papers

Publications (42)

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.GA2023

GOALS-JWST: Small neutral grains and enhanced 3.3 micron PAH emission in the Seyfert galaxy NGC 7469

Thomas S. -Y. Lai, Lee Armus, Marina Bianchin +36

We present James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) integral-field spectroscopy of the nearby luminous infrared galaxy, NGC 7469. We take advantage of…

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.EP2026

Limits on the Post-eclipse Emission Spectrum of HD 80606 b From High-Resolution Spectroscop

Luke Finnerty, Aurora Kesseli, Kyle Pearson +2

We present Keck/NIRSPEC -band observations of HD 80606 b, one of the most eccentric known exoplanets. HD 80606 b was observed after secondary eclipse, close to periastron, when…

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.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.EP2025

Velocity shift and SNR limits for high-resolution spectroscopy of hot Jupiters using Keck/KPIC

Kevin S. Hong, Luke Finnerty, Michael P. Fitzgerald

High-resolution cross-correlation spectroscopy (HRCCS) is a technique for detecting the atmospheres of close-in planets using the change in the projected planet velocity over a few…

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.GA2022

GOALS-JWST: Tracing AGN Feedback on the Star-Forming ISM in NGC 7469

Thomas S. -Y. Lai, Lee Armus, Vivian U +34

We present James Webb Space Telescope (JWST) Mid-InfraRed Instrument (MIRI) integral-field spectroscopy of the nearby merging, luminous infrared galaxy, NGC 7469. This galaxy hosts…

astro-ph.GA2022

Broad emission lines in optical spectra of hot dust-obscured galaxies can contribute significantly to JWST/NIRCam photometry

Jed McKinney, Luke Finnerty, Caitlin Casey +13

Selecting the first galaxies at z>7-10 from JWST surveys is complicated by z<6 contaminants with degenerate photometry. For example, strong optical nebular emission lines at z<6 ma…

astro-ph.IM2024

Keck Primary Mirror Closed-Loop Segment Control using a Vector-Zernike Wavefront Sensor

Maissa Salama, Charlotte Guthery, Vincent Chambouleyron +17

We present the first on-sky segmented primary mirror closed-loop piston control using a Zernike wavefront sensor (ZWFS) installed on the Keck II telescope. Segment co-phasing error…

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.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.EP2020

Simulating the Multi-Epoch Direct Detection Technique to Isolate the Thermal Emission of the Non-Transiting Hot Jupiter HD187123B

Cam Buzard, Luke Finnerty, Danielle Piskorz +7

We report the 6.5 detection of water from the hot Jupiter HD187123b with a Keplerian orbital velocity of 53 13 km/s. This high confidence detection is made using a…

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.GA2024

GOALS-JWST: Gas Dynamics and Excitation in NGC7469 revealed by NIRSpec

Marina Bianchin, Vivian U, Yiqing Song +36

We present new JWST-NIRSpec IFS data for the luminous infrared galaxy NGC7469: a nearby (70.6Mpc) active galaxy with a Sy 1.5 nucleus that drives a highly ionized gas outflow and a…

astro-ph.EP2025

An Early Look at the Performance of IGRINS-2 at Gemini-North with Application to the ultrahot Jupiter, WASP-33 b

Yeon-Ho Choi, Ueejeong Jeong, Jae-Joon Lee +56

Ground-based high-resolution spectroscopy enables precise molecular detections and velocity-resolved atmospheric dynamics, offering a distinct advantage over low-resolution methods…

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.GA2020

Fast Outflows in Hot Dust-Obscured Galaxies with Keck/NIRES

Luke Finnerty, Kirsten Larson, B. T. Soifer +10

We present rest-frame optical spectroscopic observations of 24 Hot Dust-Obscured Galaxies (Hot DOGs) at redshifts 1.7-4.6 with KECK/NIRES. Our targets are selected based on their e…

astro-ph.EP2020

Contrast and Temperature Dependence of Multi-Epoch High-Resolution Cross-Correlation Exoplanet Spectroscopy

Luke Finnerty, Cam Buzard, Stefan Pelletier +5

While high-resolution cross-correlation spectroscopy (HRCCS) techniques have proven effective at characterizing the atmospheres of transiting and non-transiting hot Jupiters, the l…

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.GA2022

GOALS-JWST: Resolving the Circumnuclear Gas Dynamics in NGC 7469 in the Mid-Infrared

Vivian U, Thomas Lai, Marina Bianchin +35

The nearby, luminous infrared galaxy (LIRG) NGC 7469 hosts a Seyfert nucleus with a circumnuclear star-forming ring and is thus the ideal local laboratory for investigating the sta…

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

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.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…