A series of 208 images taken over the past year by the agency’s Anti-Japanese Exoplanet Survey Satellite (TESS) reveal a dazzling sea of stars and 74 exoplanets in the northern sky, NASA said Monday. Currently, TESS has captured about 75% of the sky in two years. The “planet hunter” ended its second year of scientific operations in July.
Astronomers are looking at another 1,200 exoplanet candidates to see if there is a new world there. NASA says more than half of these candidate planets are in the northern sky.
TESS precisely locates planets by monitoring large areas of the sky at the same time as several stars and keeping an eye on any small changes in brightness. When a planet moves in front of its host star, it blocks part of the star’s light, causing the star to temporarily darken. This happens every time a planet orbits its star, known as the “Ling Sun.”
“This technology has proven to be the most successful planet-finding strategy to date, accounting for about three-quarters of the nearly 4,300 exoplanets known to date,” NASA said. “The data collected can also look at other phenomena in unprecedented detail, such as star changes and supernova explosions.”
In its first year of operation, TESS captured panoramic views of the southern sky. Mosaics in the northern sky are not as vast because “for about half of the northern sectors, the team decided to place the camera’s angle further north to minimize the impact of scattered light from Earth and the moon,” NASA explained. “This has led to a prominent coverage gap.”
This panorama represents only a small portion of the data collected by TESS. The mission divided each astro hemisphere into 13 sections. TESS then uses four cameras to shoot each section for about a month. These cameras contain a total of 16 sensors called charge coupling devices.
TESS will now return to the southern sky for imaging for a year. It will revisit previously discovered planets, locate new ones, and fill any coverage gaps in the first survey. Improved data collection and processing means that TESS will be able to send back full sector images every 10 minutes. In addition to continuing to measure the brightness of tens of thousands of stars every two minutes, the satellite will be able to measure the brightness of thousands of stars every 20 seconds.
“These changes are expected to make TESS’s extended mission more productive,” Padi Boyd, a mission project scientist at NASA’s Goddard Space Flight Center, said in a press release. “High-precision measurements of star brightness at these frequencies make TESS an extraordinary new resource for studying flares and pulsing stars and other transient phenomena, as well as the science of exploring exoplanets.”