Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs
Abstract
Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these small bodies and has presented exciting results. These observations can provide precise profiles of the involved body, allowing an accurate determination of its size and shape. The goal is to show that even single-chord detections of TNOs allow us to measure their milliarcsecond astrometric positions in the reference frame of the Gaia second data release (DR2). Accurated ephemerides can then be generated, allowing predictions of stellar occultations with much higher reliability. We analyzed data from stellar occultations to obtain astrometric positions of the involved bodies. The events published before the Gaia era were updated so that the Gaia DR2 catalog is the reference. Previously determined sizes were used to calculate the position of the object center and its corresponding error with respect to the detected chord and the International Celestial Reference System (ICRS) propagated Gaia DR2 star position. We derive 37 precise astrometric positions for 19 TNOs and 4 Centaurs. Twenty-one of these events are presented here for the first time. Although about 68\% of our results are based on single-chord detection, most have intrinsic precision at the submilliarcsecond level. Lower limits on the diameter and shape constraints for a few bodies are also presented as valuable byproducts. Using the Gaia DR2 catalog, we show that even a single detection of a stellar occultation allows improving the object ephemeris significantly, which in turn enables predicting a future stellar occultation with high accuracy. Observational campaigns can be efficiently organized with this help, and may provide a full physical characterization of the involved object.
Cite
@article{arxiv.2010.12708,
title = {Stellar occultations enable milliarcsecond astrometry for Trans-Neptunian objects and Centaurs},
author = {F. L. Rommel and F. Braga-Ribas and J. Desmars and J. I. B. Camargo and J. L. Ortiz and B. Sicardy and R. Vieira-Martins and M. Assafin and P. Santos-Sanz and R. Duffard and E. Fernández-Valenzuela and J. Lecacheux and B. E. Morgado and G. Benedetti-Rossi and A. R. Gomes-Júnior and C. L. Pereira and D. Herald and W. Hanna and J. Bradshaw and N. Morales and J. Brimacombe and A. Burtovoi and T. Carruthers and J. R. de Barros and M. Fiori and A. Gilmore and D. Hooper and K. Hornoch and C. Jacques and T. Janik and S. Kerr and P. Kilmartin and Jan Maarten Winkel and G. Naletto and D. Nardiello and V. Nascimbeni and J. Newman and A. Ossola and A. Pál and E. Pimentel and P. Pravec and S. Sposetti and A. Stechina and R. Szákats and Y. Ueno and L. Zampieri and J. Broughton and J. B. Dunham and D. W. Dunham and D. Gault and T. Hayamizu and K. Hosoi and E. Jehin and R. Jones and K. Kitazaki and R. Komžík and A. Marciniak and A. Maury and H. Mikuž and P. Nosworthy and J. Fábrega Polleri and S. Rahvar and R. Sfair and P. B. Siqueira and C. Snodgrass and P. Sogorb and H. Tomioka and J. Tregloan-Reed and O. C. Winter},
journal= {arXiv preprint arXiv:2010.12708},
year = {2021}
}
Comments
16 pages, 28 figures. The manuscript was accepted and is to be published