Almost five years post-retirement, the Kepler Space Telescope continues to advance our knowledge of the cosmos. A group of astronomers has recently unveiled three exoplanets from the last light captured by this seasoned observatory, hidden within its data archives from 2018.
Kepler, launched into space in 2009, had one primary mission – to seek out new worlds. During its nine-year journey around the sun, the telescope identified over 2,600 exoplanets. A few of these were found within the habitable “Goldilocks Zone,” indicating the potential of life-supporting conditions.
Kepler’s journey ended in October 2018 due to a lack of fuel, but its data continues to yield cosmic discoveries. This week, astronomers revealed the detection of three planets observed by the telescope just before it was retired. The research was published in the Monthly Notices of the Royal Astronomical Society.
These exoplanets were noted during Kepler’s final observational series, known as the K2 Campaign 19. As the telescope neared the end of its service, maintaining its position became a challenge, making it difficult to record clear data. However, a week’s worth of high-quality data was secured by the campaign before the signal became excessively noisy. “Kepler’s capacity to detect exoplanets, even as it was virtually running on fumes, is truly astonishing,” the team noted in their report.
The research was further aided by the Visual Survey Group, a citizen scientist collective that analysed the light curves from stars observed by Kepler during the campaign. A decrease in the light curve is usually indicative of an exoplanet’s transit. Kepler, along with other exoplanet seekers like the TESS spacecraft, utilizes this method to search for exoplanets.
The astronomers did not physically observe the planets, rather the indications of three stars dimming from Kepler’s perspective, implying the transit of an orbiting body. Two of these bodies were confirmed as exoplanets, while the third remains a candidate.
According to MIT News, the confirmed planets are “hot mini-Neptunes,” a few times larger than Earth and closely orbiting their host stars. Both are approximately 400 light-years away from Earth. The candidate planet is larger, nearly four times the size of Earth, and located about 1,200 light-years away.
The University of Wisconsin at Madison astronomer and lead author of the study, Elyse Incha, told MIT News, “These are the last planets chronologically observed by Kepler, but all of the telescope’s data is invaluable. We aim to ensure none of this data goes to waste, as there are still numerous discoveries to be made.”
The baton now passes to the Webb Space Telescope as it continues the search for exoplanets, thereby augmenting our understanding of the diverse worlds beyond our solar system. The National Academies of Sciences, Engineering, and Medicine’s latest decadal survey highlights the pursuit of habitable worlds as a prime scientific objective.
