Mauro Ciarniello

National Institute of Astrophysics | INAF · Institute for Space Astrophysics and Planetology IAPS

Aims . We present the most extensive catalog of exposures of volatiles on the 67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) on board the Rosetta mission. We investigate the volatile exposure distribution across the nucleus, their size distribution,...

We present the most extensive catalog of exposures of volatiles on the 67P/Churyumov-Gerasimenko nucleus generated from observations acquired with the OSIRIS cameras on board the Rosetta mission. We identified more than 600 volatile exposures on the comet. Bright spots are found isolated on the nucleus or grouped in clusters, usually at the bottom...

In this work, we present the most updated catalog of Io hot spots based on Juno/JIRAM data. We find 242 hot spots, including 23 previously undetected. Over the half of the new hot spots identified, are located at high northern and southern latitudes (>70°). We observe a latitudinal variability and a larger concentration of hot spots in the polar re...

We related morphological (size/shape) and dynamical properties of the dust ejected from the 67P/Churyumov-Gerasimenko comet by combining data from two instruments onboard the ESA's Rosetta mission, i.e., the MIDAS atomic force microscope and the GIADA dust detector. The two instruments detected dust of different size (10−6-10−5 and 10−4-10−3 m, res...

Albedo, spectral slopes, and water ice band depths maps for the five midsized saturnian satellites Mimas, Enceladus, Tethys, Dione, and Rhea have been derived from Cassini-Visual and Infrared Mapping Spectrometer (VIMS) data. The maps are systematically built from photometric corrected data by applying the Kaasalainen-Shkuratov model (Kaasalainen e...

The last thirty years of cosmochemistry and planetary science have shown that one major Solar System reservoir is vastly undersampled in the available suite of extra-terrestrial materials, namely small bodies that formed in the outer Solar System (>10 AU). Because various dynamical evolutionary processes have modified their initial orbits (e.g., gi...

We analyzed the surface of Vesta at visible wavelengths, using the data of the Visible and InfraRed mapping spectrometer (VIR) on board the Dawn spacecraft. We mapped the variations of various spectral parameters on the entire surface of the asteroid, and also derived a map of the lithology. We took advantage of the recent corrected VIR visible dat...

Aims. We analyzed the surface of Vesta at visible wavelengths, using the data of the Visible and InfraRed mapping spectrometer (VIR) on board the Dawn spacecraft. We mapped the variations of various spectral parameters on the entire surface of the asteroid, and also derived a map of the lithology. Methods. We took advantage of the recent corrected...

The Howardites-Eucrite-Diogenite achondrite family is recognized to be the set of extraterrestrial rocks coming from (4) Vesta and Vestoids. In fact, the similar values of oxygen isotopes, and some chemical variation permit to associate these rocks to a system genetically correlated. Reflectance spectral properties permit an association between the...

Thermal inertia is a key information to quantify the physical status of a planetary surface; it can be retrieved by comparison between theoretical and observed temperature diurnal profiles. We have calculated the surface temperature for a set of locations on Ceres' surface with a thermophysical model that provides temperature as a function of therm...

Ammonium phyllosilicates have been identified on the dwarf planet Ceres, thanks to infrared telescopic and orbital data from the Dawn mission, by means of the 3.06 μm spectral feature. Nevertheless, it is not known which ammonium‐bearing phyllosilicate species are present, nor the thermal processing they underwent throughout Ceres history. Identify...

The Jovian InfraRed Auroral Mapper (JIRAM) on board the NASA Juno spacecraft is a dual‐band imager and spectrometer in the 2–5 μm range with 9‐nm spectral sampling, primarily designed to study the Jovian atmosphere and aurorae. In addition to these goals, JIRAM is used to obtain images and spectra of the Galilean satellites, every time the spacecra...

The Visible‐Infrared Mapping Spectrometer (VIR) on board the Dawn spacecraft revealed that aqueous secondary minerals—Mg‐phyllosilicates, NH4‐bearing phases, and Mg/Ca carbonates—are ubiquitous on Ceres. Ceres' low reflectance requires dark phases, which were assumed to be amorphous carbon and/or magnetite (∼80 wt.%). In contrast, the Gamma Ray and...

