Atmospheric characterization of TESS planet HD219666b

TESS has been highly productive in detecting new exoplanets since launch and HD219666b was the first hot Neptune discovered by TESS in sector 1. The high equilibrium temperature (~1000K) and bright host star (V=9.81) make it a great target for follow up atmospheric characterization with HST and JWST. Here we present our preliminary transmission spectra of HD219666b using HST with WFC3 G141 and G102 grisms.