papers

Publications (39)

astro-ph.EP2024

Atmospheric characterization of the super-Jupiter HIP 99770 b with KPIC

Yapeng Zhang, Jerry W. Xuan, Dimitri Mawet +28

Young, self-luminous super-Jovian companions discovered by direct imaging provide a challenging test of planet formation and evolution theories. By spectroscopically characterizing…

astro-ph.EP2023

Detecting exomoons from radial velocity measurements of self-luminous planets: application to observations of HR 7672 B and future prospects

Jean-Baptiste Ruffio, Katelyn Horstman, Dimitri Mawet +36

The detection of satellites around extrasolar planets, so called exomoons, remains a largely unexplored territory. In this work, we study the potential of detecting these elusive o…

astro-ph.EP2023

Keck/KPIC Emission Spectroscopy of WASP-33b

Luke Finnerty, Tobias Schofield, Ben Sappey +29

We present Keck/KPIC high-resolution () -band thermal emission spectroscopy of the ultra-hot Jupiter WASP-33b. The use of KPIC's single-mode fibers greatly improves…

astro-ph.IM2020

Detecting and characterizing close-in exoplanets with Vortex Fiber Nulling

Daniel Echeverri, Garreth Ruane, Benjamin Calvin +8

Vortex Fiber Nulling (VFN) is an interferometric method for suppressing starlight to detect and spectroscopically characterize exoplanets. It relies on a vortex phase mask and sing…

astro-ph.EP2025

Water dissociation and rotational broadening in the atmosphere of KELT-20 b from high-resolution spectroscopy

Luke Finnerty, Yinzi Xin, Jerry W. Xuan +29

We present atmospheric retrievals from Keck/KPIC phase II observations of the ultra-hot Jupiter KELT-20/MASCARA-2~b. Previous free retrievals of molecular abundances for ultra-hot…

astro-ph.EP2022

Retrieving the C and O Abundances of HR 7672~AB: a Solar-Type Primary Star with a Benchmark Brown Dwarf

Ji Wang, Jared R. Kolecki, Jean-Baptiste Ruffio +30

A benchmark brown dwarf (BD) is a BD whose properties (e.g., mass and chemical composition) are precisely and independently measured. Benchmark BDs are valuable in testing theoreti…

astro-ph.EP2025

The watery atmosphere of HD~209458~b revealed by joint - and -band high-resolution spectroscopy

Luke Finnerty, Julie Inglis, Michael P. Fitzgerald +26

We present a joint analysis of high-resolution - and -band observations of the benchmark hot Jupiter \hdb\ from the Keck Planet Imager and Characterizer (KPIC). One half nigh…

astro-ph.SR2024

Rotation and Abundances of the Benchmark Brown Dwarf HD 33632 Ab from Keck/KPIC High-resolution Spectroscopy

Chih-Chun Hsu, Jason J. Wang, Jerry W. Xuan +24

We present the projected rotational velocity and molecular abundances for HD 33632 Ab obtained via Keck Planet Imager and Characterizer high-resolution spectroscopy. HD 33632 Ab is…

astro-ph.EP2023

Atmospheric metallicity and C/O of HD 189733 b from high-resolution spectroscopy

Luke Finnerty, Jerry W. Xuan, Yinzi Xin +27

We present high-resolution -band emission spectra of the quintessential hot Jupiter HD 189733 b from the Keck Planet Imager and Characterizer (KPIC). Using a Bayesian retrieval…

astro-ph.EP2022

Retrieving C and O Abundance of HR 8799 c by Combining High- and Low-Resolution Data

Ji Wang, Jason J. Wang, Jean-Baptiste Ruffio +29

The formation and evolution pathway for the directly-imaged multi-planetary system HR 8799 remains mysterious. Accurate constraints on the chemical composition of the planetary atm…

astro-ph.EP2024

Vortex Fiber Nulling for Exoplanet Observations: First Direct Detection of M Dwarf Companions around HIP 21543, HIP 94666, and HIP 50319

Daniel Echeverri, Jerry W. Xuan, John D. Monnier +35

Vortex fiber nulling (VFN) is a technique for detecting and characterizing faint companions at small separations from their host star. A near-infrared (m) VFN demonstra…

astro-ph.EP2022

Phase II of the Keck Planet Imager and Characterizer: system-level laboratory characterization and preliminary on-sky commissioning

Daniel Echeverri, Nemanja Jovanovic, Jacques-Robert Delorme +35

The Keck Planet Imager and Characterizer (KPIC) is a series of upgrades for the Keck II Adaptive Optics (AO) system and the NIRSPEC spectrograph to enable diffraction-limited, high…

astro-ph.IM2024

The high-contrast performance of the Keck Planet Imager and Characterizer

Jason J. Wang, Dimitri Mawet, Jerry W. Xuan +25

The Keck Planet Imager and Characterizer (KPIC), a series of upgrades to the Keck II Adaptive Optics System and Instrument Suite, aims to demonstrate high-resolution spectroscopy o…

astro-ph.EP2025

Chemical and Isotopic Homogeneity Between the L Dwarf CD-35 2722 B and its Early M Host Star

