Pesquisadores of Universidade of Nova Gales of Sul identified 27 new circumbinary planet candidates by analyzing data from NASA’s TESS satellite. The discovery, published in the journal Monthly Notices of the Royal Astronomical Society, used an innovative method based on perihelion displacement in eclipsing binary stars, bypassing limitations of the conventional transit method. The candidates orbit systems of two stars that gravitate around each other, representing a significant advance in detecting worlds whose orbital geometry would make them invisible to ground-based telescopes using traditional techniques.
Limitações of the transit method and the need for innovation
The transit method, the dominant technique for discovering exoplanets, identifies planets by the slight reduction in brightness they cause when they pass in front of their stars. Funciona accurately when the planet’s orbital plane is aligned perpendicularly with the perspective of Terra. Porém, for circumbinary planets this geometric requirement becomes extremely restrictive and excludes an entire class of worlds from observation.
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If a planet’s orbital plane is tilted by just one degree relative to the plane of the binary orbit, transits do not occur at regular, detectable intervals. Isso means that circumbinary planets with highly inclined orbits remained invisible to observers. The team recognized that previous observational data reflected an intrinsic bias: only planets with specific orientations were found, creating an incomplete view of the actual population of worlds in binary systems.
Deslocamento of perihelion as a detection tool
The new method took advantage of a phenomenon called perihelion shift, the gradual rotation of the elliptical orbits of celestial bodies. In our solar system, the perihelion of Mercúrio, detected since the 19th century, illustrates this classic effect. The team analyzed 1,590 eclipsing binary stars observed continuously by TESS for at least two years, looking for gravitational signatures of planetary objects.
Quando an outer planet exerts gravitational influence on a binary system, subtly alters the timing of eclipses, the precise instant at which the two stars obscure each other. With Medindo accurately analyzing the temporal variations of these eclipses, researchers identified gravitational signatures of planetary objects. The strategy revealed candidates that would go completely unnoticed by conventional transit techniques, expanding the view on the real population of circumbinary planets.
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Características of the 27 discovered candidates
The masses of detected objects vary significantly over a wide spectrum. Researchers found worlds with different characteristics:
- Mínimo: approximately 12 times the mass of Terra
- Máximo: about 3,200 times the mass of Earth, approximately 10 times the mass of Júpiter
- Distribuição: broad spectrum between worlds similar to Terra and gas giants
Nenhuma definitive confirmation has been achieved to date. Additional Observações with the radial velocity method using ground-based telescopes will be needed to validate the candidates. Essa technique detects planets indirectly by the wobble of host stars caused by planetary orbit, measuring color changes in starlight that occur as stars move toward or away from Terra.
Significado for future planetary discoveries
Benjamin Montet, an associate professor at UNSW who is part of the research, highlights that abundant, long-term observational data from TESS made it possible to calculate extremely subtle effects. The satellite, originally designed to capture planetary transits, demonstrated an unexpected ability to reveal worlds whose transits would never be observed from Terra. Esse result is particularly notable because it highlights that conventional methodology underestimates the true population of exoplanets.
Planetas with diverse orbits and unfavorable geometries goes unnoticed, suggesting that the universe contains more planetary systems than previous research has revealed. If future observations confirm the existence of these candidates, it will pave the way for deeper understanding of planet formation processes in Via Láctea and reposition how astronomers search for distant worlds.