Beyond Point Masses. II. Non-Keplerian Shape Effects are Detectable in Several TNO Binaries
Abstract
About 40 transneptunian binaries (TNBs) have fully determined orbits with about 10 others being solved except for breaking the mirror ambiguity. Despite decades of study almost all TNBs have only ever been analyzed with a model that assumes perfect Keplerian motion (e.g., two point masses). In reality, all TNB systems are non-Keplerian due to non-spherical shapes, possible presence of undetected system components, and/or solar perturbations. In this work, we focus on identifying candidates for detectable non-Keplerian motion based on sample of 45 well-characterized binaries. We use MultiMoon, a non-Keplerian Bayesian inference tool, to analyze published relative astrometry allowing for non-spherical shapes of each TNB system's primary. We first reproduce the results of previous Keplerian fitting efforts with MultiMoon, which serves as a comparison for the non-Keplerian fits and confirms that these fits are not biased by the assumption of a Keplerian orbit. We unambiguously detect non-Keplerian motion in 8 TNB systems across a range of primary radii, mutual orbit separations, and system masses. As a proof of concept for non-Keplerian fitting, we perform detailed fits for (66652) Borasisi-Pabu, possibly revealing a , implying Borasisi (and/or Pabu) may be a contact binary or an unresolved compact binary. However, full confirmation of this result will require new observations. This work begins the next generation of TNB analyses that go beyond the point mass assumption to provide unique and valuable information on the physical properties of TNBs with implications for their formation and evolution.
Keywords
Cite
@article{arxiv.2403.12783,
title = {Beyond Point Masses. II. Non-Keplerian Shape Effects are Detectable in Several TNO Binaries},
author = {Benjamin C. N. Proudfoot and Darin A. Ragozzine and Meagan L. Thatcher and Will Grundy and Dallin J. Spencer and Tahina M. Alailima and Sawyer Allen and Penelope C. Bowden and Susanne Byrd and Conner D. Camacho and Gibson H. Campbell and Edison P. Carlisle and Jacob A. Christensen and Noah K. Christensen and Kaelyn Clement and Benjamin J. Derieg and Mara K. Dille and Cristian Dorrett and Abigail L. Ellefson and Taylor S. Fleming and N. J. Freeman and Ethan J. Gibson and William G. Giforos and Jacob A. Guerrette and Olivia Haddock and S. Ashton Hammond and Zachary A. Hampson and Joshua D. Hancock and Madeline S. Harmer and Joseph R. Henderson and Chandler R. Jensen and David Jensen and Ryleigh E. Jensen and Joshua S. Jones and Cameron C. Kubal and Jacob N. Lunt and Stephanie Martins and McKenna Matheson and Dahlia Maxwell and Timothy D. Morrell and McKenna M. Myckowiak and Maia A. Nelsen and Spencer T. Neu and Giovanna G. Nuccitelli and Kayson M. Reardon and Austin S. Reid and Kenneth G. Richards and Megan R. W. Robertson and Tanner D. Rydalch and Conner B. Scoresby and Ryan L. Scott and Zacory D. Shakespear and Elliot A. Silveira and Grace C. Steed and Christiana Z. Suggs and Garrett D. Suggs and Derek M. Tobias and Matthew L. Toole and McKayla L. Townsend and Kade L. Vickers and Collin R. Wagner and Madeline S. Wright and Emma M. A. Zappala},
journal= {arXiv preprint arXiv:2403.12783},
year = {2024}
}
Comments
Accepted to AJ