Physical parameters of selected Gaia mass asteroids

¹ Astronomical Observatory Institute, Faculty of Physics, Adam Mickiewicz University, Słoneczna 36, Poznań, Poland
e-mail: edypod@amu.edu.pl
² Max-Planck-Institut für extraterrestrische Physik (MPE), Giessenbachstrasse 1, 85748 Garching, Germany
³ Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121 Budapest, Konkoly Thege Miklós út 15-17, Hungary
⁴ Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
⁵ MTA CSFK Lendület Near-Field Cosmology Research Group, Budapest, Hungary
⁶ Astronomy Department, Eötvös Loránd University, Pázmány P. s. 1/A, H-1171 Budapest, Hungary
⁷ Observatoire des Hauts Patys, 84410 Bedoin, France
⁸ Asociación Astronómica Astro Henares, Centro de Recursos Asociativos El Cerro C/ Manuel Azaña, 28823 Coslada, Spain
⁹ B92 Observatoire de Chinon, Chinon, France
¹⁰ Oukaimeden Observatory, High Energy Physics and Astrophysics Laboratory, Cadi Ayyad University, Marrakech, Morocco
¹¹ Geneva Observatory, 1290 Sauverny, Switzerland
¹² Observatoire des Engarouines, 1606 chemin de Rigoy, 84570 Malemort-du-Comtat, France
¹³ B74, Avinguda de Catalunya 34, 25354 Santa Maria de Montmagastrell (Tàrrega), Spain
¹⁴ I39, Cruz del Sur Observatory, San Justo city, Buenos Aires, Argentina
¹⁵ Space Sciences, Technologies and Astrophysics Research Institute, Université de Liège, Allée du 6 Août 17, 4000 Liège, Belgium
¹⁶ Instituto de Astrofísica de Canarias, C/ Vía Lactea s/n, 38205 La Laguna, Tenerife, Spain
¹⁷ Gran Telescopio Canarias (GRANTECAN), Cuesta de San José s/n, 38712, Breña Baja, La Palma, Spain
¹⁸ School of Physical Sciences, The Open University, MK7 6AA, UK
¹⁹ Observatoire des Terres Blanches, 04110 Reillanne, France
²⁰ I64, SL6 1XE Maidenhead, UK
²¹ Anunaki Observatory, Calle de los Llanos, 28410 Manzanares el Real, Spain
²² The IEA, University of Reading, Philip Lyle Building, Whiteknights Campus, Reading, RG6 6BX, UK
²³ Rue des Ecoles 2, 34920 Le Cres, France
²⁴ Observatoire de Blauvac, 293 chemin de St Guillaume, 84570 Blauvac, France
²⁵ University of Ljubljana, Faculty of Mathematics and Physics Astronomical Observatory, Jadranska 19 1000 Ljubljana, Slovenia
²⁶ Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, 03080 Alicante, Spain
²⁷ Institut de Ciéncies del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franqués 1, 08028 Barcelona, Spain

Received: 25 July 2019
Accepted: 20 December 2019

Abstract

Context. Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal models, which can occasionally lead to volume uncertainties as high as 20–30%.

Aims. The aim of this paper is to determine the 3D shape models and compute the volumes for 13 main belt asteroids that were selected from those targets for which Gaia will provide the mass with an accuracy of better than 10%.

Methods. We used the genetic Shaping Asteroids with Genetic Evolution (SAGE) algorithm to fit disk-integrated, dense photometric lightcurves and obtain detailed asteroid shape models. These models were scaled by fitting them to available stellar occultation and/or thermal infrared observations.

Results. We determine the spin and shape models for 13 main belt asteroids using the SAGE algorithm. Occultation fitting enables us to confirm main shape features and the spin state, while thermophysical modeling leads to more precise diameters as well as estimates of thermal inertia values.

Conclusions. We calculated the volume of our sample of main-belt asteroids for which the Gaia satellite will provide precise mass determinations. From our volumes, it will then be possible to more accurately compute the bulk density, which is a fundamental physical property needed to understand the formation and evolution processes of small Solar System bodies.