Infrared transmission spectrum for Kepler-79d

With masses in the super-Earth range (1-10M{Earth}) and radii akin to those of giant planets (>4R{Earth}), their large envelopes may have been accreted beyond the water snow line and many appear to be susceptible to catastrophic mass loss. Both the presence of water and the importance of mass loss can be explored using transmission spectroscopy.

Here, we present new Hubble space telescope WFC3 spectroscopy and updated Kepler transit depth measurements for the super-puff Kepler-79d. We do not detect any molecular absorption features in the 1.1-1.7{mu}m WFC3 bandpass, and the combined Kepler and WFC3 data are consistent with a flat-line model, indicating the presence of aerosols in the atmosphere. We compare the shape of Kepler-79d transmission spectrum to predictions from a microphysical haze model that incorporates an outward particle flux due to ongoing mass loss.