Astronomers Discover 27 Potential Circumbinary Planets Using Novel Technique
A team of astronomers, led by researchers at UNSW Sydney, has identified 27 potential circumbinary planets—planets that orbit two stars—using a new method based on orbital mechanics. The findings were published in the Monthly Notices of the Royal Astronomical Society on May 4.
Detection Method
The candidates were identified by analyzing data from NASA's Transiting Exoplanet Survey Satellite (TESS). The team studied 1,590 binary star systems, tracking variations in the timing of eclipses between the two stars over time.
Changes in these eclipse timings that cannot be explained by general relativity or stellar interactions suggest the gravitational influence of a third body, likely a planet.
This marks the first large-scale application of this specific detection method for finding planets.
Candidate Properties
The potential planets range in size from approximately the mass of Neptune to up to 10 times the mass of Jupiter. Their distances from Earth vary significantly:
- Closest candidate: approximately 650 light-years away
- Farthest candidate: approximately 18,000 light-years away
The candidates are distributed across both the northern and southern skies.
Significance and Context
Prior to this study, only 18 circumbinary planets had been confirmed, compared to over 6,000 exoplanets identified in single-star systems. The method used in this study has a crucial advantage: it can detect planets that are not aligned with Earth's line of sight, a significant limitation of the traditional transit method.
Based on their sample, the researchers estimate that roughly 2% of binary star systems may host such planets.
This suggests that thousands to tens of thousands of circumbinary planets could exist in the galaxy, with the potential for many more to be found through future surveys.
Next Steps
The research team plans to:
- Conduct spectroscopic observations
- Collaborate with researchers in the United States, the United Kingdom, and China to confirm or rule out the 27 candidates
- Apply the method to larger samples of binary star systems
- Run simulations to better understand planet formation and evolution in these environments
Key Statements
Margo Thornton, lead author and PhD candidate at UNSW Sydney, stated that the method could help uncover a large population of hidden planets, particularly those that do not align perfectly with Earth's line of sight.
Ben Montet, associate professor at UNSW Sydney, noted the potential to find thousands of planets using data from the upcoming Vera C. Rubin Observatory's Legacy Survey of Space and Time.