High contrast observations of bright stars with a starshade

Abstract

Starshades are a leading technology to enable the direct detection and spectroscopic characterization of Earth-like exoplanets. In an effort to advance starshade technology through system level demonstrations, the McMath-Pierce Solar Telescope was adapted to enable the suppression of astronomical sources with a starshade. The long baselines achievable with the heliostat provide measurements of starshade performance at a flight-like Fresnel number and resolution, aspects critical to the validation of optical models. The heliostat has provided the opportunity to perform the first astronomical observations with a starshade and has made science accessible in a unique parameter space, high contrast at moderate inner working angles. On-sky images are valuable for developing the experience and tools needed to extract science results from future starshade observations. We report on high contrast observations of nearby stars provided by a starshade. We achieve 5.6 × 10 −7 contrast at 30 arcseconds inner working angle on the star Vega and provide new photometric constraints on background stars near Vega.

Special Section on Starshades: Overview and a Dialogue

“…Starshades have been tested over kilometers of separation on dry lakebeds [34][35][36] and with a heliostat on Kitt Peak. 37,38 Similarly, the optical experiments of Harness et al were conducted in air.…”

Formation Design of Distributed Telescopes in Earth Orbit for Astrophysics Applications

“…Design and analysis techniques for these starshades have been studied extensively for the past 15 years. Indeed, previous authors have studied small-scale starshade designs for laboratory experiments [38], large-scale designs for survey missions to image Earth analogs [3,27,39], and scaling relations using scalar Fresnel theory [40,41]. However, previous authors have largely ignored one-tenth scale (several-meter diameter) starshades because they are simultaneously too large for ground-based experiments and too small for Earth analog imaging missions.…”

Imaging and Characterization of Extrasolar Planets with the Next Generation of Space Telescopes

“…Testing of scale models in the laboratory have proven the robustness of the basic concept [21]. Optical tests in ground-based facilities have been run in the McMath-Pierce Solar Telescope [21,22]. A 24 cm diameter starshade was set at a distance of 2.4 km; a dynamic range of 2 × 10 6 at 30 arcsec IWA on Vega was achieved [21].…”

“…The technology for starshade deployment, alignment, and operation in space is under development. Starshade prototypes are being constructed at the Jet Propulsion Laboratory [22] and proposed to be flown with the Habitable Exoplanets Observatory (Habex) [23].…”