Photometric survey, modelling, and scaling of long-period and low-amplitude asteroids

Abstract

The available set of spin and shape modelled asteroids is strongly biased against slowly rotating targets and those with low lightcurve amplitudes. As a consequence of these selection effects, the current picture of asteroid spin axis distribution, rotation rates, or radiometric properties, might be affected too. To counteract these selection effects, we are running a photometric campaign of a large sample of main belt asteroids omitted in most previous studies. We determined synodic rotation periods and verified previous determinations. When a dataset for a given target was sufficiently large and varied, we performed spin and shape modelling with two different methods. We used the convex inversion method and the non-convex SAGE algorithm, applied on the same datasets of dense lightcurves. Unlike convex inversion, the SAGE method allows for the existence of valleys and indentations on the shapes based only on lightcurves. We obtained detailed spin and shape models for the first five targets of our sample: (159) Aemilia, (227) Philosophia, (329) Svea, (478) Tergeste, and (487) Venetia. When compared to stellar occultation chords, our models obtained an absolute size scale and major topographic features of the shape models were also confirmed. When applied to thermophysical modelling, they provided a very good fit to the infrared data and allowed their size, albedo, and thermal inertia to be determined. Convex and non-convex shape models provide comparable fits to lightcurves. However, some non-convex models fit notably better to stellar occultation chords and to infrared data in sophisticated thermophysical modelling (TPM). In some cases TPM showed strong preference for one of the spin and shape solutions. Also, we confirmed that slowly rotating asteroids tend to have higher-than-average values of thermal inertia.

arXiv commentAccepted in astronomy astrophys. 39 pages, 49 figures

References in corpus (20)

• Density of asteroids
• Main Belt Asteroids with WISE/NEOWISE I: Preliminary Albedos and Diameters
• NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
• Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes
• Volumes and bulk densities of forty asteroids from ADAM shape modeling
• Asteroids' physical models from combined dense and sparse photometry and scaling of the YORP effect by the observed obliquity distribution
• New and updated convex shape models of asteroids based on optical data from a large collaboration network
• ADAM: a general method for using various data types in asteroid reconstruction
• Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia
• Asteroid models from the Lowell Photometric Database
• (25143) Itokawa: The Power of Radiometric Techniques for the Interpretation of Remote Thermal Observations in the Light of the Hayabusa Rendezvous Results
• 3D shape of asteroid (6)~Hebe from VLT/SPHERE imaging: Implications for the origin of ordinary H chondrites
• The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids
• Herschel celestial calibration sources: Four large main-belt asteroids as prime flux calibrators for the far-IR/sub-mm range
• Thermal Tomography of Asteroid Surface Structure
• Testing the inversion of asteroids' Gaia photometry combined with ground-based observations
• Against the biases in spins and shapes of asteroids
• Uninterrupted optical light curves of main-belt asteroids from the K2 Mission
• Distribution of spin-axes longitudes and shape elongations of main-belt asteroids
• A new non-convex model of the binary asteroid 90 Antiope obtained with the SAGE modelling technique

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• SsODNet: The Solar system Open Database Network
• Asteroid models reconstructed from ATLAS photometry
• Asteroid models reconstructed from the Lowell Photometric Database and WISE data
• The homogeneous internal structure of CM-like asteroid (41) Daphne
• Thermal properties of slowly rotating asteroids: Results from a targeted survey
• Combined spin orientation and phase function of asteroids
• Main-belt asteroids in the K2 Uranus field
• Thermal properties of large main-belt asteroids observed by Herschel PACS
• TESS in the Solar System
• Small Bodies: Near and Far Database for thermal infrared observations of small bodies in the Solar System
• Thermophysical Investigation of Asteroid Surfaces II: Factors Influencing Grain Size
• $V$-band photometry of asteroids from ASAS-SN: Finding asteroids with slow spin
• Reconstruction of asteroid spin states from Gaia DR2 photometry
• Properties of slowly rotating asteroids from the Convex Inversion Thermophysical Model
• Volume uncertainty assessment method of asteroid models from disk-integrated visual photometry
• Asteroid phase curves using sparse Gaia DR2 data and differential dense light curves
• Scaling slowly rotating asteroids by stellar occultations
• Light curves of transneptunian objects from the K2 mission of the Kepler Space Telescope
• Physical parameters of selected Gaia mass asteroids
• Asteroid sizes determined with thermophysical model and stellar occultations