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Database – DescriptionLight curve inversionWe present asteroid models that were derived using the lightcurve inversion method (Kaasalainen et al. 2001; Kaasalainen & Torppa 2001), combined with other inversion techniques in some cases. For each asteroid, we list the ecliptic coordinates of its spin axis, its sidereal rotation period, the reference to the original publication, and other parameters and comments related to the model. Please note that results presented here may differ from those published in the original papers. The main reason for this is a limited dataset used in the original publication or/and a narrow range of periods scanned during the inversion. File formatsShape models (SHP), spins (SPIN)The shape models are represented as polyhedrons with triangular surface facets. The format of shape files (SHP) is as follows: The first line gives the number of vertices and facets, then follow the vertex x, y, z coordinates (defining radius vectors r_{ast}), then for each facet the order numbers of facet vertices (anticlockwise seen from outside the body). The orientation of a model at epoch t is given by a transformation between vectors r_{ast} in the asteroid corotating coordinate frame and vectors r_{ecl} in the ecliptic coordinate frame. The transformation is given by the equation where R_{i}(θ) is the rotation matrix corresponding to the rotation of a vector through the angle θ along the iaxis in the anticlockwise direction λ and β are ecliptic longitude and latitude of the spin axis respectively, P is the rotation period, φ_{0} is the initial rotation angle, and t_{0} is the initial epoch. In some cases, the nonzero linear change of the rotation rate υ caused by the YORP effect must be taken into account. The corresponding rotation matrix is then Values λ, β (degrees), P (hours), t_{0} (JD epoch), and φ_{0} (degrees) are given in spin (SPIN) files. If there is the third line in a spin file, it gives the scattering parameters described in the corresponding comment column. Lightcurves (LC)The models are based on lightcurve data that are stored in lightcurve files (LC). The first line gives the total number of lightcurves, then the individual lightcurves follow in blocks. Each lightcurve starts with the number of points and 0/1 code for a relative (0) or calibrated (1) lightcurve. Then there are lines with the lighttime corrected JD epoch, the brightness in intensity units (reduced to unit distances from the Earth and the Sun when calibrated), the ecliptic asteroidcentric cartesian coordinates x, y, z of the Sun and of the Earth in AU. Follow the references for a detailed description of the lightcurve data (observers, telescopes, filters,...). Lightcurve References (LCref)The LCref files list references for lightcurves (served in LC files). The references are in the same order as the lightcurves: For example the third line/reference in the LCref corresponds to the third lightcurve in the LC file. The columns in the LCref files are: the serial number of the reference/lightcuve; the mean year, month and day of observation; the reference shortcut. The references are fully expanded in references.txt file. Shape vizualization (PNG, 3D)Each shape model is shown from three directions in the corresponding PNG file. There are two views from asteroid's equator and one from its pole. The three views correspond to the views from the positive x, y, z axes, respectively. The lightscattering model used for rendering has no physical meaning and was chosen just for visualization purposes. For each model, there is also an interactive 3D animation that works with Acrobat Reader 8 or higher. Spin parameters according to the IAU recommendation (IAUspin)The IAUspin file gives the parameters of the rotation state according to the recommendations of the IAU (Seidelmann et al. 2007, Celestial Mech. Dyn. Astr. 98, 155): α_{0}, δ_{0}, dW / dt (the first line), and t_{0}, W_{0} (the second line). Here α_{0} and δ_{0} are equatorial coordinates of the pole (degrees), dW / dt is the rotation rate (deg/day), and t_{0} is the initial epoch for which the position of the prime meridian is W_{0} (degrees). The position of the prime meridian at the time t is W = W_{0} + dW / dt (t  t_{0}). The prime meridian is defined by the positive x axis. Occultations (occ)Some models in the database were scaled to fit the occultation data. For these asteroids, the skyplane projection of the model was computed for the time of occultation and plotted together with the occultation chords. The meaning of different types of lines and curves is explained in occ_explanation.pdf (PDF 9.8 KiB). For more details see Ďurech et al. (2011), Icarus, in press, preprint (PDF 468 KiB). Wavefront .obj file (OBJ)The shape model is also provided in the OBJ format, that is recognized by most 3D graphics applications. More about this format can be found at http://en.wikipedia.org/wiki/Wavefront_.obj_file. Models visualisation (sky projection)Besides the PNG and 3D files, we also provide an online service for models visualisation. The service allows you to generate a model's sky projection for an arbitrary time (Julian Date). The service is available for all models, which have a corresponding shape file (SHP) in the database. The link to the service is accessible from the detailed view of an asteroid, in the model row Services, and redirects you to a prefilled form, where you can adjust the Julian Date. Note that the prefilled Julian Date corresponds to today's noon. After clicking the Show projection button, a new tab (or window) with the projection will open. The projection takes usually several seconds, so, please, don't reload the page if the results are not displayed immediately. The projection shows two pictures. First represents a given model illuminated by the Sun, second represents the model under artificial illumination to show its outline in the sky. Both pictures show the model as viewed from Earth at a given Julian Date; the north is up and west is right. The projection also takes into account the lighttime effect: The model's orientation is computed for the retarded time t_{ret} = t − Δ/c, where t is the observation time, Δ is the distance between the asteroid and Earth and c is the speed of light. The database structureThe data are presented in the table form, ordered by the selected asteroid label (number, name, designation). Below the asteroid label row there are generally several rows containing corresponding models which represent solutions to the lightcurve inversion problem. The meaning of the columns (database fields) is as follows:
Note 1: Default values are: Lightscattering model = 'LSL'; p_{1} = 0.1; p_{2}, p_{3}, p_{4}, p_{5} not defined. References