This work describes the correction method applied to the dataset acquired at the asteroid (4) Vesta by the visible channel of the visible and infrared mapping spectrometer. The rising detector temperature during data acquisitions in the visible wavelengths leads to a spectral slope increase over the whole spectral range. This limits the accuracy of...

The Visible‐Infrared Mapping Spectrometer (VIR) on board the Dawn spacecraft revealed that aqueous secondary minerals—Mg‐phyllosilicates, NH4‐bearing phases, and Mg/Ca carbonates—are ubiquitous on Ceres. Ceres' low reflectance requires dark phases, which were assumed to be amorphous carbon and/or magnetite (∼80 wt.%). In contrast, the Gamma Ray and...

This work describes the correction method applied to the dataset acquired at the asteroid (4) Vesta by the visible channel of the visible and infrared mapping spectrometer. The rising detector temperature during data acquisitions in the visible wavelengths leads to a spectral slope increase over the whole spectral range. This limits the accuracy of...

The surface composition of Io is dominated by SO2 frost, plus other chemical species identified or proposed over the past decades by combining Earth‐based and space‐based observations with laboratory data. Here we discuss spectroscopic data sets of Io obtained by the Jovian InfraRed Auroral Mapper (JIRAM) spectro‐imager onboard Juno in nine orbits,...

The Visible-Infrared Mapping Spectrometer (VIR) on board the Dawn spacecraft revealed that aqueous secondary minerals -- Mg-phyllosilicates, NH4-bearing phases, and Mg/Ca carbonates -- are ubiquitous on Ceres. Ceres' low reflectance requires dark phases, which were assumed to be amorphous carbon and/or magnetite (~80 wt.%). In contrast, the Gamma R...

Aims. We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We also focus on several noteworthy areas of the surface of this dwarf planet. Methods. We made use of the new...

We study the surface of Ceres at visible wavelengths, as observed by the Visible and InfraRed mapping spectrometer (VIR) onboard the Dawn spacecraft, and analyze the variations of various spectral parameters across the whole surface. We also focus on several noteworthy areas of the surface of this dwarf planet. We made use of the newly corrected VI...

The ESA Rosetta mission has acquired unprecedented measurements of comet 67/P-Churyumov-Gerasimenko (hereafter 67P) nucleus surface, whose composition, as determined by in situ and remote sensing instruments including VIRTIS (Visible, InfraRed and Thermal Imaging Spectrometer) appears to be made by an assemblage of ices, minerals, and organic mater...

Photometric correction based on the Shkuratov method is applied to derive visible and infrared albedo maps of Rhea from disc-resolved Cassini VIMS data. Differently from I/F images, albedo maps offer an optimal disentanglement of composition and physical properties of the surface from illumination-viewing effects and to study spectral variations oc...

We aim at retrieving physical and compositional surface properties of the nucleus of comet 67P/Churyumov-Gerasimenko (hereafter 67P) from VIS-IR hyperspectral images (‘cubes’). Here we report on our progress in the geometric modeling and spectral fitting.

The surface and internal structure of Ceres show evidence of a global process of aqueous alteration, indicating the existence of an ocean in the past. However, it is not clear whether part of this ocean is still present and whether residual fluids are still circulating in the dwarf planet. These fluids may be exposed in a geologically young surface...

We characterized the 67P/Churyumov–Gerasimenko’s dust activity, by analysing individual dust particle velocity and momentum measurements of Grain Impact Analyser and Dust Accumulator (GIADA), the dust detector onboard the ESA/Rosetta spacecraft, collecting dust from tens to hundreds of kilometres from the nucleus. Specifically, we developed a proce...

