2011 Annual Science Report

NASA Goddard Space Flight Center Reporting  |  SEP 2010 – AUG 2011

Exploring the Atmosphere of Mars at Infrared Wavelengths and the Organic Volatile Composition of Comet 2P/Encke

Project Summary

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 Ls = 8 – 83° (early through late spring in the Martian Northern hemisphere). Dr. Radeva also analyzed data acquired with the ultra-high resolution infrared spectrometer CRIRES at ESO’s VLT, and retrieved abundances and rotational temperatures from the spectral lines of O2 (a1Δg), used as a tracer for ozone. She presented spatial maps of ozone on Mars, and a comparison with models of the ozone distribution, at the annual American Geophysical Union meeting (December 2010). Dr. Radeva published a paper on results of her dissertation work, entitled “A Newly Developed Fluorescence Model for C2H6 ν5 and Application to Cometary Spectra Acquired with NIRSPEC at Keck II” (ApJ, 729, 2, 135). She also presented results of her analysis of the organic composition of comet 2P/Encke at the annual AAS Division for Planetary Sciences conference (October 2010).

4 Institutions
3 Teams
3 Publications
0 Field Sites
Field Sites

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 Ls = 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.

Figure 1. ​Emission spectral features of O2 (a1Δg) measured at ultra-high spectral resolution (λ/δλ =95,000) with CRIRES (detectors 2 & 3), on August 21, 2009. The spatial variation of residuals along the planet is shown, from North to South

  • PROJECT INVESTIGATORS:
  • PROJECT MEMBERS:
    Yana Radeva
    Postdoc

  • RELATED OBJECTIVES:
    Objective 2.1
    Mars exploration.

    Objective 2.2
    Outer Solar System exploration

    Objective 7.1
    Biosignatures to be sought in Solar System materials