papers

Publications (47)

astro-ph.EP2021

Constraining the Nature of the PDS 70 Protoplanets with VLTI/GRAVITY

J. J. Wang, A. Vigan, S. Lacour +101

We present K-band interferometric observations of the PDS 70 protoplanets along with their host star using VLTI/GRAVITY. We obtained K-band spectra and 100 as precision astrome…

astro-ph.EP2020

Direct confirmation of the radial-velocity planet Pic c

M. Nowak, S. Lacour, A. -M. Lagrange +90

Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period,…

astro-ph.EP2020

Orbital and spectral characterization of the benchmark T-type brown dwarf HD 19467B

A. -L. Maire, K. Molaverdikhani, S. Desidera +42

Context. Detecting and characterizing substellar companions for which the luminosity, mass, and age can be determined independently is of utter importance to test and calibrate the…

astro-ph.EP2024

Four-of-a-kind? Comprehensive atmospheric characterisation of the HR 8799 planets with VLTI/GRAVITY

E. Nasedkin, P. Mollière, S. Lacour +95

With four companions at separations from 16 to 71 au, HR 8799 is a unique target for direct imaging, presenting an opportunity for the comparative study of exoplanets with a shared…

astro-ph.EP2019

First direct detection of an exoplanet by optical interferometry; Astrometry and K-band spectroscopy of HR8799 e

S. Lacour, M. Nowak, J. Wang +85

To date, infrared interferometry at best achieved contrast ratios of a few times on bright targets. GRAVITY, with its dual-field mode, is now capable of high contrast obs…

astro-ph.IM2022

Upgrading the high contrast imaging facility SPHERE: science drivers and instrument choices

A. Boccaletti, G. Chauvin, F. Wildi +71

SPHERE+ is a proposed upgrade of the SPHERE instrument at the VLT, which is intended to boost the current performances of detection and characterization for exoplanets and disks. S…

astro-ph.EP2019

VLT/SPHERE exploration of the young multiplanetary system PDS70

D. Mesa, M. Keppler, F. Cantalloube +51

Context. PDS 70 is a young (5.4 Myr), nearby (~113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) al…

astro-ph.SR2023

VLTI/GRAVITY Observations and Characterization of the Brown Dwarf Companion HD 72946 B

W. O. Balmer, L. Pueyo, T. Stolker +96

Tension remains between the observed and modeled properties of substellar objects, but objects in binary orbits, with known dynamical masses can provide a way forward. HD 72946 B i…

astro-ph.EP2024

A new treatment of telluric and stellar features for medium resolution spectroscopy and molecular mapping. Application to the abundance determination on Beta Pic b

F. Kiefer, M. Bonnefoy, B. Charnay +5

Molecular mapping is a supervised method exploiting the spectral diversity of integral field spectrographs to detect and characterize resolved exoplanets blurred into the stellar h…

astro-ph.EP2018

Spectral and orbital characterisation of the directly imaged giant planet HIP 65426 b

A. C. Cheetham, M. Samland, S. S. Brems +38

HIP 65426 b is a recently discovered exoplanet imaged during the course of the SPHERE-SHINE survey. Here we present new and observations of the planet from the NACO instr…

astro-ph.EP2018

Post conjunction detection of Pictoris b with VLT/SPHERE

A. -M. Lagrange, A. Boccaletti, M. Langlois +102

With an orbital distance comparable to that of Saturn in the solar system, \bpic b is the closest (semi-major axis \,9\,au) exoplanet that has been imaged to orbit a star.…

astro-ph.EP2026

A Panchromatic JWST Spectrum of a Giant Starspot on the Fully Convective M-dwarf TOI-3884

C. A. Murray, L. Garcia, B. V. Rackham +18

TOI-3884 b is a rare super-Neptune transiting a fully convective M dwarf that hosts a persistent giant polar spot. Because the planet occults this active region during every transi…

astro-ph.IM2024

High contrast at short separation with VLTI/GRAVITY: Bringing Gaia companions to light

N. Pourré, T. O. Winterhalder, J. -B. Le Bouquin +173

Since 2019, GRAVITY has provided direct observations of giant planets and brown dwarfs at separations of down to 95 mas from the host star. Some of these observations have provided…

astro-ph.EP2018

The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data

M. Bonnefoy, K. Perraut, A. -M. Lagrange +79

The G-type star GJ504A is known to host a 3 to 35 MJup companion whose temperature, mass, and projected separation all contribute to make it a test case for the planet formation th…

astro-ph.EP2025

A JWST/MIRI view of k Andromedae b: Refining its mass, age, and physical parameters

N. Godoy, E. Choquet, E. Serabyn +7

Context. kAndb is a substellar companion near the planet-brown dwarf boundary, orbiting a B9IV star at 50-100 au. Estimates of its age and mass vary, fueling a decade-long debate.…

astro-ph.EP2021

Near-infrared transmission spectrum of TRAPPIST-1 h using Hubble WFC3 G141 observations