Gavin Wang, Jerry Xuan, Darío Picos +29

CD-35 2722 B is an L dwarf companion to the nearby, Myr old M1 dwarf CD-35 2722 A. We present a detailed analysis of both objects using high-resolution ($R \sim 35,00…

astro-ph.EP2025

Fringing analysis and forward modeling of Keck Planet Imager and Characterizer (KPIC) spectra

Katelyn A. Horstman, Jean-Baptiste Ruffio, Jason J. Wang +27

The Keck Planet Imager and Characterizer (KPIC) combines high contrast imaging with high resolution spectroscopy (R~35,000 in K band) to study directly imaged exoplanets and brown…

astro-ph.IM2021

Enhancing Direct Exoplanet Spectroscopy with Apodizing and Beam Shaping Optics

Benjamin Calvin, Nemanja Jovanovic, Garreth Ruane +8

Direct exoplanet spectroscopy aims to measure the spectrum of an exoplanet while simultaneously minimizing the light collected from its host star. Isolating the planet light from t…

astro-ph.EP2021

Detection and Bulk Properties of the HR 8799 Planets with High Resolution Spectroscopy

Jason J. Wang, Jean-Baptiste Ruffio, Evan Morris +49

Using the Keck Planet Imager and Characterizer (KPIC), we obtained high-resolution (R35,000) -band spectra of the four planets orbiting HR 8799. We clearly detected \water…

astro-ph.IM2025

The Simultaneous Operation of a Controllable Segmented Primary Mirror and Single Conjugate Adaptive Optics System part 2 -- Simulated Operation

Benjamin Calvin, Michael Fitzgerald, Sam Ragland

There are scientific and technological needs to improve the co-phasing of the primary mirrors of segmented telescopes. We have developed a methodology for using the wavefront senso…

astro-ph.IM2019

Demonstration of an electric field conjugation algorithm for improved starlight rejection through a single mode optical fiber

Jorge Llop Sayson, Garreth Ruane, Dimitri Mawet +8

Linking a coronagraph instrument to a spectrograph via a single mode optical fiber is a pathway towards detailed characterization of exoplanet atmospheres with current and future g…

astro-ph.IM2021

The Keck Planet Imager and Characterizer: A dedicated single-mode fiber injection unit for high resolution exoplanet spectroscopy

Jacques-Robert Delorme, Nemanja Jovanovic, Daniel Echeverri +28

The Keck Planet Imager and Characterizer (KPIC) is a purpose-built instrument to demonstrate new technological and instrumental concepts initially developed for the exoplanet direc…

astro-ph.EP2024

A Survey of Protoplanetary Disks Using the Keck/NIRC2 Vortex Coronagraph

Nicole L. Wallack, Jean-Baptiste Ruffio, Garreth Ruane +34

Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations of protoplanetary disks in the millimeter continuum have shown a variety of radial gaps, cavities, and spira…

astro-ph.EP2024

kappa And b is a fast rotator from KPIC High Resolution Spectroscopy

Evan C. Morris, Jason J. Wang, Chih-Chun Hsu +24

We used the Keck Planet Imager and Characterizer (KPIC) to obtain high-resolution (R35,000) K-band spectra of kappa Andromedae b, a planetary-mass companion orbiting the B9V…

astro-ph.EP2025

Dynamical Architectures of S-type Transiting Planets in Binaries II: A Dichotomy in Orbital Alignment of Small Planets in Close Binary Systems

Jingwen Zhang, Daniel Huber, Michael Bottom +35

Stellar multiplicity plays a crucial role in shaping planet formation and dynamical evolution. We present a survey of 54 TESS Objects of Interest (TOIs) within 300 pc that exhibit…

astro-ph.EP2026

Atmospheric characterization of six ultra-hot Jupiters from -band high-resolution spectroscopy

Luke Finnerty, Michael P. Fitzgerald, Yinzi Xin +27

We present new Keck/KPIC high-resolution spectroscopic detections of three ultra-hot Jupiters (UHJs) in the band: WASP-189b (), MASCARA-1b (), and…

astro-ph.IM2025

The Santa Cruz Extreme AO Lab (SEAL) 2.0: A reflective, multi-wavelength rebuild

Rebecca Jensen-Clem, Vincent Chambouleyron, Prince Javier +20

The Santa cruz Extreme Adaptive optics Lab (SEAL) is a visible/near-infrared wavelength testbed designed to support technology development for high contrast imaging on large, segme…

astro-ph.EP2024

True mass and atmospheric composition of the non-transiting hot Jupiter HD 143105 b

