Jason Cardelli died suddenly of a heart attack on May 14 at age 40 at the peak of his scientific career, a tragedy for family, friends and for our field. He is survived by his wife, Julia Mantle, brothers, James and John, sister, Laura, and his parents Aldo and Marilyn.
Jason was born on 1 December 1955 in Berwyn, lliinois and knew that he wanted to become an astronomer from the time he was in elementary school. He received his BS in astronomy from the University of Illinois in 1978 and his PhD in astronomy from the University of Washington in 1985.
While at Washington, Jason began studies of the properties of the diffuse interstellar medium. As a postdoc at the University of Wisconsin working with the HST Goddard High Resolution Spectrograph (GHRS) team, he matured as a scientist and soon became a principal investigator on numerous IDE, HST and NASA Astrophysics Data Program projects. In 1991, Jason was awarded a NASA Long Term grant to study interstellar dust and gas and their interaction. After nine years as a research scientist at Madison, Jason became associate professor of astronomy and astrophysics at Villanova University, just 18 months before his death.
During his short career Jason distinguished himself in research and as a teacher. He was very active in our profession, scoring many accomplishments within a tragically brief career. He was a meticulous, thorough and tireless researcher who set high standards for himself and expected the same from others. Jason published over 60 papers in the refereed literature and presented 10 invited reviews in his 10-year career. However, his legacy is not so much the quantity of his published papers as it is their quality and scientific importance.
Shortly after Jason arrived in Wisconsin, the Challenger disaster delayed all HST programs. He turned to work on interstellar extinction, expanding wavelength coverage to include the NIR through UV. The culmination of this work was the discovery of a family of mean extinction laws applicable to a wide range of interstellar dust environments.
With the launch of HST in 1990, Jason turned his attention to GHRS and UV absorption line spectroscopy of the interstellar medium. He obtained precision measurements which he used to obtain accurate abundances for C, N, O, Si, Fe, and Mg, elements crucial for understanding the composition of interstellar dust and how gas cools in diffuse clouds.
As part of the GHRS team, Jason contributed to modeling the noise characteristics of the instrument, pushing the system to the limit of its observational sensitivity. Jason's goal was to measure interstellar abundances. His Kr observations revealed an interstellar abundance 2/3 of the solar value, which informed our understanding of galactic chemical evolution. Jason also measured abundances for other rare elements which should ultimately provide important clues about the nature of s and r process element enrichment of the interstellar medium. He was working on the abundance of interstellar C at the time of his death. Jason also worked to improve our understanding of the fundamental data for atomic transition probabilities which are essential for obtaining accurate abundances for the interstellar medium. He collaborated in an effort to define self-consistent sets of oscillator strengths.
Jason was an activist in the profession, concerned with problems of funding and employment. His pro-active nature led him to found the Association of Research Astronomers (ARA). This ad hoc organization focused attention on the plight of the growing number of professional astronomers working outside the traditional university system. Even after Jason obtained a tenure track position at Villanova, he remained active in the ARA, broadening its scope to include issues concerning researchers at smaller universities and colleges. Jason organized a special session at the 187th meeting of the AAS to draw attention to the impact of shrinking research budgets on the research potential of astronomers in non-traditional positions or at smaller institutions.
As a member of the AAS Nominations Committee Jason pushed for broader representation seeking candidates who might expand the scope of the Society. He felt that all astronomers should have input into casting scientific policy, and he had hoped that a more pro-active AAS might provide that input. Jason's death silenced the loudest voice for pluralism in the astronomical community, and that voice will be difficult to replace.
Jason was a virtuoso lecturer. His exuberance was unparalleled, conveying a sense of excitement about his work and his feelings. These attributes, together with Jason's meticulous eye for detail, tireless preparation and an artistic flare for visual presentations (he also had a strong interest in graphic art) made him an outstanding teacher. Finally, Jason will be missed beyond astrophysics. He was just plain fun to be around. Jason was witty, open and genuine (a rare combination) and his enthusiasm was infectious. Those of us who knew him well, will miss him always.