  HISPEC (High-resolution Infrared Spectrograph for Exoplanet Characterization)
is a proposed diffraction-limited spectrograph for the W.M. Keck Observatory,
and a pathfinder for the MODHIS facility project (Multi-Object
Diffraction-limited High-resolution Infrared Spectrograph) on the Thirty Meter
Telescope. HISPEC/MODHIS builds on diffraction-limited spectrograph designs
which rely on adaptively corrected single-mode fiber feeds. Seeing-limited
high-resolution spectrographs, by virtue of the conservation of beam etendue,
grow in volume following a D^3 power law (D is the telescope diameter), and are
subject to daunting challenges associated with their large size.
Diffraction-limited spectrographs fed by single mode fibers are decoupled from
the telescope input, and are orders of magnitude more compact and have
intrinsically stable line spread functions. Their efficiency is directly
proportional to the performance of the adaptive optics (AO) system. AO
technologies have matured rapidly over the past two decades and are baselined
for future extremely large telescopes. HISPEC/MODHIS will take R>100,000
spectra of a few objects in a 10" field-of-view sampled at the diffraction
limit (~10-50 mas), simultaneously from 0.95 to 2.4 microns (y-K). The
scientific scope ranges from exoplanet infrared precision radial velocities,
spectroscopy of transiting, close-in, and directly imaged exoplanets
(atmospheric composition and dynamics, RM effect, spin measurements, Doppler
imaging), brown dwarf characterization, stellar physics/chemistry,
proto-planetary disk kinematics/composition, Solar system, extragalactic
science, and cosmology. HISPEC/MODHIS features a compact, cost-effective design
optimized to fully exploit the existing Keck-AO and future TMT-NFIRAOS
infrastructures and boost the scientific reach of Keck Observatory and TMT soon
after first light.
