'From Dwarf to Giant': NASA's TESS discovers a massive exoplanet in a binary star system

Produced by: Tarun Mishra

Discovery of a Giant Exoplanet

An international team of astronomers from the GEMS (Giant Exoplanets around M-dwarf Stars) survey has detected a massive exoplanet, TOI-6383Ab, in a binary star system. The system, located 560 light-years from Earth, consists of two red dwarf stars, raising questions about how giant planets form around low-mass stars.

Exoplanet’s Characteristics

The planet, TOI-6383Ab, has a size and mass similar to Jupiter, with an orbital period of just 1.79 days around the primary star, TOI-6383A. This finding is significant as it is unusual for giant planets to form around such low-mass, cooler stars.

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Binary Star System Composition

The TOI-6383 system includes two red dwarf stars. The primary star, TOI-6383A, has about 46% of the Sun’s mass and a surface temperature of 3,444 K, while the companion star, TOI-6383B, is 20.5% as massive as the Sun, with a temperature of 3,121K.

Challenges to Planet Formation Theories

The discovery of this massive exoplanet challenges traditional models of planet formation around red dwarfs. Red dwarf stars typically have less material in their protoplanetary disks, which would seemingly limit the formation of giant planets, raising questions about existing models.

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Two Competing Planet Formation Models

The discovery helps astronomers test two theories of planet formation. The core-accretion model, which suggests planets form by accumulating mass around a core, faces challenges in explaining the formation of giant planets around red dwarfs. The rapid formation model, where planets form from collapsing clumps of gas in the disk, could better explain these findings.

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Role of NASA’s TESS in Detection

NASA's Transiting Exoplanet Survey Satellite (TESS) played a key role in identifying TOI-6383Ab. The GEMS team used the Transit Method to detect periodic dips in the star's brightness, indicating the presence of the planet. Ground-based telescopes confirmed the planet through photometry and radial velocity measurements.

Expanding the Inventory of Massive Exoplanets

To date, only 20 giant exoplanets have been discovered around M-type red dwarfs. The GEMS survey aims to double this number to at least 40, providing a larger sample size for testing planet formation theories around these stars.

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Implications for Future Research

The discovery of TOI-6383Ab offers valuable insights into the processes that lead to the formation of massive planets in red dwarf systems. As more exoplanets are found, astronomers will gain a better understanding of how these planets form, refining current models and contributing to the broader study of planetary systems.

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