Luke Finnerty, Yinzi Xin, Jerry W. Xuan +28

We present Keck/KPIC phase II -band observations of the non-transiting hot Jupiter HD 143105 b. Using a cross-correlation approach, we make the first detection of the planetary…

astro-ph.EP2026

Distinct Rotational Evolution of Giant Planets and Brown Dwarf Companions

Chih-Chun Hsu, Jason J. Wang, Jerry W. Xuan +27

We present a rotational velocity (vsini) survey of 32 stellar/substellar objects and giant planets using Keck/KPIC high-resolution spectroscopy, including 6 giant planets (2-7 M$_\…

astro-ph.EP2024

RV measurements of directly imaged brown dwarf GQ Lup B to search for exo-satellites

Katelyn Horstman, Jean-Baptiste Ruffio, Konstantin Batygin +35

GQ Lup B is one of the few substellar companions with a detected cicumplanetary disk, or CPD. Observations of the CPD suggest the presence of a cavity, possibly formed by an exo-sa…

astro-ph.EP2024

PDS 70b Shows Stellar-like Carbon-to-oxygen Ratio

Chih-Chun Hsu, Jason J. Wang, Geoffrey A. Blake +27

The 5 Myr PDS 70 is the only known system with protoplanets residing in the cavity of the circumstellar disk from which they formed, ideal for studying exoplanet formation an…

astro-ph.EP2026

Possible stratospheric emission in the warm Neptune GJ 436 b from high-resolution spectroscopy

Luke Finnerty, Michael P Fitzgerald, Jerry W Xuan +26

We present high spectral resolution band (2.91--3.85 m) observations of the warm Neptune GJ 436 b from Keck II/KPIC. KPIC's single-mode fiber feed reduces the band sky…

astro-ph.IM2025

The Simultaneous Operation of a Controllable Segmented Primary Mirror and Single Conjugate Adaptive Optics System part 1 -- Design Concept and Sensitivity Analysis

Benjamin Calvin, Michael Fitzgerald

The maintenance of primary mirror segment co-phasing is a critical aspect to the operation of segmented telescopes. However, speckle-based measurements of the phasing of the Keck p…

astro-ph.IM2025

Technical description and performance of the phase II version of the Keck Planet Imager and Characterizer

Nemanja Jovanovic, Daniel Echeverri, Jacques-Robert Delorme +46

The Keck Planet Imager and Characterizer (KPIC) is a series of upgrades for the Keck II Adaptive Optics (AO) system and the NIRSPEC spectrograph to enable diffraction limited, high…

astro-ph.EP2025

HD 206893 B at High Spectral Resolution with the Keck Planet Imager and Characterizer (KPIC)

Ben Sappey, Quinn Konopacky, Clarissa R. Do O +38

We present an atmospheric characterization and orbital analysis of HD 206893 B, an exceptionally red, L/T-transition substellar companion in a multiplanetary system, via Keck Plane…

astro-ph.SR2024

Orbital and Atmospheric Characterization of the 1RXS J034231.8+121622 System Using High-Resolution Spectroscopy Confirms That The Companion is a Low-Mass Star

Clarissa R. Do Ó, Ben Sappey, Quinn M. Konopacky +33

The 1RXS J034231.8+121622 system consists of an M dwarf primary and a directly imaged low-mass stellar companion. We use high resolution spectroscopic data from Keck/KPIC to estima…

astro-ph.EP2024

Are these planets or brown dwarfs? Broadly solar compositions from high-resolution atmospheric retrievals of ~10-30 companions

Jerry W. Xuan, Chih-Chun Hsu, Luke Finnerty +32

Using Keck Planet Imager and Characterizer (KPIC) high-resolution (~35000) spectroscopy from 2.29-2.49 m, we present uniform atmospheric retrievals for eight young substella…

astro-ph.SR2023

Validation of elemental and isotopic abundances in late-M spectral types with the benchmark HIP 55507 AB system

Jerry W. Xuan, Jason J. Wang, Luke Finnerty +48

M dwarfs are common host stars to exoplanets but often lack atmospheric abundance measurements. Late-M dwarfs are also good analogs to the youngest substellar companions, which sha…

astro-ph.IM2023

Vortex Fiber Nulling for Exoplanet Observations: Implementation and First Light

Daniel Echeverri, Jerry Xuan, Nemanja Jovanovic +31

Vortex fiber nulling (VFN) is a single-aperture interferometric technique for detecting and characterizing exoplanets separated from their host star by less than a diffracted beam…

astro-ph.IM2019

Status of the Keck Planet Imager and Characterizer Phase II Development

Jacklyn Pezzato, Nemanja Jovanovic, Dimitri Mawet +15

The Keck Planet Imager and Characterizer comprises of a series of upgrades to the Keck II adaptive optics system and instrument suite to improve the direct imaging and high resolut…

astro-ph.EP2022

A Clear View of a Cloudy Brown Dwarf Companion from High-Resolution Spectroscopy

Jerry W. Xuan, Jason Wang, Jean-Baptiste Ruffio +37

Direct imaging studies have mainly used low-resolution spectroscopy () to study the atmospheres of giant exoplanets and brown dwarf companions, but the presence of clo…