This artist's concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star. Credit: NASA-JPL/Caltech
The raw cadence data for the K2 observations of the TRAPPIST-1 system are now available.
The calibrated Light Curves and Target Pixel Files should arrive some time in June, and
will have K2 IDs 200164267 and 246199087, both observed in short cadence. The K2 ID 200164267
is an 11x11 pixel custom mask, while K2 ID 246199087 is a smaller, standard-sized mask, for which
the project will produce calibrated products. The smaller 246199087 mask is a subset of the 200164267
11x11 mask. As such, users who want to create their own light curves for TRAPPIST-1 using custom
apertures are advised to download the data for the larger 200164267 mask.
Users may use the Python-based Kadenza
software tool to extract the raw data. The README file at github is also a good source for
understanding the content of these files. The Format Information for Cadence Pixel Files document describes both the raw
cadence data and the associated pixel mapping reference files.
An "unofficial" set of TRAPPIST-1 Target Pixel Files (TPF) have been provided by Geert Barensten, which will compress all the raw cadence data into one file.
The TPF is a time series of images in a binary FITS table, where each image
(roughly 11x11 pixels) represents a single cadence.
Download the unofficial, "pseudo-TPF" file, created by Geert Barensten:
Important warnings and caveats can be found at this K2 Mission Office blog post.
Simulated image of TRAPPIST-1's location on the detector, from the "Create Optimal Aperture" component of the Photometric Analysis module. The 11x11-pixel aperture of K2 ID 200164267 is represented by the yellow dots. The output module for TRAPPIST-1 is 19.4, it's channel is 68, and it's located approximately at pixel row 27, column 992.
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