Physics of Eclipsing Binaries. V. General Framework for Solving the Inverse Problem

Abstract

PHOEBE 2 is a Python package for modeling the observables of eclipsing star systems, but until now has focused entirely on the forward-model -that is, generating a synthetic model given fixed values of a large number of parameters describing the system and the observations. The inverse problem, obtaining orbital and stellar parameters given observational data, is more complicated and computationally expensive as it requires generating a large set of forward-models to determine which set of parameters and uncertainties best represent the available observational data. The process of determining the best solution and also of obtaining reliable and robust uncertainties on those parameters often requires the use of multiple algorithms, including both optimizers and samplers. Furthermore, the forward-model of PHOEBE has been designed to be as physically robust as possible, but is computationally expensive compared to other codes. It is useful, therefore, to use whichever code is most efficient given the reasonable assumptions for a specific system, but learning the intricacies of multiple codes presents a barrier to doing this in practice. Here we present the 2.3 release of PHOEBE (publicly available from http://phoebe-project.org) which introduces a general framework for defining and handling distributions on parameters, and utilizing multiple different

A black hole detected in the young massive LMC cluster NGC 1850

“…By using the latest version of PHOEBE (v2.3) (Conroy et al 2020), a software for modelling the light and radial velocity curves of binaries, we were able to put further constraints on the system and also confirm previous findings. Namely: 1) this system is, in fact, not an eclipsing binary as no eclipses are present in the light curves.…”

Parameters of the eclipsing binary α Draconis observed by TESS and SONG

“…This called for an additional step in the modeling with a more robust setup. For this purpose, we used P , whose latest release (Conroy et al 2020) supports fitting, including sampling with MCMC and adding distributions as priors to any model parameter. P is a powerful binary modelling software written in P , which aims to provide a full physical description of both stars and the binary orbit.…”

A tidally tilted sectoral dipole pulsation mode in the eclipsing binary TIC 63328020

“…We now proceed to analyse the system parameters via simultaneous fitting of the TESS orbital light curve as well as the RV points using the next-generation Wilson-Devinney code PHOEBE2 we used was defined by Choi et al (2016) as: X = 0.7154, Y = 0.2703, and Z = 0.0142 (taken from Asplund et al 2009). (Prša et al 2016;Horvat et al 2018;Conroy et al 2020;Jones et al 2020). First, we removed the pulsations from the light curve.…”