ASE: Amateur Search for Exoplanets via Radial Velocity Analysis

ASE is a MatLab application that incorporates MERCURY6 FORTRAN code for automatic search of exoplanet orbital fits to radial velocity data using genetic algorithms.

Inspired by an article “Virtual Planet Sleuths” by Gregory P. Laughlin published in October 2006 issue of Sky & Telescope magazine, as astronomy amateurs, we wanted to get a better understanding of processes behind the process of exoplanet search via radial velocity analysis. Practically, we have decided to write an application from scratch which would be automatically analysing radial velocity data sets and provide the user with orbit characteristics of underlying exoplanets orbiting a particular star. ASE, for automatizing the search, applies optimization and minimization algorithms such as GA, MGA (SQP) and similiar. Playing around with publicily available RV data sets produces amazing results. ASE evolves from a simple Excel-based application into a stand-alone application as an amateur approach to astrophysics, astrostatistics, astrodynamics and celestial mechanics.

Currently ASE is an application which allows to:

  • Search exoplanet orbital parameters (models) using Genetic Algorithms.
  • Polish models with Levenberg-Marquardt and Multiobjective Goal Attainment (MGA) – sequential quadratic programming (SQP) methods.
  • Quickly search periods with Lomb-Scargle periodogram and averaging filter with automatic Pmin/Pmax search constraint detection by FWHM of the peak.
  • Execute batch runs to search for the best fit (model).
  • Execute multicomponent GA scans: analyzing residuals and accumulative scans (described below in standard procedures in detail).
  • Do quick bootstrap analysis to detect model uncertainities, standard distribution, and build histograms of planet’s parameter distributions.
  • Linear detrending of RV data set.
  • Orbital stability checks with the following N-body algorithms: second-order mixed-variable symplectic (MVS), general Bulirsch-Stoer, Conservative Bulirsch-Stoer, Everhart’s RA15 (RADAU) and Hybrid symplectic/Bulirsch-Stoer integrator – via John E. Chambers MERCURY6, controlled from ASE.

Link to ASE project page and source code

[alert type=”blue” textalign=”left”]ASE uses MatLab and FORTRAN code that may be obsolete.[/alert]