Composition and thermal properties of Ganymede's surface from JWST/NIRSpec and MIRI observations

Context. We present the first spectroscopic observations of Ganymede by the James Webb Space Telescope undertaken in August 2022 as part of the proposal "ERS observations of the Jovian system as a demonstration of JWST's capabilities for Solar System science". Aims. We aimed to investigate the composition and thermal properties of the surface...

The spectroastrometric detectability of nearby Solar System-like exomoons

Context. Though efforts to detect them have been made with a variety of methods, no technique can claim a successful, confirmed detection of a moon outside the Solar System yet. Moon detection methods are restricted in capability to detecting moons of masses beyond what formation models would suggest, or they require surface temperatures...

Gaia Data Release 3: Stellar multiplicity, a teaser for the hidden treasure

Context. The Gaia DR3 catalogue contains, for the first time, about 800 000 solutions with either orbital elements or trend parameters for astrometric, spectroscopic, and eclipsing binaries, and combinations of these three.<br/><br/>Aims. With this paper, we aim to illustrate the huge potential of this large non-single-star catalogue.<br/><br/...

Tidally heated exomoons around Ïμ Eridani b: Observability and prospects for characterization

Context. Exomoons are expected to orbit gas giant exoplanets just as moons orbit Solar System planets. Tidal heating is present in Solar System satellites, and it can heat up their interior, depending on their orbital and interior properties. Aims. We aim to identify a tidally heated exomoon's (THEM) orbital parameter space that would make it...

Observing circumplanetary disks with METIS

Context. Gaining a full understanding of the planet and moon formation process calls for observations that probe the circumplanetary environment of accreting giant planets. The mid-infrared ELT imager and spectrograph (METIS) will provide a unique capability to detect warm-gas emission lines from circumplanetary disks. Aims. We aim to...

Neural Networks for Exoplanet Cartography

By the late 2020s or early 2030s, the next generation of telescopes will be able to directly observe the reflected starlight of Earth-like exoplanets. Because of the huge distance to other stars, such exoplanets will appear as single unresolved pixels. A single pixel can, however, provide information about what the planet looks like because its...

First ALMA Millimeter-wavelength Maps of Jupiter, with a Multiwavelength Study of Convection

We obtained the first maps of Jupiter at 1-3 mm wavelength with the Atacama Large Millimeter/Submillimeter Array (ALMA) on 2017 January 3-5, just days after an energetic eruption at 16.5S jovigraphic latitude had been reported by the amateur community, and about two to three months after the detection of similarly energetic eruptions in the...

Detecting proxima b's atmosphere with JWST targeting CO₂ at 15 μm using a high-pass spectral filtering technique

Exoplanet Proxima b will be an important laboratory for the search for extraterrestrial life for the decades ahead. Here, we discuss the prospects of detecting carbon dioxide at 15 μm using a spectral filtering technique with the Medium Resolution Spectrograph (MRS) mode of the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope ...

The O₂ A-Band in the Fluxes and Polarization of Starlight Reflected by Earth-Like Exoplanets

Earth-like, potentially habitable exoplanets are prime targets in the search for extraterrestrial life. Information about their atmospheres and surfaces can be derived by analyzing the light of the parent star reflected by the planet. We investigate the influence of the surface albedo A _s, the optical thickness b _cloud,...

Neptune’s zonal winds from near-IR Keck adaptive optics imaging in August 2001

We present H-band (1.4–1.8 ?m) images of Neptune with a spatial resolution of ?0.06?, taken with the W.M. Keck II telescope using the slit-viewing camera (SCAM) of the NIRSPEC instrument backed with Adaptive Optics. Images with 60-second integration times span 4 hours each on UT 20 and 21 August, 2001 and ?1 hour on UT 1 September, 2001. These...

Spectropolarimetric signatures of Earth-like extrasolar planets

We present results of numerical simulations of flux F and degree of polarization P of light that is reflected by Earth–like extrasolar planets orbiting solar type stars. Our results are presented as functions of the wavelength (from 0.3 to 1.0 ?m, with 0.001 ?m spectral resolution) and as functions of the planetary phase angle. We use different...