RETIRED 2025B · KECK II · MAUNAKEA

KPIC

The Keck Planet Imager and Characterizer, 2018–2025

KPIC linked the Keck II adaptive optics system to the NIRSPEC high-resolution infrared spectrograph through a bundle of four single-mode fibers — the first fiber-fed high-dispersion coronagraph on a 10-m telescope. Placing a fiber on a planet and leaving the star behind, it turned faint points of light into spectra: molecules, radial velocities, and spins. Retired after seven years on sky, its science stands and its technology lives on in HISPEC and MODHIS.

R ≈ 35,000RESOLVING POWER
K + LFIRST-LIGHT BANDS · + y J H LATER
4 × SMFFIBER BUNDLE · 800 MAS
55+REFEREED PAPERS
UNSUPPRESSED STARLIGHTthe companion sits below the stellar residuals· tap, click, or select a stage
OFFICIALLY RETIRED

KPIC was decommissioned at the end of semester 2025B and is no longer offered for observing at W. M. Keck Observatory. This page preserves its scientific record, technology heritage, and facility documentation for legacy purposes.

2018–2025B

Seven years on the summit

Deployed at Keck II in September 2018 and commissioned in 2019, KPIC was built as a pathfinder: prove that single-mode fibers — with their stable line-spread function, diffraction-limited 50-mas acceptance, and fierce rejection of sky and starlight — could carry high-contrast targets into a high-resolution spectrograph. It worked, and then it kept working: two major upgrade campaigns, community access, 55+ refereed papers, and a design that became the template for its facility-class successors.

2018Fiber injection unit deployed at Keck II
2019Commissioned; first R > 30,000 spectra of imaged companions
2022Phase II: 1000-actuator DM, beam shaping, vortex mask
2024Phase III: y band, ADC, laser frequency combs; direct spectroscopy offered community-wide
2025BOfficially retired; architecture passes to HISPEC and MODHIS

SCIENCE ACCOMPLISHMENTS

What KPIC found

Five results from a 55+ paper record — and the archive is still publishing. The complete bibliography is collected in the KPIC ADS library.

FIRST SCIENCE · HR 8799

Molecules and motions of a four-planet system

KPIC resolved water and carbon monoxide in the atmospheres of the HR 8799 planets and measured their orbital radial velocities directly — spectroscopy of a multi-planet system that imaging alone could never deliver.

SPINS

Days comparable to Jupiter's ten hours

Rotationally broadened lines gave the spins of HR 8799 d and e — young super-Jupiters turning fast, a first clock on angular momentum in a directly imaged planetary system.

FORMATION TRACERS

Isotopes as birth certificates

Surveys of benchmark companions measured carbon-to-oxygen ratios, metallicities, and isotopologue ratios — the relative abundance of 13CO to 12CO — separating objects born like planets from those born like stars.

PROTOPLANETS

The chemistry of a world still forming

KPIC captured PDS 70 b mid-assembly, finding a stellar-like carbon-to-oxygen ratio in a planet still accreting from its natal disk — a direct constraint on where and how giant planets take on their gas.

2026 · CAPSTONE SURVEY

Giant planets and brown dwarfs spin down differently

KPIC's final spin survey compared rotation across dozens of companions, revealing distinct rotational evolution for giant planets and brown dwarfs — a population-level result published after retirement, from data the instrument left behind, and the opening question of the science program HISPEC inherits.

TECHNOLOGY PATHFINDING

What KPIC proved

KPIC was as much a technology demonstrator as an observatory workhorse: a series of agile, phased upgrades that retired risk for the facility-class instruments now in build — HISPEC at Keck and MODHIS at TMT both trace their fiber-fed architecture directly to it.

SINGLE-MODE FIBER INJECTION

High-dispersion coronagraphy at 10-m scale

The first on-sky proof that diffraction-limited single-mode fibers can couple faint companions from a high-contrast AO system into a high-resolution spectrograph — the founding demonstration of the HDC architecture.

INFRARED PYRAMID WFS

Wavefront sensing on red and faint stars

KPIC's infrared pyramid wavefront sensor, built on an e-APD array, extended sharp adaptive optics correction to cool, red, and optically faint hosts — opening M dwarfs and embedded young stars to high-contrast work.

VORTEX FIBER NULLING

Inside the diffraction limit

The first on-sky demonstration of fiber nulling, an interferometric mode that cancels the star within a single aperture to reach companions at and below one resolution element.

LASER FREQUENCY COMB

Precision calibration for the infrared

Laser frequency comb light fed through the KPIC fibers gave NIRSPEC an absolute wavelength ruler — the calibration infrastructure that precision radial velocity work on HISPEC will depend on.

ARCHIVE

Final observing modes

The configuration as last offered, in semester 2024B. All modes fed NIRSPEC at R ≈ 35,000. KPIC saw first light in the K and L bands and was later extended down to y, J, and H; the K band used a dedicated filter covering 1.952–2.501 µm. Archived for reference — no mode remains available.

MODEBANDSFINAL STATUS · 2024B
On-axis direct spectroscopy y · J · H · K K OFFERED  y J H · PI
Off-axis direct spectroscopy y · J · H · K K OFFERED  y J H · PI
Fiber nulling K · charge 1 & 2 PI
Laser frequency comb H PI

OFFERED = was TAC-allocatable (incl. NASA Keck time) · PI = KPIC-team mode · historical record

LEGACY DOCUMENTATION

Facility documents & data

The complete set of KPIC facility documents, preserved for legacy purposes — a reference for past users working with archival data and for instrument builders studying the design. The data reduction pipeline remains open-source and maintained on GitHub.

PDFProposal instructions 7 AUG 2024 PDFTechnical description 2 AUG 2024 PDFDaytime calibration procedure 5 NOV 2025 PDFCalibration source scheme 7 AUG 2024 PDFNighttime observing instructions 3 MAR 2025 PDFTroubleshooting guide 25 FEB 2025 GITData reduction pipeline — kpicteam/kpic_pipeline GITHUB ADSKPIC publication library — 55+ refereed papers NASA ADS