Engineering topics

Minardi, S.

Publications and source records attributed to Minardi, S..

3 records

NASA NTRS2018

Space-Based Infrared Interferometry to Study Exoplanetary Atmospheres

The quest for other habitable worlds and the search for life among them are major goals of modern astronomy. One way to make progress towards these goals is to obtain high-quality spectra of a large number of exoplanets over a broad range of wavelengths. While concepts currently investigated in the United States are focused on visible/NIR wavelengths, where the planets are probed in reflected light, a compelling alternative to characterize planetary atmospheres is the mid-infrared waveband (5-20 um). Indeed, mid-infrared observations provide key information on the presence of an atmosphere, the surface conditions (e.g., temperature, pressure, habitability), and the atmospheric composition in important species such as H2O,CO2, O3, CH4, and N2O. This information is essential to investigate the potential habitability of exoplanets and to make progress towards the search for life in the Universe. Obtaining high-quality mid-infrared spectra of exoplanets from the ground is however extremely challenging due to the overwhelming brightness and turbulence of the Earth's atmosphere. In this paper, we present a concept of space-based midinfrared interferometer that can tackle this observing challenge and discuss the maintechnological developments required to launch such a sophisticated instrument.

Defrère, D.↗

NASA NTRS2018

Hi-5: A Potential High-Contrast Thermal Near-Infrared Imager for the VLTI

Hi-5 is a high-contrast (or high dynamic range) infrared imager project for the VLTI. Its main goal is to characterize young extra-solar planetary systems and exozodiacal dust around southern main-sequence stars. In this paper, we present an update of the project and key technology pathways to improve the contrast achieved by the VLTI. 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 μm) and advanced fringe tracking strategies. We also address the strong exoplanet science case (young exoplanets, planet formation, and exozodiacal disks) offered by this wavelength regime as well as other possible science cases such as 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.

exozodiacal dust↗

NASA NTRS2018

The Path Towards High-Contrast Imaging with the VLTI: The Hi-5 Project

The development of high-contrast capabilities has long been recognized as one of the top priorities for the VLTI (Very Large Telescope Interferometer). As of today, the VLTI routinely achieves contrasts of a few 103 in the near-infrared with PIONIER (Precision Integrated-Optics Near-infrared Imaging ExpeRiment) (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 (sup -3) 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 microns), 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. This project is called Hi-5 for High-contrast Interferometry up to 5 microns.

PIONIER (H band)↗