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The Transiting Exoplanet Survey Satellite (TESS)

Presentation #406.02 in the session Transits 2.

Published onJun 20, 2022
The Transiting Exoplanet Survey Satellite (TESS)

The Transiting Exoplanet Survey Satellite (TESS) is NASA’s ongoing mission to discover planets outside the solar system, and to explore the bright and time-variable sky.

TESS uses 4 optical telescopes to repeatedly acquire images of a 24° by 96° field. The field is switched every 27 days to progressively cover the entire sky. Science operations began in July 2018. The observatory is healthy; the scientific output has grown rapidly, with a TESS publication rate of ~8 papers per week in 2021.

TESS is discovering transiting planets orbiting stars in the solar neighborhood that are bright enough to enable follow-up spectroscopic measurements of the planet’s mass, orbital characteristics, and atmospheric properties. TESS’s high photometric precision has led to the detection of >5,000 planet candidates, the largest number of detections of any ongoing survey. The candidates are being confirmed through a world-wide effort with ground-based telescopes, open to any interested astronomer.

The main goal of the TESS Prime Mission — to detect 50 planets smaller than Neptune and measure their masses — has been achieved. During the ongoing 1st Extended Mission (EM1; 2021-2022), the catalog of planet candidates has expanded to include a wider range of planet sizes and orbital periods. This includes planets in the habitable zones of low-mass stars, which offer the best prospects for atmospheric characterization with the Webb Telescope and other facilities. Thus, TESS spearheads progress toward the ultimate goal of finding life elsewhere in the Galaxy, a major priority expressed in the 2020 Astronomy and Astrophysics Decadal Survey.

The 2nd Extended Mission (EM2; 2023-2025) will bring the cumulative sky coverage to more than 95%. In addition, more than 80% of the sky will have been observed at least twice, giving access to longer-period planets. Through changes to the downlink schedule, the time sampling of TESS images will be improved from 600 to 200 sec, allowing stars to be searched for transit signals without appreciable time smearing and without needing to preselect stars of interest. EM2 will increase the number of planet candidates to >10,000, and will also feature an accelerated data delivery schedule, with calibrated image data available at the public data archive within 5 days of downlink.

TESS is an engine that is rapidly driving progress in exoplanetary science, a finderscope that identifies targets for intensive observations with Webb and other major observatories, and a source of precise time-domain optical photometry for all areas of astrophysics: a fundamental and lasting legacy for the astronomical community.


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