Showing papers on "Trojan published in 1991"

On the stability of the lagrangian points in the spatial restricted problem of three bodies

Abstract: The problem of stability of the Lagrangian equilibrium point of the circular restricted problem of three bodies is investigated in the light of Nekhoroshev-like theory. Looking for stability over a time interval of the order of the estimated age of the universe, we find a physically relevant stability region. An application of the method to the Sun-Jupiter and the Earth-Moon systems is made. Moreover, we try to compare the size of our stability region with that of the region where the Trojan asteroids are actually found; the result in such case is negative, thus leaving open the problem of the stability of these asteroids.

The 1990 MB: The first Mars Trojan

Abstract: Asteroid 1990 MB was discovered during the course of the Mars and Earth-crossing Asteroid and Comet Survey. An orbit based on a 9-day arc and the asteroid's location near Mars L5 longitude led to speculation that it might be in 1:1 resonance with Mars, analogous to the Trojan asteroids of Jupiter. Subsequent observations strengthened the possibility, and later calculations confirmed it. The most recent orbit shows that the asteroid's semimajor axis is very similar to that of Mars.

Computer viruses

Abstract: This paper presents an overview of the main categories of malicious programs known as Trojan horses, viruses, bacteria, worms, and logic bombs. The focus is on their general behavior and the properties seen in their implementations rather than the ultimate effects or their intended destructive behavior. Possible preventive measures are also discussed. >

On the dynamical structure of the trojan group of asteroids

Abstract: Using a semi-analytical approach, domains of possible motion for Trojan asteroids have been established. It is shown that stable librating motion is possible for both high inclination and high eccentricity. frequency distributions have also been produced for real Trojan asteroids, against differing libration amplitudes and libration periods. Using a semi-analytical model described by Yoshikawa (1990), we consider the possible motion of massless Trojan asteroids, that is asteroids situated close to the 1:1 resonance region with Jupiter, which is assumed to be moving on its actual elliptic orbit. The asteroids are allowed to move on non-circular orbits in three dimensions. For

On the discovery of the Trojan object 4060 = 1987 YT1 = Deipylos

Abstract: During an extensive search in 1987 for new Trojan objects with the ESO Schmidt telescope, two new Trojans were discovered One of these objects, 1987 YT1, was recovered at the subsequent dark run at ESO by DEBEHOGNE with the GPO instrument used in the astrographic mode New observations in 1989 by ELST at the GPO and ESO Schmidt led to definite numbering (4060) and naming (Deipylos) of this Trojan object The orbit is calculated starting from the discovery 1987/88 observations using a classic Gaussian procedure The orbit is subsequently improved by the method of the variation of the geocentric distances These orbital elements are compared with the osculating elements which have been obtained from orbit calculation using all available observations (1942–1989)