Predicting Closest Approach of Apophis

MATLAB script for predicting close approaches between the asteroid Apophis and Earth.

This MATLAB script demonstrates how to interact with a typical asteroid ephemeris file created with the JPL Horizons System located at https://ssd.jpl.nasa.gov/horizons/app.html#/.

Both the asteroid and planetary ephmeris implemented in this script use JPL/NAIF MICE routines to evaluate the ephemerides. Platform-specific versions (Windows, Mac, etc.) of the required MICE mex file are available at https://naif.jpl.nasa.gov/naif/.

This MATLAB script uses Brent's method of minimization to predict close approach (minimum distance) between Earth and Apophis. The software will request a close approach search duration in days. It will also allow the user to enforce a minimum distance criterion in units of Astronomical Units.

For example, here are close approach conditions for the Apophis encounter in April 2029.

time and conditions at closest approach

=======================================

calendar date 13-Apr-2029

TDB time 21:46:12.683

TDB Julian date 2462240.40709124

geocentric distance 0.00025409 AU

geocentric distance 38011.48712644 kilometers

It is suggested that users create a unique directory for this application and copy all files from the zip archive to this directory. Log in to this directory from within MATLAB and run the script from there by typing cae2apophis at the command line.

PDF documentation for the Mathworks File Exchange submission "Closest Approach Between the Earth and Heliocentric Objects" is included.

https://www.mathworks.com/matlabcentral/fileexchange/39270-closest-approach-between-the-earth-and-heliocentric-objects?s_tid=srchtitle