First disk-resolved spectroscopy of (4) Vesta

Vesta, the second largest Main Belt asteroid, will be the first to be explored in 2011 by NASA's Dawn mission. It is a dry, likely differentiated body with spectrum suggesting that is has been resurfaced by basaltic lava flows, not too different from the lunar maria. Here we present the first disk-resolved spectroscopic observations of an asteroid from the ground. We observed (4) Vesta with the ESO-VLT adaptive optics equipped integral-field near-infrared spectrograph SINFONI, as part of its science verification campaign. The highest spatial resolution of ~90 km on Vesta's surface was obtained during excellent seeing conditions (0.5") in October 2004. We observe spectral variations across Vesta's surface that can be interpreted as variations of either the pyroxene composition, or the effect of surface aging. We compare Vesta's 2 micron absorption band to that of howardite-eucrite-diogenite (HED) meteorites that are thought to originate from Vesta, and establish particular links between specific regions and HED subclasses. The overallcomposition is found to be mostly compatible with howardite meteorites, although a small area around 180 deg. East longitude could be attributed to a diogenite-rich spot. We finally focus our spectral analysis on the characteristics of Vesta's bright and dark regions as seen from Hubble Space Telescope's visible and Keck-II's near-infrared images.Comment: 13 pages, 11 figures, 3 table

Taxonomy of Centaurs and Trans-Neptunian Objects

The original publication is available at http://iopscience.iop.org/1538-3881/.International audienceTrans-Neptunian objects (TNOs) and Centaurs display thewidest color diversity in comparison to other small solar system bodies. The investigation of their properties can help in understanding the evolution of these objects. In this paper we propose a classification scheme based on multivariate statistical analysis of a homogeneous, high-quality set of B - V, V - R, V - I , and V - J color indices. Analyzing a sample of 51 objects and using a high confidence level, four groups have been identified and named: BB, BR, IR, and RR. The group BB contains objects with neutral color and RR those with very red color, while the others have intermediate behavior. We extend the analysis to 84 other objects for which three colors are available, obtaining a preliminary classification. A tentative interpretation of these groups in terms of surface characteristics is given

Philosophy and updating of the asteroid photometric catalogue

The Asteroid Photometric Catalogue now contains photometric lightcurves for 584 asteroids. We discuss some of the guiding principles behind it. This concerns both observers who offer input to it and users of the product

Rosetta Asteroid Candidates

AbstractThe new scenario of the Rosetta mission to comet 67/P Churyumov-Gerasimenko (launch on February 2004), includes as baseline the fly-by of one or two asteroids. Several asteroids are now possible fly-by candidates (single or double) within the available resources. Other candidates whose fly-bys require a larger Δv can be also considered if the Rosetta interplanetary orbit insertion will cost less Δv.All the up to date available information on the possible targets are discussed in this report

E-type asteroid (2867) Steins: flyby target for Rosetta

Reproduced with permission. Copyright ESO. Article published by EDP Sciences and available at http://www.aanda.org.International audienceAims. The mineralogy of the asteroid (2867) Steins was investigated in the framework of a ground-based science campaign dedicated to the future encounter with Rosetta spacecraft. Methods. Near-infrared (NIR) spectra of the asteroid in the 0.8−2.5 μm spectral range have been obtained with SpeX/IRTF in remoteobserving mode from Meudon, France, and Cambridge, MA, in December 2006 and in January and March 2007. A spectrum with a combined wavelength coverage from 0.4 to 2.5 μm was constructed using previously obtained visible data. To constrain the possible composition of the surface, we constructed a simple mixing model using a linear (areal) mix of three components obtained from the RELAB database. A space-weathering model was applied to the aubrite ALH-78113 spectrum. Results. The four new NIR spectra reveal no major absorption features. The best-fit model for the constructed visible-plus-NIR spectrum is represented by a mixture of 57% enstatite, 42% oldhamite, and 1% orthopyroxene. These results place Steins in a subdivision of the E-type class with objects like Angelina, Eger, and Nereus. This group is not sampled by the current collection of aubrite meteorites. Interestingly, the reddened aubrite spectrum also provides a good match to the Steins VNIR spectrum

United States and Western Europe cooperation in planetary exploration

A framework was sought for U.S.-European cooperation in planetary exploration. Specific issues addressed include: types and levels of possible cooperative activities in the planetary sciences; specific or general scientific areas that seem most promising as the main focus of cooperative efforts; potential mission candidates for cooperative ventures; identification of special issues or problems for resolution by negotiation between the agencies, and possible suggestions for their resolutions; and identification of coordinated technological and instrumental developments for planetary missions

Asteroid target selection for the new Rosetta mission baseline: 21 Lutetia and 2867 Steins

Reproduced with permission. Copyright ESO. Article published by EDP Sciences and available at http://www.aanda.org.International audienceThe new Rosetta mission baseline to the comet 67P/Churyumov-Gerasimenko includes two asteroid fly-bys. To help in target selection we studied all the candidates of all the possible scenarios. Observations have been carried out at ESO-NTT (La Silla, Chile), TNG (Canaries), and NASA-IRTF (Hawaii) telescopes, in order to determine the taxonomy of all the candidates. The asteroid targets were chosen after the spacecraft interplanetary orbit insertion manoeuvre, when the available total amount of ΔV was known. On the basis of our analysis and the available of ΔV, we recommended to the ESA ScienceWorking Group the asteroids 21 Lutetia and 2867 Steins as targets for the Rosetta mission. The nature of Lutetia is still controversial. Lutetia's spectral properties may be consistent with a composition similar to carbonaceous chondrite meteorites. The spectral properties of Steins suggest a more extensive thermal history. Steins may have a composition similar to relatively rare enstatite chondrite/achondrite meteorites

One Year of COVID-19: Lessons Learned in a Hand Trauma Center

2020 will be remembered worldwide as the year of COVID-19 outbreak. The onset of this pandemic abruptly changed everybody's life and, in a particular manner, doctors' lives. Our hand surgery department became rapidly one of the first COVID-19-specialized wards in Italy, impacting considerably the authors' routines and activities. In this paper, the authors focus on how the demographics of patients with hand trauma changed and how they had to modify their activity. The authors retrospectively took into consideration all patients reaching their emergency department (ED) with hand trauma between 9 March 2020 (the day of the beginning of the first lockdown in Italy) and 8 March 2021 and compared them to those who reached the ED in the three previous years. Authors have analyzed the number of patients, their gender and age, the severity of their trauma, where the trauma occurred, the type of lesion, the percentage of patients who underwent surgery, and the percentage of patients who had an emergency admission. In the last year, the number of patients reaching the ED for a hand trauma has been reduced by two thirds (975 patients during the past year), the mean age of those patients has slightly increased, the severity of cases has increased, places of trauma and type of lesions have changed, and, lastly, the percentage of patients needing surgery who were admitted immediately has increased. This paper shows how the type of patients reaching the ED changed and discusses how surgeons evolved and modified their habits in treating those patients during the first lockdown and the year that followed