Time-series asteroid photometry with TESS

The Transiting Exoplanet Survey Satellite (TESS) is observing thousands of solar system asteroids during its ongoing all-sky photometric survey. These asteroids move through the TESS Full Frame Images, providing photometry with a cadence of ≤ 30 minutes and a typical observing baseline of ~ 27 days. This offers the unique opportunity to homogeneously study a large sample of asteroids and improve our knowledge of their rotation period distribution and binary fraction.To facilitate this endeavor, we have developed tess-asteroids – a flexible, open-source Python package that creates image cutouts and light curves for asteroids observed by TESS. From user input, either the name of a known asteroid or the ephemeris of a new target, our code creates an image cutout that tracks the object over time, performs background correction and extracts a light curve using aperture photometry. It saves these results as Target Pixel Files (TPFs) and Light Curve Files (LCFs), using the same format as the TESS data products.Using tess-asteroids, we have created TPFs and LCFs for a sample of bright (V < 19) asteroids observed during the TESS primary mission. We will present our Python package, an assessment of its computing performance, a comparison of our results to existing studies and provide a first look at our asteroid rotation period distribution.Figure 1: Image cutout, light curve and rotation period analysis for asteroid 1980 VR1. Left: a single frame from the TPF created by tess-asteroids. The target aperture is included, as well as a marker indicating the flux-weighted centroid of the asteroid. Center: light curve created by tess-asteroids. Right: the periodogram of the light curve shows a strong peak at the expected rotation period (10.22 hrs).