First exoplanet transit observation with the Stratospheric Observatory for Infrared Astronomy: Confirmation of Rayleigh scattering in HD 189733 b with HIPO

TL;DR

This paper reports the first exoplanet transit observation using SOFIA, confirming Rayleigh scattering in HD 189733 b's atmosphere through simultaneous multi-band photometry, demonstrating SOFIA's capability for precise exoplanet studies.

Contribution

It is the first successful exoplanet transit observation with SOFIA, showcasing its potential for absolute transit photometry and atmospheric characterization.

Findings

Confirmed Rayleigh scattering in HD 189733 b's atmosphere

Demonstrated SOFIA's capability for simultaneous multi-band transit observations

Provided insights into atmospheric scattering sources

Abstract

Here we report on the first successful exoplanet transit observation with the Stratospheric Observatory for Infrared Astronomy (SOFIA). We observed a single transit of the hot Jupiter HD 189733 b, obtaining two simultaneous primary transit lightcurves in the B and z' bands as a demonstration of SOFIA's capability to perform absolute transit photometry. We present a detailed description of our data reduction, in particular the correlation of photometric systematics with various in-flight parameters unique to the airborne observing environment. The derived transit depths at B and z' wavelengths confirm a previously reported slope in the optical transmission spectrum of HD 189733 b. Our results give new insights to the current discussion about the source of this Rayleigh scattering in the upper atmosphere and the question of fixed limb darkening coefficients in fitting routines.