Simulated OASIS Venus Spectra

OASIS is a theoretical tool capable of modeling the environment of planets and it can also be used to plan observations or build new ideas for observational methods.

Simulated Flux

Fluxes coming from the simulated Venus planet, which include the emitted planet flux and the stellar radiation being reflected in the planet (obtained from the 3D simulations). The spectral resolution used in the figure is the same as the resolution used in the 3D simulations.

 The colored solid lines represent the flux coming from the day side (red) and night side (blue) of the planet. The impact of the clouds is very clear for wavelengths shorter than 4 microns. The clouds are very reflective and help to signifi cantly raise the outgoing flux. 

Contribution Function

The fluxes at different wavelength contain information from different regions in the atmosphere. A good diagnostic to explore from which pressure range the planet emission flux emerges is the contribution function.

The peak shape features in the contribution function maps are related to the main absorption features of CO2, for example at roughly: 1.6, 2, 2.7, 4.3 and 15 microns. For wavelengths longer than 10 microns the emitted flux contributions are from pressures above the 1 bar level.

Figures below show the observed spectra for different telescope diameters and 10 hours of observation time. The Venus analog was placed 10 pc away. The spectral range observed is the same as the one proposed for the spectrograph in the LUVOIR concept mission. The instrument parameters are based on the work of Robinson et al. (2016).

Figure on the left – 8 meters telescope diameter (D): The blue points represent an inner working angle of 3lambda/D, which would only allow for observations at wavelengths shorter than 1 microns. It would be difficult to characterize the atmosphere from the data corresponding to the blue points, where the only information observed would be the reflected light from the cloud structure. With an inner working angle of 2lambda/D (green points) we would be able to capture the H2O feature at roughly 1.2 microns. The red points represent an inner working angle of lambda/D.

Figure on the right – 15 meters telescope diameter (D): signifi cantly improves the performance of the instrument, it would make it possible to observe the H2O and CO2 features with all the inner working angles tested: 3lambda/D (blue), 2lambda/D (green), and lambda/D (red). 

8 meters LUVOIR
15 meters LUVOIR