A. Gressier, M. Mori, Q. Changeat +4

The TRAPPIST-1 planetary system is favourable for transmission spectroscopy and offers the unique opportunity to study rocky planets with possibly non-primary envelopes. We present…

astro-ph.SR2017

In-depth study of moderately young but extremely red, very dusty substellar companion HD206893B

P. Delorme, T. Schmidt, M. Bonnefoy +47

The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate the atypical properties o…

astro-ph.EP2025

Evidence for a sub-jovian planet in the young TWA7 disk

A. -M. Lagrange, C. Wilkinson, M. Mâlin +26

Planets are thought to form from dust and gas in protoplanetary disks, and debris disks are the remnants of planet formation. Aged a few Myr up to a few Gyr, debris disks have lost…

astro-ph.EP2023

Direct discovery of the inner exoplanet in the HD206893 system. Evidence for deuterium burning in a planetary-mass companion

S. Hinkley, S. Lacour, G. -D. Marleau +110

Long term precise radial velocity (RV) monitoring of the nearby star HD206893, as well as anomalies in the system proper motion, have suggested the presence of an additional, inner…

astro-ph.EP2020

SPHERE+: Imaging young Jupiters down to the snowline

A. Boccaletti, G. Chauvin, D. Mouillet +130

SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years, demonstrating a high level of performance. SPHERE has produced outstanding results using a…

astro-ph.EP2026

The ExoGRAVITY survey: A K-band spectral library of giant exoplanet and brown dwarf companions

J. Kammerer, T. O. Winterhalder, S. Lacour +106

Direct observations of exoplanet and brown dwarf companions with near-infrared interferometry, first enabled by the dual-field mode of VLTI/GRAVITY, provide unique measurements of…

astro-ph.IM2024

A catalogue of dual-field interferometric binary calibrators

M. Nowak, S. Lacour, R. Abuter +97

Dual-field interferometric observations with VLTI/GRAVITY sometimes require the use of a "binary calibrator", a binary star whose individual components remain unresolved by the int…

astro-ph.EP2023

ATMOSPHERIX: I- An open source high resolution transmission spectroscopy pipeline for exoplanets atmospheres with SPIRou

B. Klein, F. Debras, J. -F. Donati +28

Atmospheric characterisation of exoplanets from the ground is an actively growing field of research. In this context we have created the ATMOSPHERIX consortium: a research project…

astro-ph.EP2025

The planetary-mass-limit VLT/SINFONI library: Spectral extraction and atmospheric characterization via forward modeling

P. Palma-Bifani, M. Bonnefoy, G. Chauvin +9

We aim to deepen our understanding of the M-L transition on planetary-mass companions and isolated brown dwarfs, and search for evidence of possible differences between these two p…

astro-ph.EP2025

Exomoon search with VLTI/GRAVITY around the substellar companion HD 206893 B

Q. Kral, J. Wang, J. Kammerer +130

Direct astrometric detection of exomoons remains unexplored. This study presents the first application of high-precision astrometry to search for exomoons around substellar compani…

astro-ph.EP2025

Characterization of AF Lep b at high spectral resolution with VLT/HiRISE

A. Denis, A. Vigan, J. Costes +41

Since the recent discovery of the directly imaged super-Jovian planet AF Lep b, several studies have been conducted to characterize its atmosphere and constrain its orbital paramet…

astro-ph.EP2025

Direct imaging discovery of a young giant planet orbiting on Solar System scales

T. Stolker, M. Samland, L. B. F. M. Waters +102

HD 135344 AB is a young visual binary system that is best known for the protoplanetary disk around the secondary star. The circumstellar environment of the A0-type primary star, on…

astro-ph.EP2021

The mass of Beta Pictoris c from Beta Pictoris b orbital motion

S. Lacour, J. J. Wang, L. Rodet +96

We aim to demonstrate that the presence and mass of an exoplanet can now be effectively derived from the astrometry of another exoplanet. We combined previous astrometry of Pi…

astro-ph.EP2024

Probing atmospheric escape through metastable He I triplet lines in 15 exoplanets observed with SPIRou

A. Masson, S. Vinatier, B. Bézard +23

For several years, the metastable helium triplet line has been successfully used as a tracer to probe atmospheric escape in transiting exoplanets. This absorption in the near-infra…

astro-ph.EP2025

Multi-modal atmospheric characterization of Pictoris b: Adding high-resolution continuum spectra from GRAVITY

M. Ravet, M. Bonnefoy, G. Chauvin +24

We present the first VLTI/GRAVITY observations at R of Pic b. These four high S/N (20) K-band spectra conserve both the pseudo-continuum and molecular abso…

astro-ph.EP2019

Peering into the formation history of beta Pictoris b with VLTI/GRAVITY long baseline interferometry

GRAVITY Collaboration, M. Nowak, S. Lacour +65

Our objective is to estimate the C/O ratio in the atmosphere of beta Pictoris b and obtain an estimate of the dynamical mass of the planet, as well as to refine its orbital paramet…

astro-ph.EP2017

New spectro-photometric characterization of the substellar object HR 2562 B using SPHERE

