The rvfit Code: A Detailed Adaptive Simulated Annealing Code for Fitting Binaries and Exoplanets Radial Velocities

TL;DR

The rvfit code employs an Adaptive Simulated Annealing method to efficiently fit radial velocity data of binaries and exoplanets, avoiding local minima and not requiring initial parameter guesses.

Contribution

It introduces a new global minimization code for radial velocity fitting that improves convergence and usability over traditional methods.

Findings

Successfully fits synthetic and real data sets.

Accurately recovers orbital parameters and uncertainties.

Demonstrates advantages over previous fitting routines.

Abstract

The fitting of radial velocity curves is a frequent procedure in binary stars and exoplanet research. In the majority of cases the fitting routines need to be fed with a set of initial parameter values and priors from which to begin the computations and their results can be affected by local minima. We present a new code, the rvfit code, for fitting radial velocities of stellar binaries and exoplanets using an Adaptive Simulated Annealing (ASA) global minimization method, which fastly converges to a global solution minimum without the need to provide preliminary parameter values. We show the performance of the code using both synthetic and real data sets: double-lined binaries, single-lined binaries, and exoplanet systems. In all examples the keplerian orbital parameters fitted by the rvfit code and their computed uncertainties are compared with literature solutions. Finally, we provide the source code with a working example and a detailed description on how to use it.