Das neue Paper von Zuluaga, Ferrin, und Geens gibt es hier als PDF
PDF-DownloadThe orbit of the Chelyabinsk event impactor as reconstructed from amateur and public footage (7.3.13)
Jorge I. Zuluaga (IF/FCEN, UdeA), Ignacio Ferrin (IF/FCEN, UdeA), Stefan Geens (Ogle Earth)
A ballistic reconstruction of a meteoroid orbit can be made if enough information is available about its trajectory inside the atmosphere. A few methods have been devised in the past and used in several cases to trace back the origin of small impactors. On February 15, 2013, a medium-sized meteoroid hit the atmosphere in the Chelyabinsk region of Russia, causing damage in several large cities. The incident, the largest registered since the Tunguska event, was witnessed by many thousands and recorded by hundreds of amateur and public video recording systems. The amount and quality of the information gathered by those systems is sufficient to attempt a reconstruction of the trajectory of the impactor body in the atmosphere, and from this the orbit of the body with respect to the Sun. Using amateur and public footage taken in four different places close to the event, we have determined precisely the properties of the entrance trajectory and the orbit of the Chelyabinsk event impactor. We found that the object entered the atmosphere at a velocity ranging from 16.0 to 17.4 km/s in a grazing trajectory, almost directly from the east, with an azimuth of velocity vector of 285$^o$, and with an elevation of 15.8$^o$ with respect to the local horizon. The orbit that best fits the observations has, at a 95% confidence level, a semi-major axis a = 1.26$\pm$0.05 AU, eccentricity e = 0.44$\pm$0.03, argument of perihelion $\omega$=95.5$^o\pm2^o$ and longitude of ascending node $\Omega$= 326.5$^o\pm0.3^o$. Using these properties the object can be classified as belonging to the Apollo family of asteroids. The absolute magnitude of the meteoroid was H= 25.8, well below the threshold for its detection and identification as a Potential Hazardous Asteroid (PHA). This result would imply that present efforts intended to detect and characterize PHAs are incomplete.
Orbital elements of the impactor in the a-e diagram compared with the three main families of Near Earth Asteroids.
FOTO-LINKMagnitude of the impactor for the few days previous to impact.
FOTO-LINKAltazimuth-footprint diagram for the four vantage points used in our reconstruction and for the best-fit trajectory. The footprint of the trajectory estimated by the group of the Astronomical Institute of the Czech Academy of Sciences (BSS2013) and NASA (YC2013) is also shown.
FOTO-LINKDie neueste GoogleEarth KMZ-Datei (7.3.13) gibt es hier zum Download:
KMZ-DownloadQuelle der Daten und der Tabelle unten (atmospheric trajectory)
