Three newly discovered hot Jupiters provide insights into late-stage planetary evolution

Star system: TOI-6564 | Distance from the Sun: 631 light years

Understanding how giant planets evolve is essential for building a complete picture of planetary systems. While many exoplanets have been found, studying their changes over time requires observing systems in different stages of development. A recent discovery has added three new gas giant planets — known as hot Jupiters — orbiting stars that are approaching the end of their main sequence, a critical but less studied phase of planetary life.

The planets, named TOI-3664 b, TOI-4034 b, and TOI-6564 b, were initially identified using data from the Transiting Exoplanet Survey Satellite (TESS). Following their detection, researchers performed extensive spectroscopic observations using ground-based instruments, including CARMENES, CORALIE, and MINERVA-Australis, to confirm their existence and measure their properties. All three planets are characterized by radii larger than that of Jupiter, but with lower masses, suggesting a slight inflation of their atmospheres as their host stars increase in luminosity.

To understand their evolutionary context, the research team conducted a detailed analysis to determine the ages of the host star systems. By combining multiple indicators such as stellar movement, rotation speeds, and lithium abundance, the researchers determined ages ranging from 4 to 9 billion years. Despite these differences in age, the stars share a similar evolutionary state because of their varying stellar masses. These three new worlds serve as important additions to the ongoing effort to map the 'age-ladder' of planetary evolution, providing valuable data to help astronomers understand how planets change as their host stars age.

Key findings
- Three new hot Jupiters (TOI-3664 b, TOI-4034 b, and TOI-6564 b) were discovered orbiting aging stars.
- All three planets are larger than Jupiter in radius but lower in mass, indicating atmospheric inflation.
- The host stars are nearing the end of their main sequence phase, providing a rare glimpse into late-stage planetary evolution.
- Determining the ages of these systems (ranging from 4 to 9 billion years) helps refine the 'age-ladder' of how planetary systems develop over time.

Scientific study

TOI-3664 b, TOI-4034 b & TOI-6564 b: Three new hot Jupiters around stars approaching the terminal age main sequence (external link)