitted by Clive Neal (PDF)
18:02 | Obituary