P. H. Hasselmann
A5078802013- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- Geological and Geochemical Analysis
- Geology and Paleoclimatology Research
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Space Satellite Systems and Control
- Astronomical and nuclear sciences
- High-pressure geophysics and materials
- Space Exploration and Technology
- Radioactive Decay and Measurement Techniques
- Spaceflight effects on biology
- Astronomical Observations and Instrumentation
- Marine and environmental studies
- Radioactive contamination and transfer
- Spacecraft and Cryogenic Technologies
- Astrophysics and Star Formation Studies
- Fluid Dynamics Simulations and Interactions
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Scientific Research and Discoveries
Astronomical Observatory of Rome
2022-2025
National Institute for Astrophysics
2022-2025
Université Paris Sciences et Lettres
2015-2024
Université de Versailles Saint-Quentin-en-Yvelines
2015-2024
Sorbonne Université
2015-2024
Université Paris Cité
2015-2024
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2014-2024
Observatoire de Paris
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Osservatorio Astronomico di Padova
2022
Abstract The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of binary (65803) Didymos, at 23:14 UTC 26 September 2022 as planetary defence test 1 . DART was first hypervelocity experiment an size and velocity scales relevant to defence, intended validate means deflection. Here we report determination momentum transferred by impact. On basis change in orbit period 2 , find instantaneous reduction Dimorphos’s along-track...
Some active asteroids have been proposed to be formed as a result of impact events1. Because are generally discovered by chance only after their tails fully formed, the process how ejecta evolve into tail has, our knowledge, not directly observed. The Double Asteroid Redirection Test (DART) mission NASA2, in addition having successfully changed orbital period Dimorphos3, demonstrated activation an asteroid resulting from under precisely known conditions. Here we report observations DART with...
Abstract NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, and mission's Level 1 requirements guided its planetary defense investigations. Here, we summarize DART's achievement of those requirements. On 2022 September 26, DART spacecraft impacted Dimorphos, secondary member Didymos near-Earth binary system, demonstrating an autonomously navigated kinetic impact into with limited prior knowledge for defense. Months subsequent Earth-based...
Abstract The Double Asteroid Redirection Test (DART) had an impact with Dimorphos (a satellite of the asteroid Didymos) on 26 September 2022 1 . Ground-based observations showed that Didymos system brightened by a factor 8.3 after because ejecta, returning to pre-impact brightness 23.7 days afterwards 2 Hubble Space Telescope made from 15 minutes 18.5 after, spatial resolution 2.1 kilometres per pixel, complex evolution ejecta 3 , consistent other events. momentum enhancement factor,...
On September 26, 2022, NASA's Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of binary near-Earth asteroid (65803) Didymos. Numerical simulations impact provide a means to explore target surface material properties and structures, consistent with observed momentum deflection efficiency, ejecta cone geometry, ejected mass. Our simulation, which best matches observations, indicates that Dimorphos is weak, cohesive strength less than few...
Abstract Images collected during NASA’s Double Asteroid Redirection Test (DART) mission provide the first resolved views of Didymos binary asteroid system. These images reveal that primary asteroid, Didymos, is flattened and has plausible undulations along its equatorial perimeter. At high elevations, surface rough contains large boulders craters; at low elevations smooth possesses fewer craters. Didymos’ moon, Dimorphos, an intimate mixture boulders, several asteroid-wide lineaments, a...
Context. The Rosetta mission of the European Space Agency has been orbiting comet 67P/Churyumov-Gerasimenko (67P) since August 2014 and is now in its escort phase. A large complement scientific experiments designed to complete most detailed study a ever attempted are onboard Rosetta.
<i>Aims. <i/> The present paper aims to derive a new classification scheme for SDSS MOC asteroid colors that is compatible with previous taxonomies based on spectroscopic data. distribution of these can give important clues the formation and evolution this region Solar System, as well locate candidates mineralogically interesting spectra detailed observations. <i>Methods. <i/>The methodology large database MOC4. Templates main taxonomic classes are derived then used classify observations in...
Visible-wavelength color and reflectance provide information about the geologic history of planetary surfaces. Here we present multispectral images (0.44 to 0.89 micrometers) near-Earth asteroid (101955) Bennu. The surface has variable colors overlain on a moderately blue global terrain. Two primary boulder types are distinguishable by their texture. Space weathering Bennu materials does not simply progress from red (or vice versa). Instead, freshly exposed, redder surfaces initially...
