Candidate exoplanets as seen by TESS in a southern sky mosaic from 13 observing sectors. (NASA/MIT/TESS)
NASA’s Transiting Exoplanet Survey Satellite (TESS) has finished its one year full-sky observation of Southern sky and has found hundreds of candidate exoplanets and 29 confirmed planets. It is now maneuvering its array of wide-field telescopes and cameras to focus on the northern sky to do the same kind of exploration.
At this turning point, NASA and the Massachusetts Institute of Technology — which played a major role in designing and now operating the mission — have put together mosaic images from the first year’s observations, and they are quite something.
Constructed from 208 TESS images taken during the mission’s first year of science operations, these images are a unique space-based look at the entire Southern sky — including the Milky Way seen edgewise, the Large and Small Magellenic galaxies, and other large stars already known to have exoplanet.
“Analysis of TESS data focuses on individual stars and planets one at a time, but I wanted to step back and highlight everything at once, really emphasizing the spectacular view TESS gives us of the entire sky,” said Ethan Kruse, a NASA Postdoctoral Program Fellow who assembled the mosaic at NASA’s Goddard Space Flight Center.
The mission is designed to vastly increase the number of known exoplanets, which are now theorized to orbit all — or most — stars in the sky.
TESS searches for the nearest and brightest main sequence stars hosting transiting exoplanets, which are the most favorable targets for detailed investigations.
While previous sky surveys with ground-based telescopes have mainly detected giant exoplanets, TESS will find many small planets around the nearest stars in the sky. The mission will also provide prime targets for further characterization by the James Webb Space Telescope, as well as other large ground-based and space-based telescopes of the future.
The TESS observatory uses an array of wide-field cameras to perform a survey of 85% of the sky. With the satellite observatory it’s possible to ascertain the size and orbit of a large cohort of small planets, and then TESS and ground-based follow-up can determine mass and density.
Using the known planet size, orbit and mass, TESS and ground-based follow-up will be able to determine the planets’ compositions. This will reveal whether the planets are rocky (like Earth), gas giants (like Jupiter) or something even more unusual. Additional follow-up with ground- and space-based observatories , will also allow astronomers to study the atmospheres of many of these planets.
Here is a NASA video describing the images further, zooming in more closely on some particularly interesting features
Credits: NASA’s Goddard Space Flight Center Francis Reddy (University of Maryland College Park): Lead Science Writer Claire Andreoli (NASA/GSFC): Public Affairs Officer Scott Wiessinger (USRA): Lead Producer Scott Wiessinger (USRA): Editor Barb Mattson (University of Maryland College Park): Narrator Ethan Kruse (USRA): Visualizer
TESS is designed to survey 200,000 of the brightest stars nearest to our sun. Of the thousands of planet candidates to be identified, approximately 300 are expected to be Earth-sized and super-Earth-sized exoplanets, which are worlds no larger than twice the size of Earth.
TESS is searching for stars 30 to 100 times brighter than those the pioneering Kepler Space Telescope mission and K2 follow-up surveyed from 2009 to 2018. TESS will cover a sky area 400 times larger than that monitored by Kepler, which intentionally stared at a small section of the sky to make it’s census.
The satellite was launched on April 18, 2018 aboard a SpaceX Falcon 9 rocket. It’s primary mission is to observe for two years, but these missions often last considerably longer.
Marc Kaufman is the author of two books about space: “Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. He began writing the column in October 2015, when NASA’s NExSS initiative was in its infancy. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.