TESS planet-hunter reaches the first light | Space

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For any new telescope or astronomical camera, the first light is a motif of celebration. On September 17, 2018, NASA released the official footage in first light of its most recent planetary hunter, called the Exoplanet Survey Satellite, or TESS. Launched last April, TESS is the successor of the highly successful Kepler mission, which has discovered some 2,300 exoplanets in its lifetime. The image above is a part of the capture at the first light of TESS; you can see the whole picture below. TESS, which orbits around the Earth in a very elliptical and very stable orbit (more about this below), has captured a slice of the southern sky for its image in first light. NASA said:

This first-light scientific image captures a multitude of stars and other objects, including systems known to have exoplanets.

TESS acquired the complete image below using the four cameras for a period of 30 minutes on Tuesday August 7, 2018. NASA explained:

The black lines on the image are spaces between the camera detectors. The images include parts of a dozen constellations, from Capricornus to Pictor, and two large and small magellanic clouds, the closest galaxies to ours. The small bright dot above the small Magellanic cloud is a globular cluster – a spherical collection of hundreds of thousands of stars – called NGC 104, also known as 47 Tucanae because of its location in the constellation southern Tucana, the Toucan. Two stars, Beta Gruis and R Doradus, are so bright that they saturate an entire column of pixels on the detectors of the second and fourth TESS cameras, creating long spikes of light.

George Ricker, TESS Principal Investigator at the Kavli Institute for Astrophysics and Space Research at MIT Cambridge, said:

This band of the southern hemisphere of the sky includes more than a dozen stars that we know have planets in transit, according to previous studies by observatories on the ground.

Like Kepler, TESS will monitor the transits, which occur when a planet passes in front of its star from the viewpoint of the observer, causing a periodic and steady decline in star brightness.

According to NASA, more than 78% of confirmed exoplanets, including those found by Kepler, were found using transits.

Unlike Kepler – who had a fixed field of view – TESS will search for exoplanets in some 85% of the Earth's sky. Scientists have divided the sky into 26 sectors. TESS will use its four wide-field cameras to map 13 areas encompassing the southern sky during its first year of observation and 13 areas of northern skies during the second year.

And here is another difference between Kepler and TESS. Most of the Kepler exoplanets orbit 300 to 3 000 light years from Earth. TESS will focus on much closer stars – between 30 and 300 light-years – and some 30 to 100 times brighter than Kepler's targets.

The brightness of these target stars will allow future researchers to use spectroscopy, the study of absorption and light emission, to determine the mass, density and atmospheric composition of a planet. Water and other key molecules in its atmosphere can give us clues about a planet's ability to house life.

In fact, TESS captured an image tested last May, as it swept the moon, almost a month to the day after the April 18 launch of the machine from Cape Canaveral Air Force Base in Florida. See the previous TESS test image here.

And why did TESS sweep the moon? It was to accomplish a gravitational assistance that moved TESS into its current orbit, very stable and very interesting. The video below explains more about this.

Bottom line: NASA has released the first official light image of its new planet fighter, TESS.

Via NASA