High resolution Infrared Spectrograph for Exoplanet Characterization
HISPEC is a diffraction-limited, fiber-fed high-resolution infrared spectrograph covering the y to K band spectral range in one shot (0.95 to 2.5 microns). Being diffraction limited allows for a compact, stable and thus cost-effective design. HISPEC will be built for the Keck II telescope and fed by the KPIC fiber injection unit. HISPEC will be the workhorse high-resolution infrared spectrograph of TMT soon after first light, as part of the MODHIS facility, which includes a new fiber injection unit designed to integrate NFIRAOS the first light adaptive optics system of TMT. The scientific scope of HISPEC/MODHIS is very broad and ranges from exoplanet IR EPRV, transit spectroscopy, direct spectroscopy, BD characterization, stellar physics/chemistry, disk kinematics/composition, and extragalactic science.
| Parameters | Specifications | Notes |
| Wavelength coverage | y to K (0.95 to 2.5 microns) | Simultaneous |
| Resolving power (R) | 100,000 | On average |
| Instrumental stability | 30 cm/s | Goal: 10 cm/s, excludes atmosphere |
| Calibration | Laser Frequency Comb, Fabry-Perot Etalon | Gas cells for absolute reference |
| Design approach | Diffraction-limited | Single mode |
| Feed | Single-mode fibers, photonic lanterns | Modest multiplexing (TBD) |
| End-to-End efficiency | >5% | Goal: >10% |
| Sampling | >2.5 pixel | Over 80% of the range |
| Point Source sensitivity on Keck | 14-15 mag | S/N=30 per resel in 1 hour |
| Point Source sensitivity on TMT | 17-19 mag | S/N=30 per resel in 1 hour |
| Mode 1 | Single or multi-object | Photonic lantern or single-mode fibers |
| Mode 2 | High-contrast off-axis | High Dispersion Coronagraphy |
| Mode 3 | High-contrast on-axis | Vortex Fiber Nulling |