About

backtracks is a python package to fit relative astrometry with background helical motion tracks, to discern directly imaged planets :ringed_planet: from contaminant sources :dizzy: :star:

The code is written and developed by Gilles Otten (@gotten), William Balmer (@wbalmer), and Tomas Stolker (@tomasstolker).

Attribution

If you use backtracks in your published work, please cite our Zenodo entry (here), and provide a footnote/acknowledgement linking to our package. An example bibtex citation is included below, but you may wish to cite a specific version of the package via zenodo instead. Thank you!

@software{backtracks_code,
     author       = {William O. Balmer and
                     Gilles P. P. L. Otten and
                     Tomas Stolker},
     title        = {backtracks: a python package to compare relative astrometry with background helical motion: v0.6},
     month        = feb,
     year         = 2025,
     publisher    = {Zenodo},
     version      = {v0.6},
     doi          = {10.5281/zenodo.14838369},
     url          = {https://doi.org/10.5281/zenodo.14838369},
   }

Details

• eDR3 Distance prior summary file from Bailer-Jones et al. (2021).

• Example of HD 131399Ab uses data from Wagner et al. (2022) and Nielsen et al. (2017). Thank you to Kevin Wagner for providing the latest astrometry!

• Log-likelihood and some utility functions borrowed heavily from orbitize! (BSD 3-clause).

• PPF of multivariate normal borrowed from pints (BSD 3-clause).