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Project Progress

Yana L. Radeva is a Research Associate at The Catholic University of America, conducting her postdoctoral research at NASA’s Goddard Space Flight Center. During the time period September 1, 2010 – August 30, 2011, she analyzed high-resolution infrared spectra of the Martian atmosphere, searching for biomarker gases (such as methane), and studying the spatial distribution, diurnal and seasonal evolution of trace species. Dr. Radeva analyzed data-sets acquired with the NIRSPEC instrument on the Keck II telescope during the 2009-2010 observing campaign, covering a range of L_s = 8 – 83° (early through late spring in the Martian Northern hemisphere). Dr. Radeva contributed to the development of an automatization of the algorithms used for the spectral analysis, and completed the preliminary reduction of all data-sets, extracting residuals spectra of the Martian atmosphere.

In October 2010, Dr. Radeva presented results of her PhD dissertation research, on “Organic Depletion and Low Rotational Temperatures in Comet 2P/Encke, Revealed Through Infrared Spectroscopy”, at the annual American Astronomical Society Division for Planetary Sciences conference in Pasadena, CA. Dr. Radeva presented production rates and mixing ratios for H₂O, CH₄, C₂H₂, C₂H₆, CH₃OH, H₂CO, and HCN, measured on November 4, 5 and 6, 2003. Dr. Radeva also gave a talk on the diversity in cometary volatile composition, and the infrared spectroscopic measurements of 2P/Encke, at the Planetary Science Seminar for the Director of Science and Exploration at NASA Goddard Space Flight Center. In addition, Dr. Radeva’s dissertation was nominated for the University of Maryland Distinguished Dissertation Award.

In December 2010, Dr. Radeva presented results of her work on “Mapping of Ozone on Mars at Infrared Wavelengths using CRIRES at VLT” at the annual American Geophysical Union meeting in San Francisco, CA. Dr. Radeva analyzed data acquired on August 21, 2009, with the ultra-high resolution infrared spectrometer CRIRES at ESO’s VLT, and extracted abundances from the spectral lines of O₂ (a¹Δg) (Figure 1). She retrieved rotational temperatures for both O₂ (a¹Δg) and CO₂, and used O₂ (a¹Δg) as a tracer for ozone in the Martian atmosphere. Dr. Radeva presented spatially resolved maps of ozone and compared its spatial distribution with predictions by Lefevre et al. (2004), based on their 3-D model. Dr. Radeva was also co-author of the following presentations at the AGU meeting: “A Deep Search for Biomarker Gases on Mars in 2009 – 2010: The Campaign and a Few Preliminary Results”, Mumma, M. J., Villanueva, G. L., Novak, R., Radeva, Y. L., Kaufl, H., Smette, A., Hartogh, P., Encrenaz, T.; and “Water on Mars: global maps of H₂O, HDO and D/H obtained with CRIRES at VLT and NIRSPEC at Keck II”, Villanueva, G. L., Mumma, M. J., Novak, R., Radeva, Y. L., Kaufl, H., Smette, A., Hartogh, P., Encrenaz, T.

In March 2011, Dr. Radeva published a paper in the Astrophysical Journal on further results of her dissertation work: “A Newly Developed Fluorescence Model for C₂H₆ ν₅ and Application to Cometary Spectra Acquired with NIRSPEC at Keck II”, Radeva, Y. L., Mumma, M. J., Villanueva, G. L., A’Hearn, M. F., 2011, ApJ, 729, 2, 135. Dr. Radeva’s fluorescence model of C₂H₆ ν₅ can be used to retrieve rotational temperatures of ethane, and contributes to the study of the physics of cometary comae, and the accurate modeling of the terrestrial atmosphere.