D. Mesa, J. -L. Baudino, B. Charnay +32

HR2562 is an F5V star located at ~33 pc from the Sun hosting a substellar companion that was discovered using the GPI instrument. The main objective of the present paper is to prov…

astro-ph.SR2023

VLTI/GRAVITY Provides Evidence the Young, Substellar Companion HD 136164 Ab formed like a "Failed Star"

William O. Balmer, L. Pueyo, S. Lacour +93

Young, low-mass Brown Dwarfs orbiting early-type stars, with low mass ratios (), appear intrinsically rare and present a formation dilemma: could a handful of these…

astro-ph.EP2023

First VLTI/GRAVITY Observations of HIP 65426 b: Evidence for a Low or Moderate Orbital Eccentricity

S. Blunt, W. O. Balmer, J. J. Wang +95

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In t…

astro-ph.EP2024

Atmospheric properties of AF Lep b with forward modeling

P. Palma-Bifani, G. Chauvin, D. Borja +11

Aims. We aim to expand the atmospheric exploration of AF Lep b by modeling all available observations obtained with SPHERE at VLT (between 0.95-1.65, at 2.105, and 2.253 m, and…

astro-ph.EP2020

Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e

P. Mollière, T. Stolker, S. Lacour +25

Clouds are ubiquitous in exoplanet atmospheres and represent a challenge for the model interpretation of their spectra. Complex cloud models are too numerically costly for generati…

astro-ph.EP2018

Orbital and atmospheric characterization of the planet within the gap of the PDS 70 transition disk

A. Müller, M. Keppler, Th. Henning +43

Aims: We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in the course of the SHINE survey with SPHERE, the extreme a…

astro-ph.EP2021

GRAVITY K-band spectroscopy of HD 206893 B: brown dwarf or exoplanet

J. Kammerer, S. Lacour, T. Stolker +94

We aim to reveal the nature of the reddest known substellar companion HD 206893 B by studying its near-infrared colors and spectral morphology and by investigating its orbital moti…

astro-ph.EP2012

Global modelling of the early Martian climate under a denser CO2 atmosphere: Water cycle and ice evolution

R. Wordsworth, F. Forget, E. Millour +3

We discuss 3D global simulations of the early Martian climate that we have performed assuming a faint young Sun and denser CO2 atmosphere. We include a self-consistent representati…

astro-ph.EP2023

Simulated performance of the molecular mapping for young giant exoplanets with the Medium Resolution Spectrometer of JWST/MIRI

M. Mâlin, A. Boccaletti, B. Charnay +2

Young giant planets are the best targets for characterization with direct imaging. The Medium Resolution Spectrometer (MRS) of the Mid-Infrared Instrument (MIRI) of the recently la…

astro-ph.EP2025

Constraints on the Orbit of the Young Substellar Companion GQ Lup B from High-Resolution Spectroscopy and VLTI/GRAVITY Astrometry

Vidya Venkatesan, S. Blunt, J. J. Wang +99

Understanding the orbits of giant planets is critical for testing planet formation models, particularly at wide separations greater than 10 au where traditional core accretion beco…

astro-ph.EP2017

Discovery of a warm, dusty giant planet around HIP65426

G. Chauvin, S. Desidera, A. -M. Lagrange +120

The SHINE program is a large high-contrast near-infrared survey of 600 young, nearby stars. It is aimed at searching for and characterizing new planetary systems using VLT/SPHERE's…

astro-ph.EP2023

Peering into the Young Planetary System AB Pic. Atmosphere, Orbit, Obliquity & Second Planetary Candidate

P. Palma-Bifani, G. Chauvin, M. Bonnefoy +24

We aim to revisit the system AB Pic which has a known companion at the exoplanet/ brown-dwarf boundary. We based this study on a rich set of observations to investigate the compani…

astro-ph.EP2024

Combining Gaia and GRAVITY: Characterising five new Directly Detected Substellar Companions

T. O. Winterhalder, S. Lacour, A. Mérand +96

Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how the combination of data obtained by Gaia and GRAVITY can help enlarg…

astro-ph.EP2025

Orbit and atmosphere of HIP 99770 b through the eyes of VLTI/GRAVITY

T. O. Winterhalder, J. Kammerer, S. Lacour +92

Context: Inferring the likely formation channel of giant exoplanets and brown dwarf companions from orbital and atmospheric observables remains a formidable challenge. Further and…

astro-ph.EP2021

The ExoGRAVITY project: using single mode interferometry to characterize exoplanets

S. Lacour, J. J. Wang, M. Nowak +89

Combining adaptive optics and interferometric observations results in a considerable contrast gain compared to single-telescope, extreme AO systems. Taking advantage of this, the E…

astro-ph.EP2023

ATMOSPHERIX: II- Characterising exoplanet atmospheres through transmission spectroscopy with SPIRou

F. Debras, B. Klein, J. -F. Donati +26

In a companion paper, we introduced a publicly-available pipeline to characterise exoplanet atmospheres through high-resolution spectroscopy. In this paper, we use this pipeline to…