DETECTION OF THE EXTRASOLAR PLANET WASP-33B USING COLOR FILTER ANALYSIS

The presence of extrasolar planets (“exoplanets”) is commonly deduced via the stellar magnitude method of observation in which a time-series of images records the temporary reduction in magnitude (or relative flux) resulting from obstruction of some of the star’s light by the orbiting exoplanet. This method is often used by amateur astronomers, who now play a significant role in exoplanet validation.

The study’s purpose is to refine exoplanet observation practices by investigating how the color of the filter on a monochrome CCD camera affects recorded sensitivity to the relative flux of the star WASP-33 and, consequently, the ability to detect the transit of WASP-33’s exoplanet, WASP-33b. It is hypothesized that if the star’s recorded relative flux is affected by filter color, then when Red, Green, and Blue filters are utilized to image bluish-white star WASP-33, the Blue filter images will demonstrate the highest photometric sensitivity. A CCD and 250mm telescope were utilized to capture three color-filter series of “light” images during the transit period. Differential photometry was performed on the target and comparison stars; light curves were plotted. To evaluate photometric sensitivity, the standard deviation of the relative flux (in lumens) of WASP-33 was calculated for the Red, Green, and Blue series (0.003423, 0.005806, and 0.007162, respectively). A comparison of these values confirmed the hypothesis. Additionally, all three series showed the temporary reduction in flux necessary to validate the exoplanet transit. By improving amateur astronomers’ astrophotometry practices, these findings can increase the quality of photometric data utilized by professional astronomers.