NASA's Planet-Hunting Satellite Beams Its 'First-Light' Image

NASA's planet-hunting satellite, Transiting Exoplanet Survey Satellite (TESS), beamed back its 'first light' science image. This was done as an initial round of data collection. The photo captured the cosmic space with millions of stars and various other objects from the space in the southern sky. The term 'first light' refers to the first use of a telescope (or, in general, a new instrument) to take an astronomical image after it has been constructed.

The images were clicked using all the four wide-field cameras of the spacecraft during a 30 minute period on August 7. The black lines in the image are gaps between the camera detectors. TESS took the snapshots of the Large Magellanic Cloud and bright star, R Doradus, with just a single detector of one of its cameras.

"In a sea of stars brimming with new worlds, TESS is casting a wide net and will haul in a bounty of promising planets for further study. This first light science image shows the capabilities of TESS' cameras, and shows that the mission will realize its incredible potential in our search for another Earth," said Paul Hertz, astrophysics division director at NASA Headquarters in Washington.

The photo captures constellations from Capricornus to Pictor, and both the Large and the Small Magellanic Clouds, the nearest galaxies to our Milky Way. Above the Small Magellanic Cloud is a 'globular cluster' - a spherical collection of hundreds of thousands of stars named NGC 104, better known as 47 Tucanae because of its location in the southern constellation Toucana, the Toucan. The brightest stars, R Doradus and Beta Gruis, saturate an entire column of pixels on the detectors of TESS' second and fourth cameras, creating long streaks of light.

"This swath of the sky's southern hemisphere includes more than a dozen stars we know have transiting planets based on previous studies from ground observatories," said George Ricker, TESS principal investigator at the Massachusetts Institute of Technology's (MIT) in the US.

TESS' cameras monitor large swaths of the sky to look for transits. Transits occur when a planet passes in front of its star as viewed from the satellite's perspective, causing a regular dip in the star's brightness. TESS continues the legacy of NASA's Kepler spacecraft, which also uses transits to find exoplanets.

TESS's target stars are 30 to 300 light-years away and about 30 to 100 times brighter than Kepler's targets, which are 300 to 3,000 light-years away. The brightness of TESS' targets makes them ideal candidates for the follow-up study with spectroscopy, the study of how matter and light interact.

What's next for TESS?

TESS will spend two years monitoring 26 such sectors for 27 days each, covering 85 per cent of the sky. During its first year of operations, the satellite will study the 13 sectors making up the southern sky. Then, it will turn to the 13 sectors of the northern sky to carry out a second year-long survey.

(With PTI Inputs)