A. Petit, Share My Space; A. Rolin, Share My; L. Duthil, Share My Space; H. Tarrieu, Share My Space; R. Lucken, Share My Space; D. Giolito, Share My Space
Keywords: light curves, space object
Abstract:
Telescope networks are currently deployed to ensure a global survey of the space object population providing a large amount of astrometric data. Moreover, photometric data allow to characterize the current operational status of a satellite but this kind of measurement is often performed in a different way. Usually light curve of a space object, i.e. the measurement of the space object luminosity as a function of the time, is obtained performing a tracking of the target over several minutes during its passage in the sky. A such continuous photometric measurement allows to catch periodic variations due to the uncontrolled state of the space object attitude. However, astronomical images obtained during observational campaigns, scanning the sky, contain astrometric data but also photometric data.
Astronomical images performed during survey are obtained steering the telescope in a given direction, keeping a sidereal tracking, and acquiring consecutive images when the targeted satellite crosses the field of view. In these images, a star appears like dot although a satellites is like streak. Along the streak it is possible to extract light curve i.e. the luminosity variation of the space object during the exposure time of the image. The obtained light curve covers a time span equal to the passage duration in the field of view.
In this paper, we study light curves obtained by such passive observations of targeted space objects. Since the deployment of the first station of its telescope network in 2020, Share My Space performs automatic observations. Angular positions of streaks are catalogued but also luminosity variations. We propose to analyse them. We extract information like characteristic periods of the rotation. In the case of a time period larger than the passage duration in the field of view of the telescope, we investigate the possibility to merge measurements of several passages of the same object to reconstruct a larger time span. The results are compared with light curves obtained by tracking of the targeted object.
Date of Conference: September 27-20, 2022
Track: Non-Resolved Object Characterization