This session is focused on the interplay between transiting planets and their host.
The session will address how the knowledge of stellar atmosphere's properties affects the determination of the characteristics of the planet and its atmosphere and, for example, what are the limit posed by limb darkening modeling in the recovery of the planet parameters. Statistical tools allowing the measurement of stellar and planetary properties will be presented. The session will then move to the presentation of early science results from the Next Generation Transit Survey (NGTS). Finally, the role of stellar winds and cosmic rays in shaping the environment close to terrestrial exoplanets will be discusses, and the particular case of what happen to planets orbiting stars in the latest stage of stellar evolution.