A newly discovered planet, dubbed TOI-1408 c, is leaving astronomers scratching their heads while potentially unlocking details about how planets form.
This exoplanet is located around 455 light-years away and engages in a peculiar orbital dance with another nearby planet, TOI-1408 b, according to a study published in The Astrophysical Journal Letters.
TOI-1408 c has a mass about **eight times that of Earth** and orbits its star with a varying period, creating a unique relationship with TOI-1408 b, a “hot Jupiter” that takes about half the time to make its own orbit.
Co-author Judith Korth from Lund University commented, “The behavior of this small planet is unusual, leading to significant variations in its transit timings. This challenges our current understanding of planetary systems’ formation and stability.”
Interestingly, astronomers can detect these planets as they pass in front of their star. However, TOI-1408 c showcases anomalies in both the timing and duration of these transits, referred to as transit timing variations (TTVs) and transit duration variations (TDVs).
The study reveals that TOI-1408 c’s TTV amplitude is the highest recorded yet, making up 15 percent of its orbital period, likely due to its synchronized 2:1 energy ratio with the other planet.
The researchers speculate there might be a third, undiscovered planet involved, contributing further to these unusual variations.
They stated, “The dynamics of this system and the potential for a third body call for more observational efforts to further elaborate on the behavior and long-term stability of these orbits.”
The ongoing research aims to deepen our comprehension of multi-planet systems, particularly those featuring a classic “hot Jupiter” alongside smaller companions. Korth expressed optimism that these insights will pave the way for discovering new planets and enhancing our understanding of the diverse arrangements of planetary systems within our galaxy.
Reference
Korth, J. et al. (2024). TOI-1408: Discovery and Photodynamical Modeling of a Small Inner Companion to a Hot Jupiter Revealed by Transit Timing Variations. The Astrophysical Journal Letters, 971(2), L28. https://doi.org/10.3847/2041-8213/ad65fd