Hunting for exoplanets is a complex yet exciting job that forefronts the search for habitability, but it’s definitely a time-consuming process. When an exoplanet candidate is detected, researchers have to observe it passing by its host star three times before they can officially confirm its existence. This isn’t a problem if the orbital period lasts a few days, weeks, or months, but it isn’t exactly effective if the planet takes years to transit its star. Luckily, a new method published in the journal Astronomy & Astrophysics allows astronomers to bypass the long wait period and verify the existence of some exoplanets after a single transit.
When a planet transits its host star, its luminosity temporarily decreases. By observing this decrease in luminosity three different times, researchers are able to confirm the transiting object’s orbital pattern and estimate its radius — key factors in determining its planetary status. The method works well for planets that orbit close to their host stars, but it isn’t ideal for planets like Earth, which would have to wait three years to have their planetary status confirmed. And forget about verifying a planet like Neptune, who takes about 165 years to orbit the Sun. Researchers just don’t have 500 years to wait around.
To eliminate the long waiting period, a team of astronomers at the University of Geneva (UNIGE) in Switzerland found an alternate method. They combed through K2 mission data from Kepler, NASA’s exoplanet-hunting space telescope, to find a star whose luminosity had dipped for a significant period of time — indicating a planet with a long orbital period. After analyzing hundreds of candidates, they came across EPIC248847494, a star whose light curve featured a celestial guest transiting for about 53 hours.