Fifth European Conference on Space Debris
30 March - 2 April 2009
MULTYCOLOR PHOTOMETRY AND SPECTROPHOTOMETRY SPACE DEBRIS OBJECTS
P. Papushev ; M. Mishina, T. Tsouker
Institute of solar-terrestrial physic, Siberian branch Russian academy of science
Irkutsk, p.b. 291 firstname.lastname@example.org
Paper Presented at the 5th European Space Debris Conference,
Darmstadt Germany, March 30 - April 2 2009
Specific programs for metric and spectrophotometric observations of space debris with the telescopes at the Sayan observatory were conducted. Several features of the AZT 14 and AZT 33 telescopes and its control system are very sutable for small-sized objects oservation. Ephemeridal support of the observations includes the dynamic catalog of the debris objects KIAM, (V.Agapov et al. 2007) which is represented by database table, containing orbital characteristics. The software package SATRADANA (V.Yurasov et al. 1995) had been imported to the telescope control system. The individuale programs of the package may be used for orbit improvement and prediction. Calculation of ephemerides is performed in the given time interval (dark part of the day) with the time spacing 1 min., which is enough for the objects that are moving with the speeds about several ''/s.
The equipment and methods for multicolor photometry of a small sized movie debris were developed. The equipment and software of the telescope control system allow, by the use a predicted orbit to make precision tracking of object and it is reliable to detect mobile objects of 22 magnitude.
The optical properties in visible wavelengths of small sized debris objects at GTO and GEO had been studied. The time serias of the frames at BVR filters were obtained. A time resolution in a serias had been definded by the exposure time in the given filter. An ordinary situation it was equel from 1 to 3 seconds for R and V filters and 5-10 seconds for B filter as a compromise between a signal to noise ratio and a periods of a brightening variaton was marked. The procedure was repiated at different phase angles during to objects visibility. The observable debris objects have various mean brightness in the range from 14 up to 20.5 magnitude and various colors (B-V) and a dynamic of the brightness variation. A photometrical accuracy can be estimated from a some qualitatively reasons and was no more than 0.05 magnitudes. The photometrical properties of the debris objects being observed tube are summarized in a figures on right side of the poster.
Low-resolution spectrometer at advanced telescope AZT 33 was applied to spectrophotometrical study of an object irradiation . At the figures below one can see example of spectra of three different GEO objects labeled on FOV frame. With a custom CCD camera spectra and slit imagers can be obtained simultaneously, The spectra presented below were obtained with expose time 2.5 s . The hardware for spectral investigation one can see at bottom left picture.
A Time and Phase dependences of magnitude , light curves and color indexes distribution for Transtage IV, Ekran 2 and for high mass – area objects.
From the results of multicolor photometrical observations and a light curves analyses of the non active geostationary spacecraft and faint debris objects it is possible to deduce any conclusions about an objects suspect of destruction on the base of orbits analyses. The fragments in close neighborhood to an orbit of the Ekran 2, Transtage IV and other object were investigated. Attempt of an identification of the 7 debris objects with the Ekran 2 design by using B-V color index were made. Amongst the families objects there are only bjects 11581 that have the appearance of solar panels. Its light curver have been demonstated two bell-like details, approximately identical duration, but distinguished on amplitude on 1.5-2 magnitudes. At the specific moments at the top of a smaller magnitudes detail a short mirror flashe with an amplitudes of 8 magnitudes and strong bluring effect have been observed. This kind of the light curver behaviour are typical to solar panels one. Notably that no mirror flash and bluring effects being detected for Ekran 2 parental body. The other objects are allocated along a "tube" of trajectories near Ekran 2 , Transtage et al parental body does not demonstrated any sign of mirrors effect. There are much reddening objects in comparison with average color of space objects with entirely diffuse indicatrix.
Observations of the faint space debris objects in the geostationary rings have been performed since 2007 year . The experimental equipment at Sayan mounting observatory of Institute of Solar Terrestrial physics provides the opportunity of a detection of moving objects up to 22 (R) magnitudes in the tracking mode. For measuring of a spectral brightness the CCD photometer has been used. Commonly used UBVRI filters are located in gear -driven filter wheel in the focal reducer optical scheme. In the multicolor photometrical mode, which is at first sight more adequately for faint objects, the measurements are executed consequently with expose time choosing by observer. For simultaneous measurements in different spectral bands a low dispersion slit spectrometers with custom CCD device was commissioned.
Размещено 20 мая 2009
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