PyStarshade: Simulating High-Contrast Imaging of Exoplanets with Starshades

A key challenge in detecting exoplanets and characterizing their atmospheres is distinguishing their faint reflected or emitted light from that of their host stars.Direct imaging addresses this challenge by suppressing the star's light to reveal the orbiting exoplanet.There are two approaches to direct imaging: internal occulters, called coronagraphs, which use optics within the telescope to block starlight; and external occulters, called starshades, which are petal-shaped masks spanning tens of meters in diameter, flown in tandem with a telescope (Arenberg et al., 2021).Current direct imaging efforts using ground-based coronagraphs at the Very Large Telescope (VLT) and at the Gemini Observatory have successfully imaged young, massive exoplanets at wide separations (Follette, 2023).However, observing a faint, Earth-like planet in the habitable zone of a Sun-like star requires extreme starlight suppression to the level of 10 8 -10 10 star-to-planet flux ratio (Angel et al., 1986).