June 2018 Letter from the Director
DTM's Role in International Science
Last month I wrote about DTM serving as a center for science discussion in the Washington, DC area. This month I'll highlight the department's role in the broader national and international science community. Perhaps the most newsworthy development in this regard relates to DTM staff scientist Larry Nittler's role on the science team for Japan's Hyabusa2 mission to the Ryugu asteroid. The spacecraft reached its target last week and is beginning to return pictures of the spinning-top shaped asteroid. For the next year and a half, the spacecraft will determine the topographic, temperature and mineralogical characteristics of Ryugu's surface. Four separate rovers will land and provide detailed study of the asteroid's surface. The mission also will deploy an explosive device to create a crater on Ryugu's surface while the main spacecraft flees to safety on the other side of the asteroid. The final component of the mission will be return of samples from Ryugu that will reach Earth near the end of 2020. This is where Nittler's role will become most important, as he is a world-recognized leader in the characterization of small amounts of extraterrestrial material. His expertise, coupled with the excellent sample characterization and analysis facilities available on the BBR campus, will allow DTM to play an important role in Japan's effort to determine the composition of Ryugu and the manner in which such primitive asteroids formed early in Solar System history.
Left: DTM volcanologists Diana Roman (left) and Kathleen McKee installing one of the Carnegie Quick Deploy Boxes at Stromboli Volcano. Right: Hélène Le Mével doing a maintenance visit to the gravimeter instrument used at Stromboli in May 2018. Pictures by Hélène Le Mével, DTM.
In another project that involved a somewhat shorter voyage, DTM scientists this month ventured to Italy to study the ongoing eruptions at Stromboli volcano. The project, led by DTM's NSF Postdoctoral Fellow Kathleen McKee, and involving staff scientists Diana Roman and Hélène Le Mével, combined infrasound, gravity and gas emission measurements with one of the first large-scale deployments of the quick-deploy seismic stations developed by Roman and DTM's Lara Wagner. The combination of ultrasound, gravity, gas and seismic measurements obtained during this expedition will provide important insights into the dynamics of magma movement underground and the physical processes that are influencing the eruptions at this long-active volcano.
A different example of DTM's reach internationally is the summer school I participated in on the Origin of the Earth-Moon System. This workshop was organized by the Transregional Collaborative Research Center (TRR-170), a consortia of German university groups funded by the DFG, the German equivalent of the U.S. National Science Foundation. The TRR 170 effort involves research scientists from 5 German universities or museums who are currently pursuing 14 different projects that support 9 postdocs and 18 doctoral students. The goal of the effort is to provide a better understanding of the late stages of planetary growth in our Solar System; a time period that could be critical in establishing planetary habitability through the delivery of the volatile components (e.g. water, carbon) that constitute life, but also limiting habitability through a heavy flux of impactors that would, in essence, represent extinction events every few thousand years.
Besides being a research topic also pursued at DTM, one of the leaders of the consortia is Dr. Harry Becker of the Freie Universitat Berlin. Harry was a postdoc at DTM from 1995-1997. Harry's leadership of this large research effort is a good example of the important role that DTM has played in the postdoctoral training of many of the current leaders of Earth and planetary science research worldwide. This is by one-on-one interaction between staff scientists and postdocs in research, but also through our monthly postdoctoral workshops where we explore a wide variety of career-related topics to provide a strong foundation for success as the postdocs move from DTM into their careers. Roberto Molar, DTM's Science Writer and Communications Coordinator, is working on a series of spotlights about our prominent alumni, so I encourage you to watch the DTM web page for the appearance of this series. They will follow a similar format to the spotlights Roberto has written for current DTM postdocs. My expectation is that they will provide an interesting glimpse at how the aspirations of our current postdocs can come true as they develop successful careers, and will showcase the importance of a small department like DTM on the career development of those now leading the world's research community.
Detecting the Early Stages of Planet Formation
An artist’s impression of protoplanets forming around a young star, courtesy of NRAO/AUI/NSF; S. Dagnello
A research highlight to report this month is DTM's Rubin Postdoctoral Fellow Jaehan Bae
's role in developing a method to confirm the existence of a planet in the process of forming within a circumstellar disk
. The amazing images coming from the Atacama Large Millimeter Array (ALMA) telescope in Chile are illuminating the complex structure of circumstellar disks of dust and gas. Most famous, so far, are the images of HL-Tauri that show large gaps in the disk around this star. The gaps are interpreted as reflecting the areas where unseen planets are sweeping up the dust in their orbits, growing larger in the process. The work done by Bae and collaborators used theoretical predictions of the influence of the gravity of these growing planets on the surrounding gas in the disk. Observations of gas velocity in these regions allow more precise determination of the masses and locations of "baby" planets forming in the disk.
More discoveries are on tap in the coming weeks, as soon as the news embargo on the publication of the accompanying papers is lifted. Please stay tuned to the DTM web page for news on these latest discoveries about the world around us.