Search

This paper presents synthetic observations of long-lived coorbiting asteroids of Mercury, Venus, the Earth and Mars. Our sample is constructed by taking the limiting semimajor axes, differential longitudes and inclinations for long-lived stability provided by simulations. The intervals are randomly populated with values to create initial conditions. These orbits are re-simulated to check that they are stable and then re-sampled every 2.5 yr for 1 Myr. The Mercurian sample only contains horseshoe orbits, whereas the Martian sample only contains tadpoles. For both Venus and the Earth, the greatest concentration of objects on the sky occurs close to the classical Lagrange points at heliocentric ecliptic longitudes of 60° and 300°. The distributions are broad especially if horseshoes are present in the sample. The FWHM in heliocentric longitude for Venus is 325° and for the Earth is 328°. The mean and most common velocity of these coorbiting satellites coincides with the mean motion of the parent planet, but again the spread is wide with an FWHM of 27.8 and 21.0 arcsec h[sup -1] for Venus and the Earth, respectively. For Mars, the greatest concentration on the sky occurs at heliocentric ecliptic latitudes of ±12°. The peak of the velocity distribution occurs at 65 arcsec h[sup -1], significantly less than the Martian mean motion, while its FWHM is 32.3 arcsec h[sup -1]. The case of Mercury is the hardest of all, as the greatest concentrations occur at heliocentric longitudes of 16°.0 and 348°.5 and so are different from the classical values. The fluctuating eccentricity of Mercury means that these objects can have velocities exceeding 1000 arcsec h[sup -1] although the most common velocity is 459 arcsec h[sup -1], which is much less than the Mercurian mean motion. A variety of search strategies are discussed, including wide-field CCD imaging, space satellites such as the Global Astrometry Interferometer for Astrophysics (GAIA), ground-based surveys like the Sloan Digital Sky Survey (SDSS), as well as infrared cameras and space-borne coronagraphs. [ABSTRACT FROM AUTHOR]

Ensembles of in-plane and inclined orbits in the vicinity of the Lagrange points of the terrestrial planets are integrated for up to 100 Myr. The integrations incorporate the gravitational effects of the Sun and the eight planets (Pluto is neglected). Mercury is the least promising planet , as it is unable to retain tadpole orbits over 100-Myr time-scales. Mercurian Trojans probably do not exist, although there is evidence for long-lived, corotating horseshoe orbits with small inclinations. Both Venus and the Earth are much more promising, as they possess rich families of stable tadpole and horseshoe orbits. Our survey of Trojans in the orbital plane of Venus is undertaken for 25 Myr. Some 40 per cent of the survivors are on tadpole orbits. For the Earth, the integrations are pursued for 50 Myr. The stable zones in the orbital plane are larger for the Earth than for Venus, but fewer of the survivors (∼20 per cent) are tadpoles. Both Venus and the Earth also have regions in which inclined test particles can endure near the Lagrange points. For Venus, only test particles close to the orbital plane are stable. For the Earth, there are two bands of stability, one at low inclinations and one at moderate inclinations The inclined test particles that evade close encounters are primarily moving on tadpole orbits. Two Martian Trojans (5261 Eureka and 1998 VF31) have been discovered over the last decade and both have orbits moderately inclined to the ecliptic (20°.3 and 31°.3 respectively). Our survey of in-plane test particles near the Martian Lagrange points shows no survivors after 60 Myr. Low-inclination test particles do not persist, as their inclinations are quickly increased until the effects of a secular resonance with Jupiter cause destabilization. Numerical integrations of inclined test particles for time-spans of 25 Myr show stable zones for inclinations between 14° and 40°. However, there is a strong linear resonance with Jupiter that destabilizes a narrow band of inclinations at ∼29°. Both 5261 Eureka and 1998 VF31 lie deep within the stable zones, which suggests that they may be of primordial origin. [ABSTRACT FROM AUTHOR]

High-resolution simulations are used to map out the detailed structure of two long-lived stable belts of asteroid orbits in the inner Solar system. The Vulcanoid belt extends from 0.09 to 0.20 au, though with a gaps at 0.15 and 0.18 au corresponding to de-stabilizing mean motion resonances with Mercury and Venus. As collisional evolution proceeds slower at larger heliocentric distances, km-sized or larger Vulcanoids are most likely to be found in the region between 0.16 and 0.18 au. The optimum location to search is at geocentric ecliptic longitudes 9° ≤ ...[sub g] ≤ 10° and latitudes Β[sub g] < 1deg;. Dynamically speaking, the Earth-Mars belt between 1.08 and 1.28 au is a stable repository for asteroids on nearly circular orbits. It is interrupted at 1.21 au owing to the 3:4 commensurability with the Earth, while secular resonances with Saturn are troublesome beyond 1.17 au. These detailed maps of the fine structure of the belts can be used to plan search methodologies. Strategies for detecting members of the belts are discussed, including the use of infrared wide-field imaging with VISTA, and forthcoming European Space Agency satellite missions such as GAIA and BepiColombo. [ABSTRACT FROM AUTHOR]