The VIRTIS imaging spectrometer on board Rosetta has shown that the nucleus surface of comet 67P/Churyumov-Gerasimenko (67P/CG) is characterized by a broad absorption band at around 3.2 μm. The feature is ubiquitous across the surface and its attribution to (a) specific material(s) has been challenging. In the present Letter, we report an experimen...

We characterized the 67P/Churyumov-Gerasimenko"s dust activity, by analyzing individual dust particle velocity and momentum measurements of GIADA (Grain Impact Analyser and Dust Accumulator), the dust detector on board the ESA/Rosetta spacecraft, collecting dust from tens to hundreds of kilometers from the nucleus. Specifically, we developed a proc...

The European Space Agency’s Rosetta mission1 has acquired unprecedented measurements of the surface of the nucleus of comet 67P/Churyumov–Gerasimenko (hereafter, 67P), the composition of which, as determined by in situ and remote-sensing instruments, including the VIRTIS instrument2, seems to be an assemblage of ices, minerals and organic material3...

Ammonium salts on comet 67P The distribution of carbon and nitrogen in the Solar System is thought to reflect the stability of carbon- and nitrogen-bearing molecules when exposed to the heat of the forming Sun. Comets have a low nitrogen-to-carbon ratio, which is contrary to expectations because they originate in the outer Solar System where nitrog...

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the b...

Thermal inertia is a key information to quantify the physical status of a planetary surface. We derive the thermal inertia of the surface of Ceres using spatially resolved data from the Dawn mission. For each location, this quantity can be constrained by comparing theoretical and observed diurnal temperature profiles from retrieved temperatures. We...

Solar heating of a cometary surface provides the energy necessary to sustain gaseous activity, through which dust is removed1,2. In this dynamical environment, both the coma3,4 and the nucleus5,6 evolve during the orbit, changing their physical and compositional properties. The environment around an active nucleus is populated by dust grains with c...

Context. Particulate surfaces exhibit a surge of reflectance at low phase angles, a phenomenon referred to as the opposition effect (OE). Two mechanisms are recognized as responsible for the OE: shadow hiding (SH) and coherent backscattering. The latter is typically characterized by a small angular width of a few degrees at most and according to th...

Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are respectively a CCD and a HgCdTe array. The variations of the visible channel temperatures measured during the sessi...

Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are, respectively, a charged coupled device and a HgCdTe array. The variations of the visible channel temperatures meas...

On 2015 July 18, near perihelion at a heliocentric distance of 1.28 au, the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-M) on board the Rosetta spacecraft had the opportunity of observing dust activity in the inner coma with a view of the night side (shadowed side) of comet 67P/Churyumov-Gerasimenko. At the time of the measurements we pre...

Context. On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet. Aims: We aim to characterize the spatial distribution of dust, H...

On 2015 July 18, near perihelion at a heliocentric distance of 1.28 au, the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-M) on board the Rosetta spacecraft had the opportunity of observing dust activity in the inner coma with a view of the night side (shadowed side) of comet 67P/Churyumov-Gerasimenko. At the time of the measurements we pre...

Following earlier surface spectrophotometric analyses of Rosetta/VIRTIS-M measurements of comet 67P/Churyumov-Gerasimenko (hereafter 67P), we refine the instrument's geometric registration model and spatial consistency of the radiometric calibration. For this purpose we compare measured 67P nucleus images from the entire mission to corresponding ph...

Knowledge of the surface temperature distribution on a comet’s nucleus and its temporal evolution at different timescales is key to constraining its thermophysical properties and understanding the physical processes that take place at and below the surface. Here we report on time-resolved maps of comet 67P/Churyumov–Gerasimenko retrieved on the bas...

On 27 Apr 2015, when 67P/C-G was at 1.76 au from the Sun and moving towards perihelion, the OSIRIS and VIRTIS-M instruments on Rosetta observed the evolving dust and gas coma during a complete rotation of the comet. We aim to characterize the dust, H2O and CO2 gas spatial distribution in the inner coma. To do this we performed a quantitative analys...

