Papers by Mario Di Martino
Meteoritics & Planetary Science, 2021
The Cavezzo meteorite, which fell on January 1, 2020, is the first meteorite detected and recover... more The Cavezzo meteorite, which fell on January 1, 2020, is the first meteorite detected and recovered by the Italian PRISMA Fireball Network. Two specimens, weighing 3.12 g (specimen 1) and 52.19 g (specimen 2), were collected 3 days after the bolide was observed, thanks to an effective media campaign that encouraged the involvement of local people. The two specimens of this meteorite have not only completely different lithological characteristics but also a different geochemistry and oxygen isotopic composition as well. Specimen 1 is anomalous both for the textural–structural features, varying seamlessly from chondritic to “achondritic,” and a very unusual modal mineralogy—such as the relatively high amount of olivine (63.1 vol%), plagioclase (18.2 vol%), high‐Ca pyroxene (10.3 vol%), and chlorapatite (2.1 vol%); and the unusually low content of low‐Ca pyroxene (5.8 vol%), metal (0.1 vol%), and troilite (much lesser than 0.1 vol%)—although the compositional values for olivine (Fa 24....
Encyclopedic Atlas of Terrestrial Impact Craters, 2019
Near-Earth asteroid 1998 WT24 will have a very close approach to Earth at a distance of 0.012 AU ... more Near-Earth asteroid 1998 WT24 will have a very close approach to Earth at a distance of 0.012 AU on 16 December 2001. We are planning the radar observation of this asteroid at 6 cm wavelength using a bistatic system: Evpatoria, Crimea, 70-m dish and power transmitter → Medicina, near Bologna, Italy, 32-m dish and two-channel receiver. The essence of this proposal is to use the two antennas also to carry out the first attempt of centimetric space debris (SD) radar detection in geostationary ring, on October-November 2001, the scheduled period for the Evpatoria → Medicina system testing. 1. GEO SCAN EXPERIMENT Unlike the LEO space debris, the GEO region cannot be scanned to take advantage of the Earth’s rotation. Moreover, the GEO region represents a relatively narrow layer with more definite coordinates, where the dominant orbital period of GEO objects is near 24 hour, so in beam park case the event frequency will be very small. Therefore, in order to detect by radar any uncatalogued...
Asteroids III, 2002
The population of near-Earth objects (NEOs) contains asteroids, comets, and the precursor bodies ... more The population of near-Earth objects (NEOs) contains asteroids, comets, and the precursor bodies for meteorites. The challenge for our understanding of NEOs is to reveal the proportions and relationships between these categories of solar-system small bodies and their source(s) of resupply. Even accounting for strong bias factors in the discovery and characterization of higheralbedo objects, NEOs having S-type spectra are proportionally more abundant than within the main asteroid belt as a whole. Thus, an inner asteroid belt origin (where S-type objects dominate) is implied for most NEOs. The identification of a cometary contribution within the NEO population remains one of a case-by-case examination of unusual objects, and the sum of evidence suggests that comets contribute at most only a few percent of the total. With decreasing size and younger surfaces (due to presumably shorter collisional lifetimes for smaller objects), NEOs show a transition in spectral properties toward resembling the most common meteorites, the ordinary chondrites. Ordinary chondritelike objects are no longer rare among the NEOs, and at least qualitatively it is becoming understandable why these objects comprise a high proportion of meteorite falls. Comparisons that can be performed between asteroidal NEOs and their main-belt counterparts suggest that the physical properties (e.g., rotation states, configurations, spectral colors, surface scattering) of NEOs may be representative of main-belt asteroids (MBAs) at similar (but presently unobservable) sizes.
Transient phenomena on planetary bodies are defined as luminous events of different intensities, ... more Transient phenomena on planetary bodies are defined as luminous events of different intensities, which occur in planetary atmospheres and surfaces, their duration spans from about 0.1 s to some hours. They consist of meteors, bolides, lightning, impact flashes on solid surfaces, auroras, etc. So far, the study of these phenomena has been very limited, due to the lack of an ad hoc instrumentation, and their detection has been performed mainly on a serendipitous basis. Recently, ESA has issued an announcement of opportunity for the development of systems devoted to the detection of transient events in the Earth atmosphere and/or on the dark side of other planetary objects. One of such a detector as been designed and a prototype (Smart Panoramic Optical Sensor Head, SPOSH) has been constructed at Galileo Avionica S.p.A (Florence, Italy). For sake of clarity, in what follows, we classify the transient phenomena in "Earth phenomena" and "Planetary phenomena", even though some of them originate in a similar physical context.