Abstract Asteroids smaller than 10 km are thought to be rubble piles formed from the reaccumulation of fragments produced in catastrophic disruption parent bodies. Ground-based observations reveal that some these asteroids today binary systems, which a secondary orbits larger primary asteroid. However, how became systems remains unclear. Here, we report analysis boulders on surface stony asteroid (65803) Didymos and its moonlet, Dimorphos, data collected by NASA DART mission. The...
Abstract Spacecraft observations revealed that rocks on carbonaceous asteroids, which constitute the most numerous class by composition, can develop millimeter-to-meter-scale fractures due to thermal stresses. However, signatures of this process second-most populous group S-complex, have been poorly constrained. Here, we report boulders’ Dimorphos, is moonlet S-complex asteroid (65803) Didymos, target NASA’s Double Asteroid Redirection Test (DART) planetary defense mission. We show...
Since the orbital insertion of Rosetta spacecraft, comet 67P/Churyumov-Gerasimenko (67P/C-G) has been mapped by OSIRIS camera and VIRTIS spectro-imager, producing a huge quantity images spectra comet's nucleus. The aim this work is to search for presence H$_2$O on nucleus which, in general, appears very dark rich dehydrated organic material. After selecting bright spots which could be good candidates ice, taken at high resolution OSIRIS, we check spectral cubes selected coordinates identify...
The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute cometary-specific weathering, erosion, transient events driven by exposure sunlight other processes. While the suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations comet's...
On 3 July 2016, several instruments on board ESA's Rosetta spacecraft detected signs of an outburst event comet 67P, at a heliocentric distance 3.32 AU from the sun, outbound perihelion. We here report inferred properties ejected dust and surface change site outburst. The activity coincided with local sunrise continued over time interval 14 - 68 minutes. It left 10m-sized icy patch surface. material comprised refractory grains hundred microns in size, sub-micron-sized water ice grains. high...
The study of dust, the most abundant material in cometary nuclei, is pivotal understanding original materials forming Solar system. Measuring coma phase function provides a tool to investigate nature dust. Rosetta/OSIRIS sampled comet 67P/Churyumov–Gerasimenko, covering large angle range small amount time. Twelve series were acquired period from 2015 March 2016 February for this scientific purpose. These data allowed, after stray light removal, measuring shape, its reddening, and reddening...
Abstract We modeled the geometry and three-dimensional orientation of ejecta cone triggered by impact DART spacecraft on asteroid Dimorphos. used eight LUKE images acquired CubeSat LICIACube that flew Didymos system shortly after impact. These images, which show in both face-on side-on profiles, enabled us to reconstruct inertial space. started our model as a simple with circular base developed it rotated an elliptical best fit data. The axis points R.A., decl. (in J2000): <?CDATA...
Abstract The NASA Double Asteroid Redirection Test (DART) spacecraft impacted the moon Dimorphos of [65803] Didymos binary system and changed orbit period, demonstrating asteroid deflection by a kinetic impact indicating that more momentum was transferred to escaping ejecta than incident with DART. Images DART plume were obtained Light Italian cubesat for Imaging Asteroids (LICIACube) in first few minutes after impact. imaged LICIACube 158 s prior closest approach shows no evidence clearing...
OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) is a NASA mission to return sample of asteroid (101955) Bennu. Photometric modeling Bennu's surface key element both site characterization our broader scientific understanding the asteroid. heterogeneous presents substantial variation in reflectance produces scattered dataset that poses challenge photometric modeling. We show resolution shape model with which we calculate angles strongly...
Abstract The smallest member of the Didymos binary near-Earth object system (Dimorphos) is target DART/LICIACube mission, first attempt to change orbit another celestial body via a kinetic impactor. It important characterize unperturbed prior DART impact. In this work we obtained, for time, spectral characterization at several rotational phases from TNG+DOLORES in visible range (0.34–0.81 μ m). This crucial order disentangle primary and secondary bodies highlight eventual dishomogeneities on...
The NASA mission OSIRIS-REx has been observing near-Earth asteroid (101955) Bennu in close proximity since December 2018. In this work, we investigate spectral phase reddening -- that is, the variation of slope with angle on using spectra acquired by Visible and InfraRed Spectrometer (OVIRS) covering a range 8-130$^{o}$. We process at global scale for some localized regions interest (ROIs), including boulders, craters, designated sample collection sites mission. globally negative slope,...