The path towards high-contrast imaging with the VLTI: the Hi-5 project

Abstract

The development of high-contrast capabilities has long been recognized as one of the top priorities for the VLTI. As of today, the VLTI routinely achieves contrasts of a few 10${}^{-3}$ in the near-infrared with PIONIER (H band) and GRAVITY (K band). Nulling interferometers in the northern hemisphere and non-redundant aperture masking experiments have, however, demonstrated that contrasts of at least a few 10${}^{-4}$ are within reach using specific beam combination and data acquisition techniques. In this paper, we explore the possibility to reach similar or higher contrasts on the VLTI. After reviewing the state-of-the-art in high-contrast infrared interferometry, we discuss key features that made the success of other high-contrast interferometric instruments (e.g., integrated optics, nulling, closure phase, and statistical data reduction) and address possible avenues to improve the contrast of the VLTI by at least one order of magnitude. In particular, we discuss the possibility to use integrated optics, proven in the near-infrared, in the thermal near-infrared (L and M bands, 3-5 $\mu$m), a sweet spot to image and characterize young extra-solar planetary systems. Finally, we address the science cases of a high-contrast VLTI imaging instrument and focus particularly on exoplanet science (young exoplanets, planet formation, and exozodiacal disks), stellar physics (fundamental parameters and multiplicity), and extragalactic astrophysics (active galactic nuclei and fundamental constants). Synergies and scientific preparation for other potential future instruments such as the Planet Formation Imager are also briefly discussed.

24 pages, 2 figures, accepted for publication in Experimental Astronomy

References in corpus (27)

• Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
• Circumstellar material in the Vega inner system revealed by CHARA/FLUOR
• Mid-infrared interferometry of 23 AGN tori: On the significance of polar-elongated emission
• A near-infrared interferometric survey of debris-disc stars. IV. An unbiased sample of 92 southern stars observed in H-band with VLTI/PIONIER
• A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC 4151
• A near-infrared interferometric survey of debris-disc stars. V. PIONIER search for variability
• The HOSTS survey - Exozodiacal dust measurements for 30 stars
• Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer
• Improving Interferometric Null Depth Measurements using Statistical Distributions: Theory and First Results with the Palomar Fiber Nuller
• First-light LBT nulling interferometric observations: warm exozodiacal dust resolved within a few AU of eta Corvi
• Progress in Modeling Very Low Mass Stars, Brown Dwarfs, and Planetary Mass Objects
• Ultrafast laser inscription of mid-IR directional couplers for stellar interferometry
• Astrointerferometry with discrete optics
• Integrated optics prototype beam combiner for long baseline interferometry in the L and M bands
• Hot circumstellar material resolved around beta Pic with VLTI/PIONIER
• Kernel-nulling for a robust direct interferometric detection of extrasolar planets
• An image-plane algorithm for JWST's non-redundant aperture mask data
• High-performance 3D waveguide architecture for astronomical pupil-remapping interferometry
• Searching for faint companions with VLTI/PIONIER. II. 92 main sequence stars from the Exozodi survey
• Fabrication tolerant chalcogenide mid-infrared multimode interference coupler design with application for Bracewell nulling interferometry
• Detecting the Companions and Ellipsoidal Variations of RS CVn Primaries: II. omicron Draconis, a Candidate for Recent Low-Mass Companion Ingestion
• Architecture design study and technology roadmap for the Planet Formation Imager (PFI)
• Multiplicity of Galactic Cepheids from long-baseline interferometry~III. Sub-percent limits on the relative brightness of a close companion of $\delta$~Cephei
• Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer
• Search for substellar-mass companions and asymmetries in their parent discs
• Status of the Planet Formation Imager (PFI) concept
• An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status

Cited by in corpus (20)

• Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
• Large Interferometer For Exoplanets (LIFE): I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
• The HOSTS survey for exozodiacal dust: Observational results from the complete survey
• Atmospheric characterization of terrestrial exoplanets in the mid-infrared: biosignatures, habitability & diversity
• 2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
• Super-Earths and Earth-like Exoplanets
• Space-based infrared interferometry to study exoplanetary atmospheres
• Asgard/NOTT: L-band nulling interferometry at the VLTI I. Simulating the expected high-contrast performance
• A near-infrared interferometric survey of debris-disk stars. VII. The hot/warm dust connection
• Increasing the achievable contrast of infrared interferometry with an error correlation model
• The Likelihood of Detecting Young Giant Planets with High Contrast Imaging and Interferometry
• GRAVITY for MATISSE -- Improving the MATISSE performance with the GRAVITY fringe tracker
• Prospects for the characterisation of exo-zodiacal dust with the VLTI
• How much large dust could be present in hot exozodiacal dust systems?
• Constraints on Planets in Nearby Young Moving Groups Detectable by High-Contrast Imaging and Gaia Astrometry
• Perspectives of a visible instrument on the VLTI
• High-contrast detection of exoplanets with a kernel-nuller at the VLTI
• Towards a Better Understanding of OPD Limitations for Higher Sensitivity and Contrast at the VLTI
• Photonics-based mid-infrared interferometry: 4-year results of the ALSI project and future prospects
• Asgard/NOTT: water vapor and CO${}_2$ atmospheric dispersion compensation system