Systematic search for exoplanet phase curves in TESS data

Abstract

We carried out a systematic search for phase curve variations in the TESS data. Our goal is to study whether the planetary albedos and surface/atmospheric emissions of the planets depend on orbital period/insolation. We are also interested to determine the limit in terms of scaled semi-major axis until that points TESS is able to detect the secondary transits. This allows us to make predictions how successful PLATO can be in the detection of phase curves and secondary transit events at different orbital distances and magnitudes. To reach this goal, we decided to re-analyze all transiting exoplanet light curves from the Transiting Exoplanet Survey Satellite in the range of period 0-30 days and TESS-magnitude 6-12. We selected only those systems where 2 minute cadence (or shorter) light curves were available and a radial velocity curve was published previously. We used Transit and Light Curve Modeller and we carried out joint radial velocity and light curve fits with different limb darkening laws (quadratic and power-2) as well as we fitted the light curve with and without phase curve variations (reflection, beaming and ellipsoidal effects and possible occultation event was also included). We also treated the noise with the successful wavelet-based noise model which was simultaneously fitted with the transit and phase curve model. This approach overpasses the preliminary similar studies where only the light curves were fitted without radial velocities, or the photometric noise was not managed in the photometric data with a simultaneous fit. This work is a logical continuation of the work we presented in the previous all-hands on the desk meeting where we have shown that the wavelet-based noise treatment method is a very effective tool to remove the stellar activity, pulsation and instrumental noise. The result is the most extensive dataset of accurate, precise and homogeneous catalogue of transiting exoplanet data.