Asteroid sizes determined with thermophysical model and stellar occultations
Abstract
Context. The sizes of many asteroids, especially slowly rotating, low-amplitude targets, remain poorly constrained due to selection effects. These biases limit the availability of high-quality data, leaving size estimates reliant on spherical shape assumptions. Such approximations introduce significant uncertainties propagating, e.g. into density determinations or thermophysical and compositional studies, affecting our understanding of asteroid properties. Aims. This work targets poorly studied main-belt asteroids, most of which lacked shape models. Using only high-quality dense light curves, thermal IR observations (incl. WISE), and stellar occultations, we aimed to produce reliable shape models and scale them via two independent techniques, allowing size comparison. We conducted two campaigns to obtain dense photometric light curves and to acquire multi-chord stellar occultations. Methods. Shape and spin models were reconstructed using lightcurve inversion. Sizes were determined by (1) thermophysical modeling with the Convex Inversion Thermophysical Model (CITPM), optimizing spin and shape models to visible lightcurve and IR data, and (2) scaling shape models with stellar occultations. Results. We obtained precise sizes and shape models for 15 asteroids. CITPM- and occultation-derived sizes agree within 5% in most cases, demonstrating the modeling's reliability. Larger discrepancies usually stem from incomplete occultation chord coverage. The study also gives insights into surface properties incl. albedo, roughness and thermal inertia. Conclusions. Using high-quality data and an advanced TPM integrating thermal and visible data with shape adjustment enabled precise size estimates comparable to those from multi-chord stellar occultations. We resolved major inconsistencies in previous size estimates, providing solid input for future studies on asteroid densities and surfaces.
Keywords
Cite
@article{arxiv.2505.09437,
title = {Asteroid sizes determined with thermophysical model and stellar occultations},
author = {A. Choukroun and A. Marciniak and J. Ďurech and J. Perła and W. Ogłoza and R. Szakats and L. Molnar and A. Pal and F. Monteiro and I. Mieczkowska and W. Beisker and D. Agnetti and C. Anderson and S. Andersson and D. Antuszewicz and P. Arcoverde and R. -L. Aubry and P. Bacci and R. Bacci and P. Baruffetti and L. Benedyktowicz and M. Bertini and D. Blazewicz and R. Boninsegna and Zs. Bora and M. Borkowski and E. Bredner and J. Broughton and M. Butkiewicz - Bąk and N. Carlson and G. Casalnuovo and F. Casarramona and Y. -J. Choi and S. Cikota and M. Collins and B. Cseh and G. Csörnyei and H. De Groot and P. Delincak and P. Denyer and R. Dequinze and M. Dogramatzidis and M. Drozdz and R. Duffard and D. Eisfeldt and M. Eleftheriou and C. Ellington and S. Fauvaud and M. Fauvaud and M. Ferrais and M. Filipek and P. Fini and M. Frits and B. Gährken and G. Galli and D. Gault and S. Geier and B. Gimple and J. Golonka and L. Grazzini and J. Grice and K. Guhl and W. Hanna and M. Harman and W. Hasubick and T. Haymes and D. Herald and D. Higgins and R. Hirsch and J. Horbowicz and A. Horti - David and B. Ignacz and E. Jehin and A. Jones and R. Jones and D. Dunham and Cs. Kalup and K. Kaminski and M. K. Kaminska and P. Kankiewicz and M. Kaplan and A. Karagiannidis and B. Kattentidt and S. Kidd and B. Kirpluk and D. -H. Kim and M. -J. Kim and I. Konstanciak and G. Krannich and M. Kretlow and J. Kubanek and V. Kudak and P. Kulczak and M. Lecossois and R. Leiva and M. Libert and J. Licandro and P. Lindner and R. Liu and Y. Liu and G. Lyzenga and M. Maestripieri and C. Malagon and P. Maley and A. Manna and S. Messner and O. Michniewicz and M. A. Miftah and M. Mizutani and N. Morales and M. Murawiecka and J. Nadolny and T. Nemoto and J. Newman and V. Nikitin and P. Nosal and P. Nosworthy and M. O'Connell and J. Oey and A. M. Ortiz-Ochoa and A. Ossola and D. Oszkiewicz and E. Pakstiene and M. Pawlowski and V. Perig and E. Petrescu and F. Pilcher and E. Podlewska-Gaca and M. Polacek and J. Polak and T. Polakis and M. Polinska and A. Popowicz and V. Reddy and J. -J. Rives and M. Rottenborn and N. Ruocco and A. Rutkowski and K. Saci and T. Santana-Ros and K. Sarneczky and O. Schreurs and V. Sempronio and B. Skiff and J. Skrzypek and D. Smith and K. Sobkowiak and E. Sonbas and S. Sposetti and C. Stewart and W. Stewart and T. Swift and M. Szkudlarek and K. Szyszka and N. Takacs and L. Tychoniec and M. Uno and S. Urakawa and K. Vida and C. Weber and N. Wünsche and H. Yamamura and H. Yoshihara and M. Zawilski and P. Zeleny and S. Zola and M. Zejmo and K. Zukowski},
journal= {arXiv preprint arXiv:2505.09437},
year = {2025}
}