You can’t help but wonder what unknown worlds and, perhaps, advanced civilizations might be awaiting discovery within the final record of the Kepler spacecraft’s full field of view before the depletion of fuel permanently ended its work. NASA retired the iconic spacecraft on Oct. 30, 2018, to a safe orbit. The Kepler field of view represents 1/400 of the Milky Way Galaxy and its 100 billion stars.
The “last light” image taken on Sept. 25 represents the final image of Kepler’s remarkable journey of data collection that rivals that of the Hubble Space Telescope in its contribution to human knowledge and awareness since its launch nine and a half years earlier when the spacecraft captured its “first light” image. Kepler went on to discover more than new 2,600 worlds beyond our solar system and statistically proved that our galaxy has more planets than stars. Only twenty years ago, scientists were debating the very existence of alien planets.
The blackened gaps in the center and along the top of the image are the result of earlier random part failures in the camera. Due to the modular design, the losses did not impact the rest of the instrument.
For this final field of view, Kepler’s last observation campaign in its extended mission, the telescope was pointed in the direction of the constellation Aquarius where it observed the TRAPPIST-1 system with its seven rocky planets, at least three of them believed to be temperate worlds. Another target was the GJ 9827 system, a nearby bright star that hosts a planet that is considered a prime opportunity for follow up observations with other telescopes to study an atmosphere of an alien world.
This Kepler’s view of GJ 9827, a star around which Kepler previously detected three orbiting planets. Because the system is relatively close at 97 light-years away, it is considered an excellent target for studying exoplanet atmospheres. NASA/Ames Research Center
Although Kepler’s transmitters have been turned off and it is no longer collecting science, its data will be mined for many years to come.
Fortuitously, Kepler’s field of view also slightly overlapped with NASA’s new planet-hunter, the Transiting Exoplanet Survey Satellite, or TESS, affording astronomers the chance to compare and improve their understanding of the data received from the two spacecraft. Although Kepler’s transmitters have been turned off and it is no longer collecting science, its data will be mined for many years to come.
The image blow shows the telescope’s “first light” — a full field of view of an expansive star-rich patch of sky in the constellations Cygnus and Lyra stretching across 100 square degrees, or the equivalent of two side-by-side dips of the Big Dipper.
Kepler was designed to hunt for planets like Earth. Of the approximately 4.5 million stars in the region pictured here, more than 150,000 were selected as candidates for Kepler’s search. The mission spent three-and-a-half years staring at these target stars, looking for periodic dips in brightness. Such dips occur when planets cross in front of their stars from our point of view in the galaxy, partially blocking the starlight.
The area in the lower right of the image is brighter because it is closer to the plane of our galaxy and is jam-packed with stars. The area in upper left is farther from the galactic plane and contains fewer stars. The image has been color-coded so that brighter stars appear white, and fainter stars, red. It is a 60-second exposure, taken on April 8, 2009, one day after the spacecraft’s dust cover was jettisoned.
The Daily Galaxy, Max Goldberg via NASA/Ames Research Center