TESS, the new planet-hunter of NASA, sends its first image to the Earth.

The Explorer Program of NASA wanted to extend the good work of Kepler Mission and for this reason, they designed the Transiting Exoplanet Survey Satellite (TESS). It is expected to trace around 20,000 exoplanets in comparison to 3,800 exoplanets that were found before its launch. The launch was executed earlier this year on the 18^th of April as a Falcon 9 rocket took this amazing satellite into space. The key to its success lies in its design. It uses the transit method which allows it to cover 400 times more area than the Kepler Space Telescope.

Although it is designated the task of finding the far-off exoplanets, the primary mission of TESS is to locate and explore the brightest stars near Earth for transiting exoplanets. A recent announcement of NASA indicated that this new planet hunter has started its operation. They released an image taken by the TESS which showed sparkling stars and two nearby galaxies. Despite the fact that none of the exoplanets were visible in this image, scientists are confident that the data provided by this amazing satellite will carry immense importance for discovering new exoplanets. Paul Hertz, the Director of the Astrophysics Division at NASA Headquarters, talked about the potential of the TESS and said,

“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.”

The first image of the TESS was captured by using all the four cameras of the satellite. The field of view included both the Large and Small Magellanic Clouds and as much as 12 constellations ranging from Capricornus and Pictor. NGC 104 (47 Tucanae), a globular cluster of old stars, is also visible in this image above the Small Magellanic Cloud. R Doradus and Beta Gruis are the brightest stars among all the stars captured in this image. They are so bright that an entire column of pixels was saturated on the detectors of the second and fourth cameras of the TESS. This created long spikes of light which are clearly visible in the released image. George Ricker, the Principal Investigator of the TESS who is an Astrophysicist at MIT, referred to this achievement by saying,

“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.”

The working principle of the TESS is similar to its predecessor, the Kepler Space Telescope. It also looks for ‘Transits’, which occur when a planet passes in front of its host star from the perspective of the satellite. This change in brightness of the star helps in exploring new exoplanets. TESS will monitor a total of 26 such sectors in the first two years of its operation. It will spend 27 days in each of these sectors. According to NASA, it will study 13 sectors across the southern sky in the first year while 13 sectors of the northern sky will be observed in the second year. The officials at NASA claims that as much as 85% of the sky will be covered in this mission. TESS orbits the Earth every 13.7 days and sends new images back to the Earth through the Deep Space Network of NASA after completing each rotation.

The target stars that TESS would need to study are 30 to 300 light-years away from our planet. For this reason, the exoplanets found by this satellite will be 30 to 100 times brighter than the ones traced by the Kepler Space Telescope. Consequently, they are much more ideal for follow-up study by using telescopes on Earth and in space. For example, the James Webb Space Telescope will study some of the exoplanets found by the TESS after its launch in 2021. The Guest Investigator Program of the TESS is also operational. Padi Boyd, the Project Scientist of TESS at the Goddard Space Flight Center of NASA, acknowledged that in the following words:

“We were very pleased with the number of guest investigator proposals we received, and we competitively selected programs for a wide range of science investigations, from studying distant active galaxies to asteroids in our own solar system.”

Here is a short glimpse of how the TESS operates.