The GTC exoplanet transit spectroscopy survey I: OSIRIS transmission spectroscopy of the short period planet WASP-43b

Understand

We used GTC instrument OSIRIS to obtain long-slit spectra in the optical range (520-1040 nm) of the planetary host star WASP-43 (and a reference star) during a full primary transit event and four partial transit observations.

• We integrated the stellar flux of both stars in different wavelength regions producing several light curves.
• We fitted transit models to these curves to measure the star-to-planet radius ratio, Rp/Rs, across wavelength among other physical parameters.
• We measure a Rp/Rs in the white light curve of 0.15988^{+0.00133}_{-0.00145}.