Astronomy and Astrophysics
In the last few years it has been pointed out that, from both physical and dynamical point of vie... more In the last few years it has been pointed out that, from both physical and dynamical point of view, it is becoming more and more difficult to distinguish comets from asteroids and indeed there are some examples of small bodies first designated as comets which had, later, to be reclassified as asteroids and vice versa . In order to investigate the evolutionary path of comets and asteroids in terms of both dynamical and physical properties, we performed spectroscopic observations of three objects discovered between 1990 and 1995 -(6042) 1990 WW 2 , (6144) 1994 EQ 3 , and 1995 QY 2 -and analyzed their orbital evolution. Obtained spectra show the typical trend of low-albedo, "primitive" objects, similar to those of outer-belt asteroids and comet nuclei. The dynamical analysis shows that (6042) 1990 WW 2 is on a stable orbit with a typical asteroidal behavior; (6144) 1994 EQ 3 is on a Jupitercrossing chaotic orbit and in the past could have spent some time in a Jupiter's horsehoe orbit; 1995 QY 2 is a Mars crosser and librates about the 15/7 resonance with Jupiter and has a 40% chance to make a transition from asteroid to comet orbit over a timescale of about 3-5×10 5 yr.
Nowadays radars provide a powerful source of information, often complementary to that obtained by... more Nowadays radars provide a powerful source of information, often complementary to that obtained by other observational techniques, about physical and dynamical properties of asteroids and space debris. A number of large Italian antennas, as radiotelescopes and telecommunication facilities, could be used as elements of a radar network for the study of Near Earth Objects (NEOs) and space debris orbital environment.
Proceedings of the International Astronomical Union, 2006
Near-Earth objects (NEOs) are objects of a special interest from the point of view not only of co... more Near-Earth objects (NEOs) are objects of a special interest from the point of view not only of cosmogonic problems of the Solar system, but of the applied problems as well (the problem of asteroid hazard, NEOs as the potential sources of raw materials, etc.). They are much smaller in sizes than main-belt asteroids (MBAs), very irregular in shape and covered with a great number of craters of different sizes. Most of NEOs are covered by regolith of low thermal inertia and different thickness. Objects with complex non-principal axis rotation (tumbling bodies) and with super-fast rotational periods have been detected among them. The new data, based on photometric and radar observations, evidence that about 15-20 %; of NEOs could be binary systems. Most of the classified NEOs fragments of differentiated assemblages of S-and Q-types. Analysis of physical properties of NEOs clearly indicates that the asteroid main-belt is the principal source of their origin and only about 10 % of NEOs hav...
