Scientists discover 27 potential new planets that orbit two stars in solar systems far, far away – Image for illustrative purposes only (Image credits: Unsplash)
Astronomers have identified 27 candidate planets circling pairs of stars, more than doubling the tally of potential circumbinary worlds known to date. This discovery, highlighted on May the 4th – Star Wars Day – evokes the double sunsets of Luke Skywalker’s home planet, Tatooine. The findings emerge from NASA’s Transiting Exoplanet Survey Satellite (TESS) data and offer fresh insights into how planets form amid the gravitational dance of binary stars.[1][2]
A Clever New Detection Technique
Researchers turned to an innovative approach called apsidal precession to spot these candidates. In binary star systems where eclipses occur, the stars’ orbits wobble slightly due to gravitational influences. When TESS observed unexpected rates of this precession in 71 out of 1,590 eclipsing binaries, the team ruled out effects from relativity, tides, or star rotation.[2]
Excess precession pointed to unseen companions pulling on the stars. After careful analysis, 27 systems yielded planet-mass candidates with minimum masses between 0.038 and 0.70 Jupiter masses. Another six showed signs of heftier companions, possibly brown dwarfs. The method validated itself on a known circumbinary planet in the system TIC 172900988, matching predicted precession rates closely.[2]
Characteristics of These Elusive Worlds
The candidate planets cluster near the critical stability radius, the closest orbit where they can endure the binary stars’ pull without being ejected. Binary periods in these systems range from 4.28 to 129.32 days, suggesting compact setups similar to those probed by earlier missions. Yet properties remain uncertain: a low-mass planet close in or a heavier one farther out could produce the same signal.[2]
Over half the candidates allow for sub-Jupiter masses, some as low as Neptune-sized. Light-travel-time effects appeared in 31 systems, hinting at wider orbits. This degeneracy underscores the candidates’ status – they await confirmation through radial velocity measurements or other techniques.[1]
Building on a Decade of Circumbinary Discoveries
Prior to this work, NASA’s Kepler and TESS missions confirmed 14 transiting circumbinary planets, all closely aligned and coplanar with their host binaries. Other methods like eclipse timing variations added a handful more, bringing the recognized total to around 18. Transit searches favored edge-on views and tight orbits, leaving misaligned or distant worlds undetected.[2]
These new candidates expand the sample dramatically. Theoretical models predict circumbinary planets form in situ but face disk instabilities in binaries. Observations near the stability edge align with simulations favoring coplanar survivors. For context, over 6,000 exoplanets orbit single stars, highlighting how rare – and challenging – double-star worlds remain.
- Previous confirmed transiting CBPs: 14 from Kepler/TESS
- Total prior candidates/known: ~18
- New candidates: 27 planet-mass + 6 companions
- Data source: TESS on 1,590 Gaia eclipsing binaries
Path Forward for Twin-Star Planets
The research team, led by Margo Thornton from the University of New South Wales, calls for follow-up observations. Bright targets (magnitudes under 13.5) suit radial velocity surveys to measure true masses and orbits. Future TESS data, spanning over seven years, and Gaia DR4 astrometry will refine the catalog.[2]
Longer baselines could reveal more perturbers or variable dynamics. Combining methods might map demographics, testing formation theories and ejection rates into free-floaters. As tools improve, the galaxy’s binary-hosted planets may prove more common, reshaping views of planetary diversity.
This announcement on Star Wars Day reminds us how science turns science fiction into fact – one wobbling orbit at a time. While confirmation lies ahead, these 27 candidates invite wonder about distant double sunrises and the universe’s hidden architectures.