Physical models of asteroids from sparse photometric data

Ďurech, Josef; Scheirich, P.; Kaasalainen, M.; Grav, T.; Jedicke, Robert; Denneau, L.

doi:10.1017/s1743921307003225

Cited by 13 publications

(7 citation statements)

References 13 publications

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“…We note that the general feasibility of the inversion of sets of photometric data obtained from sparse observations of convexshape asteroids, in cases in which the data cover a sufficiently wide variety of observing circumstances, was first demonstrated in the pioneering work by Kaasalainen (2004), while later results were published by Durech et al (2007). The possibility of inverting a set of photometric measurements including both sparsely and frequently sampled (light-curve) data, was shown by .…”

Section: Asteroid Photometry: a Few Basic Conceptsmentioning

confidence: 86%

Genetic inversion of sparse disk-integrated photometric data of asteroids: application to Hipparcos data

Cellino

Hestroffer²,

Tanga³

et al. 2009

A&A

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Context. The development of techniques for the inversion of sparse disk-integrated photometric data of asteroids is a very urgent task, due to the imminent commencements of large sky surveys from both space (Gaia) and the ground (Pan-STARRS). Aims. We developed a numerical algorithm for the inversion of sparse photometric data of asteroids. An application to real data collected in past by the Hipparcos satellite provided very encouraging results. Methods. The inversion method is based on the application of a "genetic" algorithm approach. The objects are assumed to have triaxial ellipsoid shape. However, it is shown by means of simulations and applications to real data that this simplistic choice does not cause any significant problems. The algorithm solves for a number of unknown parameters, including the spin period, the coordinates of the spin axis, the axial ratios of the ellipsoid, an initial rotational phase corresponding to the first observation of a given dataset, and the slope of a linear variation in the magnitude as a function of solar phase. Additional parameters, describing some possible albedo variegation of the surface, can also be introduced. Results. The application of the inversion technique to both simulations and a dataset of sparse photometric data obtained some years ago by the Hipparcos satellite shows that the performance of the algorithm is strongly encouraging, and the correct solution for the rotational parameters is obtained in the majority of cases when a reasonable number of observations are available.

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Section: Asteroid Photometry: a Few Basic Conceptsmentioning

confidence: 86%

Genetic inversion of sparse disk-integrated photometric data of asteroids: application to Hipparcos data

Cellino

Hestroffer²,

Tanga³

et al. 2009

A&A

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show abstract

“…As has been suggested by many simulations (Kaasalainen 2004;Durech et al 2005Durech et al , 2007, this so-called "sparse photometry" can be used the same way as standard dense lightcurves to derive basic physical parameters of observed asteroids: the global shape, the spin axis direction, and the rotation period.…”

Section: Sparse Lightcurve Inversionmentioning

confidence: 99%

LSST Science Book, Version 2.0

Abell¹,

Burke²,

Hamuy³

et al. 2009

552

653

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Prepared by the LSST Science Collaborations, with contributions from the LSST Project. PrefaceMajor advances in our understanding of the Universe over the history of astronomy have often arisen from dramatic improvements in our ability to observe the sky to greater depth, in previously unexplored wavebands, with higher precision, or with improved spatial, spectral, or temporal resolution. Aided by rapid progress in information technology, current sky surveys are again changing the way we view and study the Universe, and the next-generation instruments, and the surveys that will be made with them, will maintain this revolutionary progress. Substantial progress in the important scientific problems of the next decade (determining the nature of dark energy and dark matter, studying the evolution of galaxies and the structure of our own Milky Way, opening up the time domain to discover faint variable objects, and mapping both the inner and outer Solar System) all require wide-field repeated deep imaging of the sky in optical bands.The wide-fast-deep science requirement leads to a single wide-field telescope and camera which can repeatedly survey the sky with deep short exposures. The Large Synoptic Survey Telescope (LSST), a dedicated telecope with an effective aperture of 6.7 meters and a field of view of 9.6 deg 2 , will make major contributions to all these scientific areas and more. It will carry out a survey of 20,000 deg 2 of the sky in six broad photometric bands, imaging each region of sky roughly 2000 times (1000 pairs of back-to-back 15-sec exposures) over a ten-year survey lifetime.The LSST project will deliver fully calibrated survey data to the United States scientific community and the public with no proprietary period. Near real-time alerts for transients will also be provided worldwide. A goal is worldwide participation in all data products. The survey will enable comprehensive exploration of the Solar System beyond the Kuiper Belt, new understanding of the structure of our Galaxy and that of the Local Group, and vast opportunities in cosmology and galaxy evolution using data for billions of distant galaxies. Since many of these science programs will involve the use of the world's largest non-proprietary database, a key goal is maximizing the usability of the data. Experience with previous surveys is that often their most exciting scientific results were unanticipated at the time that the survey was designed; we fully expect this to be the case for the LSST as well.The purpose of this Science Book is to examine and document in detail science goals, opportunities, and capabilities that will be provided by the LSST. The book addresses key questions that will be confronted by the LSST survey, and it poses new questions to be addressed by future study. It contains previously available material (including a number of White Papers submitted to the ASTRO2010 Decadal Survey) as well as new results from a year-long campaign of study and evaluation. This book does not attempt to be complete; there are many ...

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“…This is very useful in applications such as i) searching for the correct period in sparse photometric datasets from sky surveys when no period is evident a priori and a wide period range must be combed through (Kaasalainen 2004;Ďurech et al 2006, 2007; ii) Monte-Carlo sampling to estimate the goodnessof-fit levels of the rotation parameters and thus their likelihood distributions; or iii) searching for and then fixing the pole and period prior to producing a high-resolution version of the shape as is usually done in the convex inversion procedure (Kaasalainen et al 2001). Upon computing sample lightcurve inversion cases for targets previously analysed with tessellation, and using a reduced number of Lebedev evaluation points in accordance with Fig.…”

Section: Efficiency In Lightcurve Simulation and Inversionmentioning

confidence: 99%

Optimal computation of brightness integrals parametrized on the unit sphere

Kaasalainen¹,

Lu²,

Vänttinen³

2012

A&A

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We compare various approaches to find the most efficient method for the practical computation of the lightcurves (integrated brightnesses) of irregularly shaped bodies such as asteroids at arbitrary viewing and illumination geometries. For convex models, this reduces to the problem of the numerical computation of an integral over a simply defined part of the unit sphere. We introduce a fast method, based on Lebedev quadratures, which is optimal for both lightcurve simulation and inversion in the sense that it is the simplest and fastest widely applicable procedure for accuracy levels corresponding to typical data noise. The method requires no tessellation of the surface into a polyhedral approximation. At the accuracy level of 0.01 mag, it is up to an order of magnitude faster than polyhedral sums that are usually applied to this problem, and even faster at higher accuracies. This approach can also be used in other similar cases that can be modelled on the unit sphere. The method is easily implemented in lightcurve inversion by a simple alteration of the standard algorithm/software.

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Physical models of asteroids from sparse photometric data

Cited by 13 publications

References 13 publications

Genetic inversion of sparse disk-integrated photometric data of asteroids: application to Hipparcos data

Genetic inversion of sparse disk-integrated photometric data of asteroids: application to Hipparcos data

LSST Science Book, Version 2.0

Optimal computation of brightness integrals parametrized on the unit sphere

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