Profile of Ewine F. Van Dishoeck

PROFILE Profile of Ewine F. van Dishoeck he infinite vastness of space, pleasant conversation, he invited van the infinitesimal compactness of Dishoeck to study with him at Harvard a single molecule; comprehend- for a few months, which she did in 1980 ing the size of either object can after receiving her master’s degree in Tbe mind-boggling, and understanding chemistry from Leiden. ‘‘And that pe- the nature of either can be a life’s work. riod was enough for the Dutch authori- Yet for the past 25 years, astrophysicist ties to give me a grant to do research in Ewine van Dishoeck has made a career this field, even though there wasn’t for- of bridging the gap between space and mally a professor in that field,’’ she says. the single molecule. As Professor of Molecular Astrophysics at the University East to West Coast of Leiden (Leiden, The Netherlands) as Upon completing her Ph.D. thesis on well as director of Leiden’s Raymond photodissociation and excitation of in- and Beverly Sackler Laboratory for As- terstellar molecules in 1984, van Disho- trophysics, van Dishoeck has spent her eck received one of Harvard’s Society of career studying the chemistry and evolu- Fellows positions, which allowed her to tion of the myriad molecules sprinkled continue her research in Dalgarno’s lab- throughout the universe. oratory, where she had made frequent Of particular interest to her are inter- visits while completing her degree. The stellar clouds, regions that appear jet opportunity presented a small problem, black in optical wavelengths but are however, in that de Zeeuw, whom she densely packed with the raw materials had recently married, received a fellow- that give birth to stars and planets. Ewine van Dishoeck ship at the Institute for Advanced Study Along with a multitude of collaborators in Princeton, NJ. ‘‘Interestingly, we had in Europe and the United States, van the opportunity to have two positions Dishoeck, elected to the National Acad- At Leiden, van Dishoeck found that in the Princeton area or two positions in emy of Sciences as a foreign associate in physics interested her, and her interests the Harvard area,’’ she says, ‘‘but the 2001, has studied the chemical evolution began shifting toward chemical physics, advice we got from some of the more of the molecules within these clouds as and especially quantum chemistry, on senior people was that in the long run, they condense into stellar and planetary which she did her senior project. van it’s better at the earlier stages to take bodies. As summarized in her Inaugural Dishoeck was determined to continue the steepest road in terms of your ca- Article in this issue of PNAS (1), which with quantum chemistry in graduate reer so that later on you have the better is also part of a Special Feature on school, but soon after she started, the papers to be together in one place.’’ Interstellar Chemistry, recent improve- professor who specialized in quantum And because Harvard was the best place ments in astronomical instrumentation chemistry at Leiden died. ‘‘The way for van Dishoeck, and Princeton the have enabled van Dishoeck and other [Ph.D. programs] work in Holland is best place for her husband, they decided molecular astrophysicists to observe in that you can only do a thesis under to live apart for the time being. detail low-mass protostellar regions sim- a full professor,’’ says van Dishoeck, At Harvard, van Dishoeck’s work was ilar to those around the Earth’s primi- ‘‘and it became clear that the university principally a continuation of her thesis tive sun, thus providing some of the first wouldn’t come to a consensus on a re- project, studying the photodissociation clues about the chemical origin of the placement for quite some time.’’ Thus, of molecules in interstellar clouds or solar system. if van Dishoeck wanted to stay at Lei- comets (2–4). She studied ‘‘how rapidly den for her graduate work, she needed a molecule falls apart under UV radia- A Not-So-Chance Encounter to find another field of study. tion and what are the basic molecular Although born and raised in Leiden, van At that time, van Dishoeck’s boy- processes by which this occurs,’’ she Dishoeck’s brief stopover in the United friend, Tim de Zeeuw, was studying as- says. ‘‘We know this process from our States as a youth launched her scientific tronomy and had just finished a course own atmosphere and ozone. There’s a journey. When she was 12, her father, a on the interstellar medium and the re- prime example of a molecule that is recently retired professor of ear, nose, cent discoveries of interstellar mole- photodissociated into an oxygen mole- and throat medicine, was invited to