ABSTRACT Impact craters up to a few hundreds of meters in diameter are common structures of solid... more ABSTRACT Impact craters up to a few hundreds of meters in diameter are common structures of solid surfaces of planetary bodies in the solar system. Statistics predict that impacts producing small craters on Earth occur on decadal to secular time scales (1, 2). However, small craters are rare on Earth because they are rapidly eroded, and the few identified so far [15 <300 m in diameter out of 176 craters up to 300 km in diameter (3)] have lost most of their primary features. We report the detection in southern Egypt of a rayed impact crater 45min diameter (Fig. 1A) on a Cretaceous sandstone target. The ejecta rays highlight the exceptional freshness of the structure. The crater was identified by V. De Michele during a Google Earth survey and named Kamil Crater after nearby Gebel Kamil. A geophysical expedition undertaken [supporting online material (SOM)] in February 2010 revealed that the crater is bowl shaped and has an upraised rim (~3 m above preimpact surface) (figs. S1 and S2) typical of simple craters (4). The true crater floor depth is 16 m and is overlain by ~6-m-thick crater-fill material (fig. S2). Morphometric parameters agree with those predicted by models (5) for a transient crater generated by an iron meteorite 1.3 min diameter (equivalent to 9.1 × 103 kg) impacting at a velocity of 3.5 kms−1, assuming an average meteoroid entry velocity and entry angle of 18 kms−1 and 45°, respectively. Centimeterscale masses of scoriaceous impact melt glass (fig. S3) occur in and close to the crater and indicate local shock pressures >60 GPa (4). We identified 5178 iron meteorite specimens totaling ~1.71 tons in the crater and surrounding area during systematic searches (SOM). They consist of <34-kg shrapnel produced by the explosion of the impactor upon hypervelocity collision with the target (Fig. 1B), except one individual fragment of 83 kg (fig. S4). This evidence indicates that the Kamil Crater was generated by an impactor that landed nearly intact without substantial fragmentation in the atmosphere. The meteorite is classified as an ungrouped Ni-rich ataxite [Ni = 19.8 weight % (wt %), Co = 0.75 wt %, Ga = 49.5 mg g−1, Ge = 121 mg g−1, Ir = 0.39 mg g−1; data following (6); fig. S5]. Magnetic anomaly data show no evidence of buried meteorites larger than some tens of centimeters (fig. S1). On the basis of systematic meteorite searches, the estimated total mass of the impactor is of the order of 5 ×103 to 10 × 103 kg, corresponding to a preatmospheric mass of ~20 ×103 to 40 × 103 kg (2). According to geophysical models (2, 7), iron masses <3 × 106 kg normally fragment upon impact with Earth’s atmosphere, thereby reducing the energy of the impact at Earth’s surface. However, the present statistics, which include the recently discovered Whitecourt Crater (8) and the Kamil Crater, suggest that ~35% of the iron meteorites in the above mass range are not disrupted in the atmosphere.
Astronomy & Astrophysics - ASTRON ASTROPHYS, 1997
Rotationally resolved visible spectroscopy (6000~9500Å) of (7) Iris is presented. Within a few pe... more Rotationally resolved visible spectroscopy (6000~9500Å) of (7) Iris is presented. Within a few percents, no variation in Iris' visible spectrum over a rotational period has been found. These data suggest that the mineralogic properties of Iris' surface are globally homogeneous, although we cannot exclude the presence of some texture and/or albedo variegation as suggested by previous photometric and polarimetric studies available in the literature. From a dynamical point of view, we estimate the ejection velocity required for collisional fragments from this asteroid to be injected into the surrounding chaotic regions. The resulting velocity values are fairly high, but not incompatible with the values suggested by the present knowledge of catastrophic break-up phenomena and by the observational constraints put by asteroid families. Taking into account the close similarity between Iris' spectrum and that of (6) Hebe, a typical S(IV)-type object according with the most mo...
Astronomy and …, 1997
Some years ago we started a spectroscopic survey, in the visible region, of Earth-approaching ast... more Some years ago we started a spectroscopic survey, in the visible region, of Earth-approaching asteroids to investigate their compositional nature in order to improve the comprehension of their origin. To date we have obtained low-resolution spectra, in the range 0.
The Astronomical Journal, 2011
We present the results of a Jupiter Trojans' light curve survey aimed at characterizing the rotat... more We present the results of a Jupiter Trojans' light curve survey aimed at characterizing the rotational properties of Trojans in the approximate size range 60-150 km. The survey, which was designed to provide reliable and unbiased estimates of rotation periods and amplitudes, resulted in light curves for a total of 80 objects, 56 of which represent the first determinations published to date and nine of which supersede previously published erroneous values. Our results more than double the size of the existing database of rotational properties of Jovian Trojans in the selected size range. The analysis of the distributions of the rotation periods and light curve amplitudes is the subject of companion papers.
Science, 2010
An unusually well-preserved 45-meter-diameter crater provides ground truth for small-scale meteor... more An unusually well-preserved 45-meter-diameter crater provides ground truth for small-scale meteorite impacts on Earth.
