Scientists are using a new approach to find the mysterious — if it exists — Planet Nine by hunting for its heat signature instead of reflected light. Using data from Japan’s AKARI space telescope, a team of researchers identified two promising candidates using their thermal detection method which is more effective than optical searches alone. But could these distant heat sources finally prove the existence of our Solar System’s most elusive world, or will they turn out to be yet another false alarm in the decades long search?

As NASA’s New Horizons spacecraft traveled through the Kuiper Belt at a distance of 438 million miles from Earth, an international team of astronomers used the far-flung probe to conduct an unprecedented experiment: the first-ever successful demonstration of deep space stellar navigation.

A paper describing the results was accepted for publication in The Astronomical Journal. The pre-print is available on the server arXiv.

As a proof-of-concept test, the researchers took advantage of the spacecraft’s unique vantage point as it traveled toward interstellar space to image two of our nearest stellar neighbors, Proxima Centauri, which is 4.2 light-years from Earth, and Wolf 359, which is 7.86 light-years away.

Using the Keck Planet Finder (KPF), the observatory’s most advanced instrument, the team measured oscillations within the star, subtle vibrations once thought undetectable. The results, published in The Astrophysical Journal.