Helmut Abt
The staff of NSF NOIRLab grieve at the passing of Dr. Helmut A. Abt, reflect on his remarkable career, and celebrate his scientific legacy. He was a towering figure in U.S. astronomy: on top of his scientific research, he contributed in several critical ways to the formation and evolution of the national observatories and, of course, as the longest serving editor of The Astrophysical Journal, which has been a premier journal for astronomy and astrophysics. He was awarded the George Van Biesbroeck Prize (given by the American Astronomical Society [AAS] “for long-term extraordinary or unselfish service to astronomy”) in 1997.
Dr. Abt emigrated with his parents to the U.S. from Germany when he was two years of age and grew up first in Jamestown, New York, and then in the Chicago area. After obtaining a BS in mathematics and MS in Physics, both from Northwestern University, he was the very first to earn a PhD from the then newly formed Astronomy program at the California Institute of Technology. His thesis on W Virginis stars elucidated the detailed dynamical processes in the atmospheres of pulsating stars.
He continued this line of work on RV Tauri stars during his subsequent position at Lick Observatory, expanding on the cyclical propagation of shocks in pulsating stars of old stellar populations. His detailed results were not universally accepted at the time, but were validated some 50 years after his work on this topic. He next had a position at the Yerkes Observatory, then operated by the University of Chicago, where he went on to be appointed as Assistant Professor. Carl Sagan was among the students he taught. During this period he was also involved with the McDonald Observatory in Texas. He continued his observational work with the telescopes there, directing his focus on the variability of supergiant stars.
At this time he also joined the effort established by the McMath Committee and led by Aden Meinel to search for a suitable site in the continental U.S. for establishing a national observatory that would provide observational access to astronomers from any institution. He was part of a small team that surveyed several sites in Texas, New Mexico, and Arizona — sometimes the visits to the mountain peaks (as for Kitt Peak) had to be done on horseback. A lively first person account of this work is available in chapter 5 of his autobiography, A Stellar Life. This is how the Kitt Peak site was eventually selected and how Dr. Abt’s efforts are directly linked to the genesis of the national observatories, which have evolved to become today’s NOIRLab.
Dr. Abt was hired by AURA in 1959 and became full Astronomer in 1963. One of the tasks he took on was to build up the library for what was then the Kitt Peak National Observatory (KPNO), headquartered in Tucson, and its sister observatory in Chile, the Cerro Tololo Inter-American Observatory (CTIO). To find back issues of journals, he tapped the private collections of astronomers. The holdings of the NOIRLab libraries today rival other excellent astronomy collections. Dr. Abt’s enthusiasm and efforts contributed greatly to this achievement.
Following better understanding of the Kodak photographic emulsions and uniform dispersion from the new grating spectrographs at the Kitt Peak 84-inch telescope, Dr. Abt obtained new data for a photographic spectral classification atlas, which he compiled in 1968. This was incorporated in 1978 into The Revised MK Spectral Atlas for Stars Earlier than the Sun by Morgan, Abt, and Tapscott. It serves as the seminal reference for photographic spectral classification using grating spectrographs that provide linear dispersions.
His work on the binary frequency among stars of different types, which appears to have originated with his work in the 1960s on Am and Ap stars, was carried out over several decades. Publications by him on these topics can be found as late as 2018. His result that over 55% of solar type stars show multiplicity came as a surprise at the time, even as it paved the way for the discovery of the first planets by others.
Dr. Abt was a prolific author, publishing 219 refereed science articles as first author and 26 as co-author. In addition, he published 146 non-refereed articles as first author and 16 as co-author. His latest publication appeared in October 2024. A listing of his publications are available in an ADS public library.
Dr. Abt took over as Editor in Chief of The Astrophysical Journal (ApJ) in 1971 from S. Chandrasekhar and continued in this position until 1999, past his formal retirement from NOAO in 1996. As his final act as Editor in Chief, Chandrasekhar had arranged for the ownership of the ApJ to pass to the AAS, so Dr. Abt was the first to serve in this capacity under the auspices of the AAS. This was a period of rapid growth in publications, and the ApJ family (including the Supplements and the Letters) grew by more than a factor of three under his leadership. To cope with this growth, he initiated the practice of enlisting Science Editors from the community. He also became engaged in bibliometrics, parsing the history of publications in astronomy and astrophysics in ways that have, among other things, informed management decisions at the national level. Towards the end of his tenure at the ApJ, he managed the transition to electronic peer review and publication. A detailed account of his tenure as Editor in Chief can be found in chapter 12 of A Stellar Life.
During this period, he would be seen in his office late in the night, with classical music from his stereo wafting down the hallways (he was a lifetime patron of the Arizona Friends of Chamber Music). His cat would often accompany him at night and roam the hallways.
He loved his visits to China. He loved his role as an advisor to Chinese colleagues, and they in turn loved his inspiring presence. True to his faith in the importance of libraries, he donated his own personal complete collection of the ApJ to Tsinghua University in Beijing. His work in stimulating astronomy there was recognized by the Chinese Friendship Award, the highest award bestowed by the People’s Republic of China for “foreign experts who have made outstanding contributions to the country’s economic and social progress.”
Helmut Abt will be remembered by staff in Tucson, and the many many postdocs and other early career visitors who have passed through Tucson, as an avuncular mentor, quick with his smile and laugh and encouragement. His breadth of knowledge was breathtaking. Even after he stepped down as editor of the ApJ, he would come in to work daily when he was not traveling, driven by his passion for astronomy and the work that he loved. His presence will be missed, but his passion, integrity, and hard work will continue to inspire us into the future.
In addition to his autobiography A Stellar Life, additional accounts about Dr. Abt can be found at the following links:
Personal Interview: https://www.aip.org/history-programs/niels-bohr-library/oral-histories/23364
NOIRLab staff reflections: https://noirlab.edu/public/blog/reflections-helmut-abt/
Wikipedia: https://en.wikipedia.org/wiki/Helmut_Abt