CHEOPS observations reveal planetary densities and atmospheric evolution in V1298 Tau system

Star system: V1298 Tauri A | Distance from the Sun: 352 light years

The young V1298 Tau planetary system, estimated to be between 10 and 30 million years old, provides a window into the early stages of planet formation. Recent observations focused on the three innermost planets of the system, refining measurements of their sizes and physical properties to better understand how young worlds develop their atmospheres and internal structures.

Data from the CHEOPS space telescope allowed for high-precision measurements of the planetary radii, improving existing estimates by 30 to 71 percent. By combining these findings with measurements of transit-timing variations—slight changes in the time it takes for a planet to cross in front of its star caused by the gravitational tugs of neighboring planets—researchers calculated the bulk densities of these worlds, which range from 0.06 to 0.23 grams per cubic centimeter.

The findings show that the innermost planet, designated planet c, is significantly denser than the outermost planet in the observed group. This difference in density suggests that the planets have varying proportions of gas and solid material, indicating that their atmospheres are evolving differently. Furthermore, simulations of the system's orbital architecture show no sign that these planets are trapped in resonance, meaning their gravitational interactions do not force them into specific, repeating patterns. The orbital state of the system appears stable and requires no history of past violent dynamical changes to explain its current arrangement.

Key findings
- Planetary radii for the inner V1298 Tau planets were determined with significantly higher precision.
- Bulk densities for the planets were measured between 0.06 and 0.23 grams per cubic centimeter.
- Planet c is confirmed to be denser than the outermost observed planet.
- Varying densities across the system point toward different rates of atmospheric evolution.
- Orbital simulations indicate the system is not currently influenced by mean-motion resonances.

Scientific study

CHEOPS observations of V1298 Tau: updated planetary densities and implications on the early evolution of the young system (external link)