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Coronagraphs

Coronagraphs allow us to see planets up against their bright host stars by blocking light from the host.  Excitingly, NASA's WFIRST mission will likely launch with a pair of coronagraphs that will allow us to image worlds around our nearest stellar neighbors.  In Robinson et al. (2016), we explored to what extent these coronagraphs will be able to detect certain atmospheric gases for a variety of worlds, from Earth-like planets to gas giants.  These models, including WFIRST-specific cases and a generalized model, are available on GitHub.  Hopefully community members will find these useful for generating "faux" noisy spectra for WFIRST-related studies.  As an example, the spectrum below shows an example of what WFIRST could do for a cool Jupiter (i.e., receiving about seven times the insolation as our Jupiter) around a Sun-like star at 6 parsecs, assuming an integration time of 20 hr (per coronagraph bandpass).  Pretty impressive!



Example spectrum and photometric observations from WFIRST for a cool Jupiter orbiting a Sun-like star at 6 parsecs. The photometric points (indicated by colored horizontal bar) at the shortest wavelengths are for the Hybrid Lyot Coronagraph, while those at the longer wavelengths at the methane "on" and "off" filters for the Shaped Pupil Coronagraph. Spectral points are also from the SPC paired with a Integral Field Spectrometer.  The solid red line is the noise-free spectrum.