Icarus, 2001
Interferometric observations of asteroid (216) Kleopatra were performed in January 2000 using the... more Interferometric observations of asteroid (216) Kleopatra were performed in January 2000 using the Fine Guidance Sensors (FGS) aboard HST. The FGS data obtained clearly suggest that (216) Kleopatra is composed of two lobes in contact, in agreement with the radar data (Ostro et al. 2000, Science 288, 836-839), and provide more precise constraints on the absolute size of this peculiar object.
Icarus, 2008
We present the results of a visible spectroscopic and photometric survey of igneous asteroids bel... more We present the results of a visible spectroscopic and photometric survey of igneous asteroids belonging to the small and intriguing Eclass, including 2867 Steins, a target of the Rosetta mission. The survey was carried out at the 3.5m Telescopio Nazionale Galileo (TNG), and at the 3.5m New Technology Telescope (NTT) of the European Southern Observatory. We obtained new visible spectra for eighteen E-type asteroids, and near infrared spectra for eight of them. We confirm the presence of three different mineralogies in the small E-type populations. We classify each object in the E[I], E[II] or E[III] subgroups on the basis of the spectral behavior and of the eventual presence of absorption features attributed to sulfides (such the 0.49 µm band, on E[II]), or to iron bearing silicates (0.9 µm band, on E[III]). We suggest that some asteroids (i.e. 64 Angelina, 317 Roxane, and 434 Hungaria), which show different spectral behavior comparing our data with those available in literature, have an inhomogeneous surface composition. 2867 Steins, a target of the Rosetta mission, shows a spectral behavior typical of the E[II] subgroup, as already suggested by and Fornasier et al. (2007). Litva and 1990 TN1, initially classified as E-types, show a visible and near infrared behavior consistent with the olivine rich A-class asteroids, while 5806 Archieroy, also supposed to belong to the E-class, has a spectral behavior consistent with the S(V) classification following the Gaffey et al. (1993) classification scheme. To fully investigate the E-type population, we enlarged our sample including 6 E-type asteroids spectra available in literature, resulting in a total sample of 21 objects. The analysis of the spectral slope for the 3 different E-type subgroups versus the orbital elements show that E[III] members have the lowest mean spectral slope value inside the whole sample, and that they are located between 2.2-2.7 AU in low inclination orbits. E[II] members has the highest spectral slope inside the sample, half of them are located in the Hungaria region, 2 are NEA and 2 (64 Angelina and 2867 Steins), are in the main belt. A similar distribution is found for the 5 featureless E[I] members, located mainly in the Hungaria region (3 members), one in the middle main belt while one is a NEA (2004 VD17). Finally, for the five E-type asteroids observed both in the visible and near infrared range, plus 2867 Steins, we attempt to model their surface composition using linear geographycal mixtures of no more than 3 components, selected from aubrite meteorites and correlated minerals. In particular we suggest that the aubrite Peña Blanca might have the E[III] asteroid 317 Roxane as parent body, and that the aubrite ALH78113 might be related to the E[II] subgroup asteroids.
Geology, 2011
Email alerting services articles cite this article to receive free e-mail alerts when new www.gsa... more Email alerting services articles cite this article to receive free e-mail alerts when new www.gsapubs.org/cgi/alerts click to subscribe to Geology www.gsapubs.org/subscriptions/ click to contact GSA click official positions of the Society. citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect presentation of diverse opinions and positions by scientists worldwide, regardless of their race, includes a reference to the article's full citation. GSA provides this and other forums for the the abstracts only of their articles on their own or their organization's Web site providing the posting to further education and science. This file may not be posted to any Web site, but authors may post works and to make unlimited copies of items in GSA's journals for noncommercial use in classrooms requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in subsequent their employment. Individual scientists are hereby granted permission, without fees or further Copyright not claimed on content prepared wholly by U.S. government employees within scope of Notes articles must include the digital object identifier (DOIs) and date of initial publication.
ESA …, 2003
The terrestrial cratering record is unique in providing a detailed picture of the history of our ... more The terrestrial cratering record is unique in providing a detailed picture of the history of our Solar System over the last few billion years, as well as its celestial environment. The search for the scars of ancient cosmic impacts is therefore of fundamental importance from ...
Uploads
Papers by Mario Di Martino