Title of programme: Confirming the Eclipse Variability of the Ultrahot Neptune, LTT 9779b
Abstract: The study of the chemistry, dynamics, and evolution of exoplanetary atmospheres is providing a treasure-trove of discoveries that are allowing us to understand the nature of planets in the galaxy to an extent not previously possible. Although most efforts have been focused on hot Jupiters, (given they represent the best target population due to their relatively large atmospheres), we are still only scratching the surface. More recently, hot Neptune-like exoplanets have been found orbiting stars bright enough that we can perform detailed atmospheric analyses. One standout member of this population is LTT 9779b, the first Ultrahot Neptune, a rare world that orbits its star in only 19 hours, placing it firmly in the Neptune Desert. Using CHEOPS we observed 10 eclipses of the planet behind the star, yet only six of the light curves show evidence for any occultation, and they show surprisingly deep eclipses of >100 ppm. Therefore, it is highly possible that we are witnessing the evolution of the reflective layer of the planet's atmosphere, being modulated by its rotational spin. In order to confirm planetary eclipse variability for the first time for such a world, we request an additional 10 eclipse observations, such that we can search for a modulating signal, building up the statistics to allow for a robust detection. We shall then use the latest global circulation models to precisely constrain the scattering properties of the layer, along with its temporal evolution.
Temporal Coverage
2022-09-28T02:51:53Z / 2022-09-28T11:06:00Z
Version
3.0
Mission Description
CHEOPS (Benz et al., https://doi.org/10.1007/s10686-020-09679-4) is a European Space Agency (ESA) mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden and the United Kingdom.
The satellite has a single payload comprising an ultra-high precision photometer covering the 330 - 1100 nm wavelength range in a single photometric band. Observations are made as part of the Guaranteed Time Observing Programme that is formulated by the CHEOPS Science Team, and the Guest Observers Programme through which the Community at large can apply for CHEOPS time.
