Apophis as observed by TESS

NASA’s TESS mission was launched in 2018 with a goal to discover exoplanets around nearby, bright stars. TESS stares at a 2,300 deg² region of the sky continuously for ~27 days and records the brightness of the entire focal plane every thirty minutes. After ~ 27 days, the telescope moves onto another region (sector) and repeats the survey. Not only is this observing strategy excellent for discovering exoplanets, but it can also provide a unique, uninterrupted view of a variety of objects, including solar system moving bodies. However, near earth asteroids can be particularly challenging to extract from TESS data since they often move across several pixels in each thirty minute exposure. We utilized dynamic PSF photometry to successfully extract a high quality light curve of Apophis from TESS’s sector 35. The data spans from February 19 to March 6, 2021 and has nearly uninterrupted coverage for the last week. This light curve provides a unique uninterrupted view of a tumbling asteroid as well as a highly detailed baseline of Apophis’ rotation state prior to it’s 2029 close approach.