Near-Earth asteroid 2012 DA14 made its closest approach on February 15, 2013, when it passed at a distance of 27,700 km from the Earth’s surface. It was the first time an asteroid of moderate size was predicted to approach that close to the Earth, becoming bright enough to permit a detailed study from ground-based telescopes. Asteroid 2012 DA14 was poorly characterized before its closest approach. The main objective of this work was to obtain new and valuable data to better understand its physical properties, and to evaluate the effects of such a close approach on the object. We acquired data using several telescopes on four Spanish observatories: the 10.4 m Gran Telescopio Canarias (GTC) and the 3.6 m Telescopio Nazionale Galileo (TNG), both in the El Roque de los Muchachos Observatory (ORM, La Palma); the 2.2 m CAHA telescope, in the Calar Alto Observatory (Almería); the f/3 0.77 m telescope in the La Hita Observatory (Toledo); and the f/8 1.5 m telescope in the Sierra Nevada Observatory (OSN, Granada). We obtained visible and near-infrared color photometry, visible spectra and time-series photometry. Visible spectra together with visible and near-infrared color photometry of 2012 DA14 show that the object can be classified as an L-type asteroid, a rare spectral type among the asteroid population, with a composition similar to that of carbonaceous chondrites. The time-series photometry provides a rotational period of 8.95 ± 0.08 h after the closest approach, and there are indications that the object suffered a spin-up during this event. The large amplitude of the light curve suggests that the object is very elongated and irregular, with an equivalent diameter of around 18 m. We obtain an absolute magnitude of HR = 24.5 ± 0.2, corresponding to HV = 25.0 ± 0.2 in V. The GTC photometry also gives HV = 25.29 ± 0.14. Both values agree with the value listed at the Minor Planet Center (MPC) shortly after discovery, although HV is very sensitive to the slope parameter G used to correct for phase angle. From the absolute photometry, together with some constraints on size and shape, we compute a geometric albedo of pV = 0.44 ± 0.20, which is slightly above the range of albedos known for L-type asteroids (0.082−0.405).
It may interest you
Some galaxies in the Universe display beautiful and appealing features known as "spiral arms". However, not all galaxies show spiral arms in the same manner. Among the variety of cases the Large Magellanic Cloud (LMC), a dwarf galaxy infalling towards the Milky Way, stands out. The LMC is the prototype of an entire family of galaxies, the Magellanic Spirals that are characterised by the presence of a barred stellar structure near their centres and a single spiral arm. Spiral patterns can form after galactic collisions, with subsequent star formation piling up in these arms. Nevertheless, weAdvertised on
The solar coronal heating problem originated almost 80 years ago and remains unsolved. A plausible explanation lies in mechanisms based on magnetic wave energy dissipation. Currently, several linear and nonlinear wave damping models have been proposed. The advent of space instrumentation has led to the creation of catalogues containing the properties of a large number of loop oscillation events. When the damping ratio of the oscillations is plotted against their oscillation amplitude, the data are scattered forming a cloud with a triangular shape. Larger amplitudes correspond in general toAdvertised on
Can neural networks distinguish computer simulated galaxy images from observed galaxies? This is the question that has been addressed in this work. For years, reproducing the morphological diversity of galaxies has been a problem for cosmological simulations. The new generation of simulations, such as Illustris TNG, are becoming more and more realistic. But enough to fool a neural network? In this work it is shown that it does not. Using unsupervised deep generative models, it is shown that, despite the fact that realism increases greatly in the last generation of simulations and withAdvertised on