Carolus J. (Karel) Schrijver (1958-2024)

Dr. Carolus J. (Karel) Schrijver was a native of the Netherlands. As an undergraduate, he studied mathematics and physics, specializing in astrophysics, at Utrecht University. He continued at Utrecht and, under the guidance of Prof. Cornelis (Kees) Zwaan, received his Ph.D. in 1986. His thesis was entitled “Stellar magnetic activity: Complementing conclusions based on solar and stellar observations,” and this research led to stints working in the cool stars group headed by Dr. Jeffrey Linsky at the University of Colorado Boulder as well as an appointment at the European Space Agency’s ESTEC facility in Noordwijk. Following a multi-year fellowship from the Royal Netherlands Academy of Arts and Sciences, he joined the group at the Lockheed Martin Solar and Astrophysics Laboratory (LMSAL) in the mid 1990’s upon the invitation of Dr. Alan Title. For the next ~20 years, he continued at LMSAL until his retirement as a Senior Fellow in 2016.

Karel was an incredibly curious individual. He focused this intellectual curiosity on a broad range of solar and stellar astrophysics topics, including the evolution of magnetic fields on the photospheres of both the Sun and other cool stars, on understanding the resulting emission from solar and stellar chromospheres and coronae, and on how the observed solar activity signals fit into the panoply of activity indicators from other cool stars. At LMSAL, he helped to structure and implement compelling scientific goals of multiple NASA missions, including the Transition Region and Coronal Explorer (TRACE), the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) on the Solar Dynamics Observatory (SDO), and the Interface Region Imaging Spectrograph (IRIS). He served as a member of the Space Studies Board, and of the NASA Heliophysics Subcommittee (an earlier name for the Heliophysics Advisory Committee), as well as on numerous other NASA advisory committees and panels.

More recently, Karel helped to shape the original curriculum and edit the textbooks used for the highly impactful NASA Heliophysics Summer School, which each year presents the science of heliophysics as a broad and comprehensive discipline encompassing the full Sun-Earth system (and beyond) to a new round of early-career scientists. He was appointed Chair of the committee, sponsored by the larger Committee on Space Research (COSPAR) organization, that was tasked with gaining a consensus on how best to address and mitigate the impact of space weather on human society. The report from that interdisciplinary committee resulted in a global roadmap on the science of space weather (Schrijver et al. 2015) and the formation of International Space Weather Action Teams. Karel was selected as a Johannes Geiss Fellow of the International Space Science Institute of Bern, Switzerland for 2018, during which he created and edited the book “Principles of Heliophysics”, which illustrates how the different domains of heliophysics are integrated through universal processes.

In his spare time, with his loving wife, Dr. Iris Schrijver, they cared for their various pets, tended to their amazing garden, avidly traveled the world, and together wrote multiple popular-science books. In the year prior to his death, Karel wrote about his life experiences in an invited memoir (Schrijver 2023).

Karel had the rare ability to very quickly draw connections between disparate scientific ideas, hypotheses, and results that he encountered. As a colleague, mentor, and reviewer, he was always willing to provide both friendly encouragement and critical, but always constructive, feedback. He did not give up easily and rarely backed away from challenges and was served well by his joie de vivre and his ever-optimistic and forward-looking demeanor. Karel will be greatly and dearly missed.

Adapted and reproduced with permission from the Solar News obituary.

Schrijver’s AstroGen entry