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Gaia astrometry and exoplanetary science: DR2, (E)DR3, and beyond

Sozzetti, Alessandro

I review the recent impact of Gaia astrometry in the exoplanet field, both in terms of characterization of the orbits and masses of planetary systems and the properties of their host stars. I then discuss the newly published results in the third major data release (DR3), that begin to tackle exoplanetary science based on Gaia data alone. I conclud…

North Polar Spur/Loop I: gigantic outskirt of the Northern Fermi bubble or nearby hot gas cavity blown by supernovae?

Lallement, Rosine

Radio continuum, microwave and gamma-ray images of the Milky Way reveal a conspicuous, loop-like structure that fills almost half of the northern Galactic hemisphere, called Loop I. The interior of Loop I is shining in soft X-rays, and its eastern base is a bright, elongated structure dubbed the North Polar Spur (NPS). After 40 years of debates, t…

The MICROSCOPE space mission to test the Equivalence Principle

Métris, Gilles; Rodrigues, Manuel; Touboul, Pierre +2 more

Astronomical distance scales

Mignard, François

This article is an overview of the determination of astronomical distances from a metrological standpoint. Distances are considered from the Solar System (planetary distances) to extragalactic distances, with a special emphasis on the fundamental step of the trigonometric stellar distances and the giant leap recently experienced in this field than…

Comets at radio wavelengths

Bockelée-Morvan, Dominique; Biver, Nicolas; Crovisier, Jacques +1 more

Comets are considered as the most primitive objects in the Solar System. Their composition provides information on the composition of the primitive solar nebula, 4.6 Gyr ago. The radio domain is a privileged tool to study the composition of cometary ices. Observations of the OH radical at 18 cm wavelength allow us to measure the water production r…

A variety of radars designed to explore the hidden structures and properties of the Solar System's planets and bodies

Ciarletti, Valérie

Since the very first observations of the Moon from the Earth with radar in 1946, radars are more and more frequently selected to be part of the payload of exploration missions in the Solar System. They are, in fact, able to collect information on the surface structure of bodies or planets hidden by opaque atmospheres, to probe the planet subsurfac…

Observation and theoretical modeling of electron scale solar wind turbulence

Belmont, Gérard; Rezeau, Laurence; Sahraoui, Fouad +4 more

Turbulence at MagnetoHydroDynamics (MHD) scales in the solar wind has been studied for more than three decades, using data analysis, theoretical and numerical modeling. However, smaller scales have not been explored until very recently. Here, we review recent results on the first observation of cascade and dissipation of the solar wind turbulence …

High energy activity of the super-massive black hole at the Galactic Center

Goldwurm, Andrea

The center of our galaxy hosts the nearest super-massive black hole to the solar system, identified with the compact radio source Sgr A ^*. High energy experiments have tried in the past to detect the X/gamma-ray emission expected from the accretion of the surrounding material into this super-massive black hole. Only recently, however, t…

Metrology of angles in astronomy

Kovalevsky, Jean

In astronomy, measurements of angles play a major role. After defining the units in use in astronomy, three methods of measuring angles are presented, with an application to the transit instrument. The interferometric techniques for measuring large angles are described in optical and radio wavelengths. Due to the atmospheric and mechanical limitat…