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de la Fuente Marcos R.,Apartado de Correos 3413 | de la Fuente Marcos C.,Apartado de Correos 3413
Astronomische Nachrichten | Year: 2015

The detection of high-energy astro-physical neutrinos of extraterrestrial origin by the IceCube neutrino observatory in Antarctica has opened a unique window to the cosmos that may help to probe both the distant Universe and our cosmic backyard. The arrival directions of these high-energy events have been interpreted as uniformly distributed on the celestial sphere. Here, we revisit the topic of the putative isotropic angular distribution of these events applying Monte Carlo techniques to investigate a possible anisotropy. A modest evidence for anisotropy is found. An excess of events appears projected towards a section of the Local Void, where the density of galaxies with radial velocities below 3000 km s-1 is rather low, suggesting that this particular group of somewhat clustered sources are located either very close to the Milky Way or perhaps beyond 40 Mpc. The results of further analyses of the subsample of southern hemisphere events favour an origin at cosmological distances with the arrival directions of the events organized in a fractal-like structure. Although a small fraction of closer sources is possible, remote hierarchical structures appear to be the main source of these very energetic neutrinos. Some of the events may have their origin at the IBEX ribbon. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

de la Fuente Marcos C.,Apartado de Correos 3413 | de la Fuente Marcos R.,Apartado de Correos 3413 | Aarseth S.J.,University of Cambridge
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2016

The Planet Nine hypothesis has now enough constraints to deserve further attention in the form of detailed numerical experiments. The results of such studies can help us improve our understanding of the dynamical effects of such a hypothetical object on the extreme trans-Neptunian objects or ETNOs and perhaps provide additional constraints on the orbit of Planet Nine itself. Here, we present the results of direct N-body calculations including the latest data available on the Planet Nine conjecture. The present-day orbits of the six ETNOs originally linked to the hypothesis are evolved backwards in time and into the future under some plausible incarnations of the hypothesis to investigate if the values of several orbital elements, including the argument of perihelion, remain confined to relatively narrow ranges. We find that a nominal Planet Nine can keep the orbits of (90377) Sedna and 2012 VP113 relatively well confined in orbital parameter space for hundreds of Myr, but it may make the orbits of 2004 VN112, 2007 TG422 and 2013 RF98 very unstable on time-scales of dozens of Myr, turning them retrograde and eventually triggering their ejection from the Solar system. Far more stable orbital evolution is found with slightly modified orbits for Planet Nine. © 2016 The Authors.

De La Fuente Marcos C.,Apartado de Correos 3413 | De La Fuente Marcos R.,Apartado de Correos 3413 | Aarseth S.J.,University of Cambridge
Astrophysical Journal | Year: 2015

On 2013 February 15 a small asteroid rammed against the atmosphere above the region of Chelyabinsk in Russia, producing the most powerful superbolide since the Tunguska event in 1908. Lacking proper astrometric observations, the pre-impact orbit of this object has been determined using videos, satellite images, and pure geometry. Unfortunately, more than two years after the event, the published estimates vary so much that there is no clear orbital solution that could be used to investigate the origin of the impactor and the existence of dynamically, or perhaps even genetically, related asteroids. Here, we revisit this topic using a full N-body approach. A robust statistical test is applied to published solutions to discard those unable to produce a virtual impact at the observed time (03:20:20.8 ± 0.1 s UTC). The same N-body methodology and the latest ephemerides are used to compute a new orbital solution: a = 1.6247 AU, e = 0.5318, i = 3.°9750, Ω = 326.°4607, and ω = 109.°7012. This new solution - which has an impact probability >0.99999 and uncertainties in time and space of 0.2 s and 6 km, respectively - is utilized to explore the past orbital evolution of the impactor as well as the presence of near-Earth objects moving in similar paths. A dynamical link between asteroid 2011 EO40 and the Chelyabinsk impactor is confirmed. Alternative orbital solutions are extensively explored. © 2015. The American Astronomical Society. All rights reserved..

De La Fuente Marcos C.,Apartado de Correos 3413 | De La Fuente Marcos R.,Apartado de Correos 3413
Monthly Notices of the Royal Astronomical Society | Year: 2015

Minor bodies trapped in 1:1 co-orbital resonances with a host planet could be relevant to explain the origin of captured satellites. Among the giant planets, Uranus has one of the smallest known populations of co-orbitals, three objects, and all of them are short-lived. Asteroid 2015 DB216 has an orbital period that matches well that of Uranus, and here we investigate its dynamical state. Direct N-body calculations are used to assess the current status of this object, reconstruct its immediate dynamical past, and explore its future orbital evolution. A covariance matrixbased Monte Carlo scheme is presented and applied to study its short-term stability. We find that 2015 DB216 is trapped in a temporary co-orbital resonance with Uranus, the fourth known minor body to do so. A detailed analysis of its dynamical evolution shows that it is an unstable but recurring co-orbital companion to Uranus. It currently follows an asymmetric horseshoe trajectory that will last for at least 10 kyr, but it may remain inside Uranus' co-orbital zone for millions of years. As in the case of other transient Uranian co-orbitals, complex multibody ephemeral mean motion resonances trigger the switching between the various resonant coorbital states. The new Uranian co-orbital exhibits a secular behaviour markedly different from that of the other known Uranian co-orbitals because of its higher inclination, nearly 38°. Given its rather unusual discovery circumstances, the presence of 2015 DB216 hints at the existence of a relatively large population of objects moving in similar orbits. © 2015 The Authors.

de la Fuente Marcos C.,Apartado de Correos 3413 | de la Fuente Marcos R.,Apartado de Correos 3413
Astrophysics and Space Science | Year: 2016

It is widely accepted that a quasi-steady-state flux of minor bodies moving in and out of the co-orbital state with the Earth may exist. Some of these objects are very good candidates for future in situ study due to their favourable dynamical properties. In this paper, we show that the recently discovered near-Earth asteroids 2015  (Formula presented.) , 2015 YA and 2015  (Formula presented.) are small transient Earth co-orbitals. These new findings increase the tally of known Earth co-orbitals to 17. The three of them currently exhibit asymmetric horseshoe behaviour subjected to a Kozai resonance and their short-term orbital evolution is rather unstable. Both 2015 YA and 2015  (Formula presented.) may leave Earth’s co-orbital zone in the near future as they experience close encounters with Venus, the Earth-Moon system and Mars. Asteroid 2015  (Formula presented.) may have remained in the vicinity of, or trapped inside, the 1:1 mean motion resonance with our planet for many thousands of years and may continue in that region for a significant amount of time into the future. © 2016, Springer Science+Business Media Dordrecht.

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