A captivating celestial dance unfolds in a distant planetary system as NASA's TESS (Transiting Exoplanet Survey Satellite) unveils a rare gravitational lockstep among six planets.
These planets, akin to sub-Neptunes, encircle a star smaller and cooler than our sun, orchestrating a rhythmic waltz that astounded astronomers.
Peculiar Planetary Arrangement
This peculiar planetary arrangement, exhibiting a gravitational resonance, is a rarity in the cosmos. The innermost planet completes three orbits for every two orbits of the next planet in line, creating a distinctive 3/2 resonance. According to NASA, this rhythmic pattern also extends to the four closest planets.
On the outer front, a 4/3 resonance occurs, with the fourth planet making four orbits for every three of the next one out. The consistency of these resonant orbits suggests that the planets have adhered to this synchronized dance since the formation of the system billions of years ago.
This stability is an anomaly in planetary system formation, where early upheavals, collisions, and rearrangements are expected. The enduring rhythm of this planetary ballet raises intriguing questions about the system's formation process.
The resilient stability observed indicates that the planetary system avoided the tumultuous events often associated with early planet formation. Smash-ups, collisions, mergers, and breakups, common in the formative years of planetary systems, appear to have been notably absent in this cosmic choreography.
The exacting precision of the 3/2 and 4/3 resonances has remained virtually unchanged since the system's inception, offering a unique insight into its early evolution.
To unravel this celestial mystery, astronomers relied on NASA's TESS, which tracks the minute eclipses, or transits, that planets create as they pass in front of their host stars.
The initial data from TESS hinted at the presence of multiple transits around the star HD 110067, but discerning the number of planets and their orbits proved challenging.
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The Breakthrough on Six Planets System
The breakthrough came when scientists pinpointed the two innermost planets with 9-day and 14-day orbital periods, respectively. Further assistance from CHEOPS (Characterising ExOPlanets Satellite), operated by the European Space Agency, identified a third planet with a 20-day orbit.
Upon analyzing the orbits of these three planets, researchers identified a 3/2 resonance, prompting the search for additional planets. Extensive mathematical calculations and gravitational considerations led to the prediction of a fourth planet with a 31-day orbit, followed by a fifth planet with a 41-day orbit and a sixth planet with an orbit only shy of 55 days.
The discovery team encountered a hurdle as some TESS observations were seemingly unusable due to excessive light scattered by Earth and the moon. However, a computer code developed by scientist David Rapetti enabled the recovery of transit data previously thought to be lost.
This recovery confirmed the predicted orbits of the two outer planets, completing the cosmic ensemble of six planets dancing to the beat of a rare gravitational rhythm. The team's findings were published in the journal Nature.
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