Academic literature on the topic 'Atira asteroids'

Abstract The rotational reflex velocity (RRV) method was proposed by Heinze and Metchev in 2015 and was used to measure the distances of main-belt asteroids (MBAs). Later, Lin et al. generalized this method using spherical astronomy in 2016. The method measures the distances of MBAs using the observations from a single ground-based telescope over two nights. We refined this method and extend it further to the distance measurement of near-Earth asteroids (NEAs). In practice, we measure the distance of the potentially hazardous asteroid (99942) Apophis from the acquired CCD frames using the newly refined method. According to the requirement of the newly refined method, we also simulate the distance measurements of the four typical NEAs, (1221) Amor, (1862) Apollo, (2062) Aten, and (163693) Atira, on their discovery dates and follow-up dates. The measurement results of Apophis based on the newly refined RRV method show that the mean relative errors for the independent exposure frames on the successive two nights is ∼0.08% (about a factor of 2 improvement in comparison with the research of Lin et al.) compared with the distance from JPL ephemeris. Our simulation results also show that this refined method can accurately and precisely measure the distances of newly discovered NEAs in an astrometric way without performing orbital determination. The accurate and precise distances of newly discovered asteroids help us to conveniently evaluate their impact risks within a shorter time, leaving us more time to take defense precautions.

ABSTRACT This study is an orbital analysis of the interesting Mars-crossing asteroids (MCAs), also known as Mars-crosser (MC) asteroids or Mars-crossers (MCs). We computed that after 100 million years (Myr), approximately 66 ${{\ \rm per\ cent}}$ of all known MCs are ejected out of the Solar System by collision with the Sun, the planets, Ceres, Pallas, Vesta, or Hygiea. The rate of MC migration is high. Thus, this population of MCs would be supplied by just as many asteroids from outside the Solar System. We estimated the rate at which near-Earth objects were created from MCs throughout a 100 Myr period, with Atiras accounting for nearly 3 ${{\ \rm per\ cent}}$ of these objects, over 2 ${{\ \rm per\ cent}}$ were Atens, nearly 7.5 ${{\ \rm per\ cent}}$ were Apollos, approximately 9${{\ \rm per\ cent}}$ were Amors, and nearly 0.4 ${{\ \rm per\ cent}}$ became Centaurs. These results were calculated with 10 000 yr output intervals. Furthermore, 0.028${{\ \rm per\ cent}}$ of all the starting MCs were in retrograde orbits for at least 10 000 yr. We found that majority of the remaining MCs have migrated into the region of three asteroid families: Phocaea, Hungaria, and Flora. We calculated a small but significant influence of Ceres, Pallas, Vesta, and Hygiea on the orbital evolution of the MCs. From the AstDys catalogue, we found that the largest number of studied numbered MCs have their Lyapunov time (LT) in the range 2–4 kyr. Using the orbfit software, we computed the LT of selected MCs in retrograde orbits, and obtained an LT of between 540 yr (asteroid 2016 DR1) and 71 000 yr (asteroid 42887 1999 RV155).

ABSTRACT Orbiting the Sun at an average distance of 0.59 au and with the shortest aphelion of any known minor body, at 0.77 au, the Atira-class asteroid 2019 AQ3 may be an orbital outlier or perhaps an early indication of the presence of a new population of objects: those following orbits entirely encompassed within that of Venus, the so-called Vatiras. Here, we explore the orbital evolution of 2019 AQ3 within the context of the known Atiras to show that, like many of them, it displays a present-day conspicuous coupled oscillation of the values of eccentricity and inclination, but no libration of the value of the argument of perihelion with respect to the invariable plane of the Solar system. The observed dynamics is consistent with being the result of the combined action of two dominant perturbers, the Earth–Moon system and Jupiter, and a secondary one, Venus. Such a multiperturber-induced secular dynamics translates into a chaotic evolution that can eventually lead to a resonant behaviour of the Lidov–Kozai type. Asteroid 2019 AQ3 may have experienced brief stints as a Vatira in the relatively recent past and it may become a true Vatira in the future, outlining possible dynamical pathways that may transform Atiras into Vatiras and vice versa. Our results strongly suggest that 2019 AQ3 is only the tip of the iceberg: a likely numerous population of similar bodies may remain hidden in plain sight, permanently confined inside the Sun’s glare.