activity
20232026
most citedFour-of-a-kind? Comprehensive atmospheric characterisation of the HR 8799 planets with VLTI/GRAVITY

54 citations · 154 across the 20 of their papers we have counts for

collaborators

21 papers

astro-ph.EP2026

A first look at the protoplanet WISPIT 2 b with VLTI/GRAVITY+

GRAVITY+ Collaboration, K. Abd El Dayem, R. Abuter +116

Confirmed observations of young protoplanets actively undergoing the process of formation have remained rare to date. In this Letter, we present new insights into the nature of the…

astro-ph.EP2026

Spinning out of focus: The challenge of rotational line broadening in exoplanet reflection spectroscopy

T. O. Winterhalder, K. Molaverdikhani, D. Cont +17

Detecting light reflected off the dayside of an exoplanet in high-resolution spectroscopic data has proved to be a notoriously difficult endeavour. Despite several attempts, the fa…

astro-ph.IM2026

Exoplanet atmospheres and demographics in the 2040s

Jens Kammerer, Sydney Vach, Sylvestre Lacour +7

Direct observations of exoplanets probe the demographics and atmospheric composition of young self-luminous companions, yielding insight into their formation and early evolution hi…

astro-ph.IM2025

Hunting exomoons with a kilometric baseline interferometer

Thomas O. Winterhalder, Antoine Mérand, Sylvestre Lacour +3

Despite numerous search campaigns based on a diverse set of observational techniques, exomoons - prospective satellites of extrasolar planets - remain an elusive and hard-to-pin-do…

astro-ph.EP2025★ 8 cited

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★ 6 cited

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.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.EP2025★ 5 cited

Astrometric exomoon detection by means of optical interferometry

T. O. Winterhalder, A. Mérand, J. Kammerer +12

Context: With no conclusive detection to date, the search for exomoons, satellites of planets orbiting other stars, remains a formidable challenge. Detecting these objects, compili…

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.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.SR2025

On the Orbit of the Binary Brown Dwarf Companion GL229 Ba and Bb

William Thompson, Dori Blakely, Jerry W. Xuan +21

The companion GL229B was recently resolved by Xuan et al. (2024) as a tight binary of two brown dwarfs (Ba and Bb) through VLTI-GRAVITY interferometry and VLT-CRIRES+ RV measuremen…

astro-ph.EP2024

VLTI/GRAVITY Observations of AF Lep b: Preference for Circular Orbits, Cloudy Atmospheres, and a Moderately Enhanced Metallicity

William O. Balmer, Kyle Franson, Antoine Chomez +26

Direct imaging observations are biased towards wide-separation, massive companions that have degenerate formation histories. Although the majority of exoplanets are expected to for…

astro-ph.SR2024★ 29 cited

The cool brown dwarf Gliese 229 B is a close binary

Jerry W. Xuan, A. Mérand, W. Thompson +76

Owing to their similarities with giant exoplanets, brown dwarf companions of stars provide insights into the fundamental processes of planet formation and evolution. From their orb…

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.EP2024★ 54 cited

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.EP2024★ 16 cited

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.IM2024★ 10 cited

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.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.SR2023★ 15 cited

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.EP2023★ 11 cited

In-situ detection of Europa's water plumes is harder than previously thought

Rowan Dayton-Oxland, Hans L. F. Huybrighs, Thomas O. Winterhalder +2

Europa's subsurface ocean is a potential candidate for life in the outer solar system. It is thought that plumes may exist which eject ocean material out into space, which may be d…