Revealing Cosmic Secrets: Astrophysicist Curates Comprehensive Index of Planet-Bearing, Tri-Star Systems

University of Texas’s planetary physicist has spearheaded a study that assembles an all-encompassing inventory of every identified planet-bearing three-star system, taking into account various planetary orbits and resolving past debates. The research infers that planets within these triple-star systems, which constitute around 0.5% of all recognized planets, primarily resemble Jupiter and accentuates the complexities in understanding their creation and orbital steadiness.

Triple-star systems consist of a binary star system with a third star orbiting this pair.

The recent study, headed by Manfred Cuntz from The University of Texas at Arlington, meticulously details every known triple-star system with planet-hosting capabilities.

The endeavor, “An Early Catalog of Planet-hosting Multiple-star Systems of Order Three and Higher,” delivers an exhaustive bibliographic review of planet-bearing, three-star systems.

The Astrophysical Journal Supplements, an esteemed publication of the American Astronomical Society, recently featured the research. The co-authors of the paper are UTA alumni G.E. Luke, Matthew Millard, and Lindsey Boyle, and doctoral candidate Shaan D. Patel.

The study presents a system classification that encompasses different types of planetary orbits, among other factors. Additionally, it scrutinizes previous controversies and retractions of planets based on the criteria defining a planet-hosting triple-star system.

In contrast to our solar system, where all planets revolve around a solitary star, around 100 known planets are part of binary star systems, according to the research.

Cuntz explained, “The count of planets discovered in higher-order systems remains relatively modest—roughly 40 for both triple and quadruple systems, with the exact count contingent upon whether certain contentious or unverified cases are included.” He added, “The confirmed count of planets in three-star systems is approximately 30, nearly 0.5% of the total known planets, making these planets quite extraordinary.”

The NASA Kepler Space Telescope, operational from 2009-18, significantly contributed to the discovery of planet-hosting, three-star systems, noted Cuntz. With the capabilities of the James Webb Space Telescope launched in 2021, scientists anticipate an increase in the known systems.

The research reveals that the vast majority of planets within triple-star systems resemble Jupiter in being gas giants, with their host stars being relatively massive compared to typical main-sequence stars. Nevertheless, some Earth-mass planets have also been identified.

The complexities of a triple-star system can be broken down into two categories, each traversing a comparatively large orbit around the system’s center of mass. Generally, in a triple-star system, two stars form a close binary pair, and the third orbits this duo from a more significant distance. More than three-star systems are likely to result in increasingly complex orbital configurations.

Cuntz acknowledged, “The existence of planets in triple-star systems presents a formidable theoretical challenge, both in terms of their formation and orbital stability.” He added, “These issues will form a strong impetus for future research at UTA, involving student participation.”

Citation: “An Early Catalog of Planet-hosting Multiple-star Systems of Order Three and Higher” by M. Cuntz, G. E. Luke, M. J. Millard, L. Boyle, and S. D. Patel, 5 December 2022, The Astrophysical Journal Supplement Series.
DOI: 10.3847/1538-4365/ac9302

Frequently Asked Questions (FAQs) about Triple-Star Systems

More about Triple-Star Systems

• University of Texas at Arlington
• The Astrophysical Journal Supplement Series
• NASA Kepler Space Telescope
• James Webb Space Telescope