2014/10/14 by J. R. Burton, C. A. Watson, P. Rodríguez-Gil +5 · 1 citation
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Absorption (acoustics) #Absorption spectroscopy #Astronomy #Astrophysics #Atmosphere (unit) #Atmospheric Ozone and Climate #Computer science #Exoplanet #Meteorology #Optics #Photometry (optics) #Physics #Spectroscopy #Spectroscopy and Laser Applications #Stars #Stellar, planetary, and galactic studies #Telecommunications #Transit (satellite) #Transmission (telecommunications) #Wavelength #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stu2149
published as MNRAS, 2015, 446, 1071-1082 · 14 pages, 12 figures, 2 tables - MNRAS accepted
arxiv created 2014/10/14 · openalex publication_date 2014/11/17 · arxiv updated 2014/11/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We report on a pilot study of a novel observing technique, defocused transmission spectroscopy, and its application to the study of exoplanet atmospheres using ground-based platforms. Similar to defocused photometry, defocused transmission spectroscopy has an added advantage over normal spectroscopy in that it reduces systematic errors due to flat-fielding, point spread function variations, slit-jaw imperfections and other effects associated with ground-based observations. For one of the planetary systems studied, WASP-12b, we report a tentative detection of additional Na absorption of 0.12 ± 0.03[+0.03] per cent during transit using a 2 Å wavelength mask. After consideration of a systematic that occurs mid-transit, it is likely that the true depth is actually closer to 0.15 per cent. This is a similar level of absorption reported in the atmosphere of HD 209458b (0.135 ± 0.017 per cent; Snellen et al. 2008). Finally, we outline methods that will improve the technique during future observations, based on our findings from this pilot study.