Unearthing Hidden Double‑Star Planets
For decades, astronomers believed that worlds orbiting two suns could only be spotted when the planets happened to pass directly in front of both stars from Earth’s viewpoint. That stringent geometry limited discoveries to a handful of “Tatooine” analogues. A team from Australia has turned that assumption on its head, revealing 27 new candidates without ever seeing the planets themselves.
Turning the Problem Upside‑Down
Instead of searching for the planet’s silhouette, the researchers examined the subtle gravitational tug a planet exerts on its host binary. A planetary companion nudges the two stars, causing the timing of their mutual eclipses to drift ever so slightly. In a perfectly isolated binary, eclipses recur like clockwork; any minute deviation points to an unseen third body.
Mining TESS Data for Anomalies
The team sifted through roughly 1,600 eclipse‑timing measurements collected by NASA’s Transiting Exoplanet Survey Satellite (TESS). After eliminating variations explainable by stellar activity or orbital mechanics, 36 systems displayed unexplained “wobble.” In 27 of those, the pattern matched what a planet would produce.
What Kind of Worlds Are We Looking At?
Most of the signals suggest planets lighter than Jupiter, with a few possibly as massive as Neptune. If confirmed, the Neptune‑mass objects would set a record as the lightest planets known around binary stars. The data, however, cannot yet distinguish whether a low‑mass planet close to the stars or a heavier object farther out is responsible for the timing shift – both scenarios generate comparable signatures.
Beyond Planets: Brown Dwarfs and Stellar Companions
Six of the remaining candidates appear too massive to be planets, hinting at brown dwarfs or even faint stellar companions. This blurs the line between giant planets and “failed” stars, a gray area that astronomers continue to explore.
Confirming the Findings
To move from candidate to confirmed exoplanet, the researchers will apply the radial‑velocity method, measuring the stars’ back‑and‑forth motion caused by the hidden companion. Fortunately, all 27 systems are bright enough for ground‑based spectrographs on large telescopes, making follow‑up observations feasible.
The Road Ahead
The catalog used for this study contains over two million binary systems, suggesting a reservoir of countless more Tatooine‑like worlds awaiting discovery. While the iconic desert planet of Star Wars remains a fictional landmark, the real universe may be teeming with similar double‑sun landscapes.
Source: https://scientias.nl/astronomen-vinden-27-nieuwe-tatooine-werelden-zonder-ze-ooit-te-hebben-gezien/
