NASA Insignia

Exoplanets

ORCAS will enable four key exoplanet science cases. ORCAS:

  • characterize approximately eight known exoplanets from radial velocities (RVs), astrometry, ground-based direct-imaging, and other techniques.
  • enable a deeper sensitivity to the zodi levels of approximately eight nearby stars and search for exoplanets around these stars as important precursor studies for a future flagship direct imaging mission such as HabEx or LUVOIR, including the "Deep Dive" HabEx targets.
  • uncover the planet formation process in disks around approximately eight young, nearby stars.
  • help us constrain the occurrence rates of cool sub-Jovian and super-Neptune exoplanets orbiting approximately a half-dozen nearby cool stars and brown dwarfs, as a precursor to the TMT/ELT era of imaging Habitable Zone M dwarf terrestrial exoplanets.
Simulated 650 nm R-band sensitivity contrast curves with ORCAS (green curve) and without ORCAS (HAKA concept, blue curve).
Simulated 650 nm R-band sensitivity contrast curves with ORCAS (green curve) and without ORCAS (HAKA concept, blue curve). HAKA is a conceptual visible imager coupled with a HODM natural guide star adaptive optics system on Keck Observatory. A wavelength-scaled approximate sensitivity from the current Keck Observatory NGSAO performance with NIRC2 at K-band is shown as the black segmented line. Shown in circles are approximate contrasts for Jovian planets orbiting a 30 Myr fifth magnitude host star. Contrast curves for MAVIS, planned for commissioning in 2027, would be intermediate between the projected performance of HAKA and a visible NIRC2-like imager.

Science Objectives:

Directly image exoplanets and disks around nearby stars.

Observable and Measurements:

Determine the presence of and characterize exoplanets and disks orbiting nearby stars through high-contrast adaptive optics imaging and low-resolution integral field spectroscopy.

Key Functional Requirements:

Visible (0.5 - 1.0 µm) and Near-Infrared (1 - 2.5 µm) imagers and integral field spectrographs (R ~ 50) with high-order deformable mirror (HODM) adaptive optics, illuminated by the ORCAS laser guide star.

ORCAS Uniqueness:

ORCAS will enable flux contrast improvements not obtainable for most nearby stars. For nearby bright stars of approximately fifth magnitude at visual wavelengths, ORCAS will provide approximately a one magnitude sensitivity improvement with HODM by providing more photons for adaptive optics corrections than available from the host star, equivalent to a zeroth magnitude guide star. For nearby stars fainter than fifth magnitude, ORCAS will enable imaging with the equivalent of a zeroth magnitude natural guide star adaptive optics (NGSAO), offering superior sensitivity compared to LGSAO by several orders of magnitude.