We report a comprehensive analysis of the global spectrophotometric properties of Ceres using the images collected by the Dawn Framing Camera through seven color filters from April to June 2015 during the RC3 (rotational characterization 3) and Survey mission phases. We derived the Hapke model parameters for all color filters. The single-scattering...

Cassini's last look at Saturn's rings During the final stages of the Cassini mission, the spacecraft flew between the planet and its rings, providing a new view on this spectacular system (see the Perspective by Ida). Setting the scene, Spilker reviews the numerous discoveries made using Cassini during the 13 years it spent orbiting Saturn. Iess et...

We performed spectral analyses on four serendipitous observations of Europa acquired by the JIRAM instrument (Adriani et al., 2017) onboard the Juno mission. Due to the fixed orientation of the spacecraft spin axis and orbital plane placed along terminator, Europa is observed at approximately 90° phase angle from distances >3.35E5 km resulting in a...

We characterized 67P/Churyumov–Gerasimenko's cometary activity during its inbound arc before perihelion (2014 August–2015 January). We focused on the geomorphological regions of the Northern hemisphere observed by the ESA/Rosetta space probe during this time period. The GIADA dust detector characterized the physical properties of the fluffy and com...

We review our current knowledge of comet 67P/Churyumov–Gerasimenko nucleus composition as inferred from measurements made by remote sensing and in-situ instruments aboard Rosetta orbiter and Philae lander. Spectrophotometric properties (albedos, color indexes and Hapke parameters) of 67P/CG derived by Rosetta are discussed in the context of other c...

The surface mineralogy of dwarf planet Ceres appears to be dominated by products of rock–fluid interactions, such as phyllosilicates—some of which are NH4-bearing—and carbonates1–3. Elemental concentrations derived from the inferred mineral mixing fractions, however, do not match measurements of H, C, K and Fe on Ceres4. A complicating factor in as...

We analyze 2–5 μ m spectroscopic observations of the dust coma of comet 67P/Churyumov-Gerasimenko obtained with the Visible InfraRed Thermal Imaging Spectrometer (VIRTIS-H) instrument on board Rosetta from 3 June to 29 October 2015 at heliocentric distances rh = 1.24–1.55 AU. The 2–2.5 μ m color, bolometric albedo, and color temperature were measur...

Ceres is the largest object in the main belt and is a wet body with a complex geological and chemical history. Its surface is composed of opaque materials, phyllosilicates, ammoniated-bearing minerals, carbonates, water ice, and salts. Recently, aliphatic organics, whose origin is still uncertain, have also been detected on the Ceres surface by the...

We analyze 2-5 micrometre spectroscopic observations of the dust coma of comet 67P/Churyumov-Gerasimenko obtained with the VIRTIS-H instrument onboard Rosetta from 3 June to 29 October 2015 at heliocentric distances r_h = 1.24-1.55 AU. The 2-2.5 micrometre color, bolometric albedo, and color temperature are measured using spectral fitting. Data obt...

We studied the distribution in the Urvara–Yalode region of Ceres (latitudes 21–66°S, longitudes 180–360°E) of main spectral parameters derived from the VIR imaging spectrometer onboard the NASA/Dawn spacecraft, as an overall study of Ceres mineralogy reported in this special issue. In particular, we analyzed the distribution of reflectance at 1.2 µ...

We report a comprehensive analysis of the global spectrophotometric properties of Ceres using Dawn Framing Camera images collected from April to June 2015 during the RC3 and Survey mission phases. The single-scattering albedo of Ceres at 555 nm is 0.14$\pm$0.04, the geometric albedo is 0.096$\pm$0.006, and the Bond albedo is 0.037$\pm$0.002. The as...

We present an analysis of transient events observed by the Visible InfraRed Thermal Imaging Spectrometer, instrument aboard Rosetta, for the dates of 2015 August 10, September 13 and 14, during the two months surrounding the comet perihelion passage of the Rosetta spacecraft. We detected and characterized events with life-times ranging from 26 min...

Context. The surface reflectance of planetary regoliths may increase dramatically towards zero