Presentation #512.05D in the session “Asteroid Hazards and Planetary Defense”.
Apophis is a Potentially Hazardous Asteroid (PHA) that will approach the Earth in 2029 at about 40,000 km, which is the region of the geosynchronous orbit. Here, we explore its surface characteristics and dynamical nearby environment. We considered the irregular shape of the Apophis as an uniform density polyhedra (Brozović et al. 2018), with a bulk density that might have the significantly different values of 1.29 g cm-3, 2.2 g cm-3, 3.2 g cm-3, and 3.5 g cm-3 (Brozović et al. 2018, Binzel et al. 2007, Farnocchia et al. 2013) and a rotational period of 27.38 h (Souchay et al. 2018). We analyze geometric quantities such as the geometric altitude and tilt angle, as well as physical properties related to the geopotential (e.g. geopotential, accelerations, slope angle, and among others). To explore the dynamical nearby environment, we compute the zero-velocity curves, the equilibrium points, and also their topological classification. Additionally, we performed numerical simulations of massless particles in a region encompassing the equilibrium points taking into account the rotating body’s gravity and the solar radiation pressure with the goal of identifying stable regions that might have small debris.
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES) - Finance Code 001, CNPQ (Proc. 305210/2018-1) and FAPESP (Proc. 2016/24561-0 and Proc. 2019/23963-5).
Binzel, R. P., et al. “Spectral properties and composition of potentially hazardous Asteroid (99942) Apophis.” DPS. 2007.
Brozović, M., et al. “Goldstone and Arecibo radar observations of (99942) Apophis in 2012-2013.” Icarus 300 (2018): 115-128.
Farnocchia, Davide, et al. “Yarkovsky-driven impact risk analysis for asteroid (99942) Apophis.” Icarus 224.1 (2013): 192-200.
Souchay, J., et al. “Changes of spin axis and rate of the asteroid (99942) Apophis during the 2029 close encounter with Earth: A constrained model.” Astronomy & Astrophysics 617 (2018): A74.