Note about the impact possibilities of asteroid (99942) Apophis

TL;DR

This paper uses Monte Carlo orbit cloning to assess the impact risk of asteroid Apophis, finding a slight increase in the probability of Earth impact in 2036 based on recent observational data.

Contribution

It applies Monte Carlo orbit cloning to refine impact probability estimates for Apophis using observational data from 2004 to 2008.

Findings

Impact probability in 2036 increased to 4.5×10^{-6}

Closest approach in 2029 is approximately 5.921 Earth radii

Results align with previous studies by Chesley et al.

Abstract

The Monte Carlo method of the nominal orbit clonning was applied to the case of 99942 Apophis, the asteroid from the Aten group. Calculations based on observations from the time interval of 2004 03 15 - 2008 01 09 have shown that the asteroid will pass near Earth in 2029 at the minimum distance of 5.921 \pm 0.042 R_{Earth}, what implies that the likelihood that Apophis strikes the planet at 2036 April 13 increased to 4.5\times 10^{-6} (from about 6\times 10^{-7} previously announced by us in Paper~I (Krolikowska, Sitarski and Soltan, 2009, MNRAS 399, 1964). This value is identical with that given by Chesley, Baer, and Monet (2010, Icarus, in press).