Journal Article

A model for saturation correction in meteor photometry

Jean-Baptiste Kikwaya, R. J. Weryk, M. Campbell-Brown and P. G. Brown

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 404, issue 1, pages 387-398
Published in print May 2010 | ISSN: 0035-8711
Published online April 2010 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2010.16294.x
A model for saturation correction in meteor photometry

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In order to correct for the effect of saturation on photometric measurements of meteors, we have developed a numerical model for saturation and apply it to data gathered using two generation III image intensified video systems on two nights (2008 October 31 and 2008 November 6). The two cameras were pointed in the same direction, and the aperture of one camera was set two stops below the aperture of the other. With these conditions, some meteors saturated one camera but not the other (group I); some saturated both cameras (group II); and some did not saturate either of them (group III). A model of meteor saturation has been developed which uses the image background value, angular meteor speed and the lateral width of the meteor image to simulate the true and saturated light curve of meteors. For group I meteors, we computed a saturation correction and applied it to the saturated light curve. We then compared the corrected saturated curve to the unsaturated curve from the other camera to validate the model. For group II meteors, a saturation correction is calculated and applied to both observed light curves, which have different degrees of saturation, and the corrected curves are compared. We collected 516 meteors, of which 30 were of group I, and seven of group II. For meteors in group I, an average residual of less than 0.4 mag was found between the observed unsaturated light curve and the model-corrected saturated light curve. For meteors in group II, the average residual between the two corrected light curves was 0.3 mag. For our data, the saturation correction goes from 0.5 to 1.9 mag for meteors in group I, and 1.2 to 2.5 mag for meteors in group II. Based on the agreement between the observed and modelled light curves (less than 0.4 mag over all meteors of all groups), we conclude that our model for saturation correction is valid. It can be used to extract the true luminosity of a saturated meteor, which is necessary to calculate photometric mass. Our model also demonstrates that fixed corrections to saturated meteor photometry, not accounting for background levels or angular velocities, do introduce significant error to meteor photometric analyses.

Keywords: meteors, meteoroids

Journal Article.  7651 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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