cules. van Dishoeck recalls that he told cule and an oxygen atom, which then, spend 6 months in San Diego, CA. van her, ‘‘Well, isn’t this something for of course, is a large cause for the ozone Dishoeck took her first science class in you?!’’ van Dishoeck knew nothing hole.’’ the San Diego public school system. She about astronomy but learned that the van Dishoeck also studied molecules remembers that her science teacher, preeminent expert of the interstellar as diagnostic tools for studying certain who as a female and African-American medium was Alex Dalgarno at Harvard processes in interstellar clouds. ‘‘For in the 1960s had undoubtedly overcome University (Cambridge, MA). That sum- example, if you look at the beautiful some obstacles to reach her position, mer, as fate or fortune would have it, nebulae in the sky, you want to know did an outstanding job of fostering in van Dishoeck and her boyfriend were how warm or how dense they are,’’ she van Dishoeck an interest in science and camping in Canada’s Mont Tremblant says. ‘‘So we spent some time looking providing career inspiration. When van National Park and heard that the park at the excitation of various molecules Dishoeck returned to The Netherlands, was hosting a major astronomy confer- her high school chemistry teacher ence. ‘‘We got up the courage to go up This is a Proﬁle of a recently elected member of the National opened up the wonderful world of mole- to this conference and see if Professor Academy of Sciences to accompany the member’s Inaugural cules for her, and she went on to study Dalgarno was there,’’ she says. Dalgarno Article on page 12249. chemistry at the University of Leiden. was indeed present, and after a brief, © 2006 by The National Academy of Sciences of the USA www.pnas.org͞cgi͞doi͞10.1073͞pnas.0604740103 PNAS ͉ August 15, 2006 ͉ vol. 103 ͉ no. 33 ͉ 12229–12231 Downloaded by guest on September 25, 2021 board, the Short Wavelength Spectrom- eter, had been built in The Netherlands. The principal investigator for that project, Thijs de Graauw, had guaran- teed time on the satellite, and he kindly offered some time to van Dishoeck. The ISO was scheduled to launch in 1992, but as is common with such space projects, multiple delays pushed the launch to 1995. The delay was actually a blessing in disguise. In 1992, Mayo Greenberg, who had set up Leiden’s first astrophysics laboratory in the 1970s, reached the mandatory retire- ment age of 70. At the time, van Disho- eck felt it was important to keep the astrophysics laboratory up and running. ‘‘The ball sort of got in the court of astronomy, and they turned to me and said, ‘Well, Ewine, is this something for you to take under your wing?’ and I said, ‘Well, I’m not really a laboratory person,’ but I could see that [Green- berg’s] lab was set up to do exactly the kind of experiments that we needed to do in order to interpret the data from van Dishoeck, with husband Tim de Zeeuw, in front of the APEX 12-m telescope, Atacama Large Millimeter the ISO satellite.’’ So, by scraping Array (ALMA) site, Chajnantor, Chile, 2005. money together from various sources, van Dishoeck took over the laboratory and kept it going for several more pro- because the ratios can tell you about only when you go to longer wavelengths ductive years, while she collected her how often and how hard a molecule col- that you start to find something.’’ first observations from the ISO satellite. lides.’’ In turn, van Dishoeck notes, ‘‘We were able to identify several new these values could be related to molecu- Return to Holland species in the solid state and at the lar parameters, and so these molecules van Dishoeck spent two fruitful years at same time learn more about the chemi- could be turned into long-distance ther- CalTech, but in 1990, her husband was cal evolution of these regions in which mometers and pressure gauges, thus al- offered a full professorship at the Uni- new stars are being formed,’’ she says. lowing for the design of comprehensive versity of Leiden. van Dishoeck was models of these clouds (5). offered an associate-level position at After her Fellows program concluded, Leiden, one that included many grants ‘‘If you look at van Dishoeck reunited with her husband to help start her own research group. at Princeton for one year as a visiting ‘‘Both of us really enjoyed the United the beautiful nebulae professor, ‘‘which was very nice. Cer- States, and I certainly would have loved tainly after two and a half years, we had to stay a little bit longer at CalTech,’’ in the sky, you want more than enough of this commuting!’’ she says of the tough decision to return she says.

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