DELBO , M.

Context: Observation of star occultations is a powerful tool to determine shapes and sizes of asteroids. This is key information necessary for studying the evolution of the asteroid belt and to calibrate indirect methods of size determination, such as the models used to analyze thermal infrared observations. Up to now, the observation of...

Lunar impact flash (LIF) observations typically occur in R, I, or unfiltered light, and are only possible during night, targeting the night side of a 10-60% illumination Moon, while >10°above the observers horizon. This severely limits the potential to observe, and therefore the number of lower occurrence, high energy impacts observed is...

Context. Andesitic meteorites are among the oldest achondrites known to date. They record volcanic events and crust formation episodes in primordial planetesimals that took place about 4.565 Myr ago. However, no analogue for these meteorites has been found in the asteroid population to date. Aims: We searched for spectroscopic analogues of the...

International audience

Astrophysical Journal, 694, Issue 2, pp. 1228-1236 (2009)

Here we present the first Gaia spectroscopic observations of asteroids. These data will be used to identify the composition of asteroids. Gaia will obtain the largest spectroscopic survey of the Main asteroid Belt.

Context. Understanding the conditions that lead to the formation of planetesimals – the building blocks of planets - and their initial size distribution is a central problem of modern planetology. While most of these original planetesimals were accreted onto the terrestrial planets and the cores of the giant planets, some were also stranded in...

Aims. This study aims to determine the size, albedo, and rotational period of (98943) 2001 CC21, a target of the Hayabusa2 extended mission, using thermal data from the Spitzer Space telescope and ground-based observations.Methods. The Spitzer data were acquired with the Infrared Spectrograph in the 6–38 μm range, reduced using the Spitzer...

Short period (<50 days) low-mass (<10Mearth) exoplanets are abundant and the few of them whose radius and mass have been measured already reveal a diversity in composition. Some of these exoplanets are found on eccentric orbits and are subjected to strong tides affecting their rotation and resulting in significant tidal heating. Within this...

Space missions1, 2 and thermal infrared observations3 have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by...

Space missions1, 2 and thermal infrared observations3 have shown that small asteroids (kilometre-sized or smaller) are covered by a layer of centimetre-sized or smaller particles, which constitute the regolith. Regolith generation has traditionally been attributed to the fall back of impact ejecta and by the break-up of boulders by...

We have developed a new three-parameter H, G1, G2 magnitude phase function for asteroids. The phase function is aimed at replacing the currently adopted two-parameter H, G phase function. We show that H, G1, G2 produces better fits of available magnitude - phase curves of well-observed asteroids. We show also that the new system can be...

The photometric signal we receive from a star hosting a planet is modulated by the variation of the planet signal with its orbital phase. Already observed for giant exoplanets, those thermal phase curves should be measured with future telescopes (JWST and EChO) for hot rocky Super-Earths in transiting and nontransiting configurations. The...

Context. Disk-integrated photometric data of asteroids do not contain accurate information on shape details or size scale. Additional data such as disk-resolved images or stellar occultation measurements further constrain asteroid shapes and allow size estimates. Aims: We aim to use all the available disk-resolved images of approximately forty...

There have been attempts in the past to fit the observed bulk shapes (axial ratios) of asteroids to theoretical equilibrium figures for fluids, but these attempts have not been successful in many cases, evidently because asteroids are not fluid bodies. So far, however, the observed distribution of asteroid macroscopic shapes has never been...

In this note, we show that neither the age of an object, nor its mineralogy is discriminant enough for revealing its primitiveness, and propose a new parameterization scheme based on the processes the matter underwent since its delivery to the Solar System. By ranking celestial objects and their constituents, two antagonistic sources of...

Context. Observational and instrumental difficulties observing small bodies below 0.5 μm make this wavelength range poorly studied compared with the visible and near-infrared. Furthermore, the suitability of many commonly used solar analogues, essential in the computation of asteroid reflectances, is usually assessed only in visible...