The TESS mission has several data products ranging from the TESS input catalog to a catalog of planet candidates. Here we give an overview of what information is in each data product, how it is produced and how the data is formatted.
TESS obtains time-series photometry at two different cadences with a baseline ranging from 3 weeks out to a year. An overview of the primary science products are shown above. The entire set of CCDs for each TESS sector are downloaded every 30-minutes, these are known as the Full Frame Images (FFIs). Selected sections of sky are also downloaded at a 2-minute cadence. The the pixels at each time stamp are stored as arrays in target-pixel files. Aperture photometry is performed on each image creating an array of fluxes; these are stored in a light curve file. Those flux time series are then searched for repeating signals consistent with a transiting planet, known as a Threshold Crossing Event (TCE). The TCEs, as well as signals found by searching light curves created from the FFIs, are turned into TESS Objects of Interest (TOI) when the data is sufficiently consistent with a transit. The TOI list contains both planet candidates and false positives. False positives are those with evidence of being an eclipsing binary. Once follow-up measurements reveal the planet's mass the planet is considered confirmed.
Description of Primary TESS Data Products.
- TESS Input Catalog (TIC): Catalog of stars used by the TESS mission to select targets to download at short cadence. The TIC is available through the MAST portal and via the API.
- Full Frame Images (FFI):
- Target Pixel Files (.tp.fits): These files contain a time series of the raw and calibrated pixels downloaded at the 2-minute cadence.
- Light Curve Files (.lc.fits): These files contain the simple aperture photometry flux time series derived from the calibrated short-cadence pixels. It also contains a co-trended light curve that attempts to preserve astrophysics.