Infant planet TOI-837 b shows a mildly misaligned orbit around its star

Star system: TOI 837 | Distance from the Sun: 465 light years

TOI-837 b is a young, Saturn-sized planet located in the IC 2602 cluster, which is only 35 million years old. By studying the spin-orbit obliquity—the angle between the axis of the planet's orbit and the axis of the host star's rotation—researchers can determine how planets migrated to their current positions. This planet is the first younger than 100 million years observed to have a measurable misalignment, providing a rare look at planetary evolution.

The planet was observed during transit using the ESPRESSO instrument at the Very Large Telescope to measure the Rossiter-McLaughlin effect. This effect occurs when a planet passes in front of a star and blocks different parts of the rotating stellar surface, creating a specific shift in light patterns that reveals the alignment of the orbital plane.

The data confirms a prograde motion, where the planet orbits in the same direction as the star rotates, but with a slight tilt. This configuration suggests that the planet's orbit was likely affected by forces within the original gas disc that formed the planetary system, rather than through violent gravitational interactions later in its life.

Key findings
- TOI-837 b is the first planet younger than 100 million years with a confirmed misaligned orbit.
- The planet exhibits prograde motion with a measured tilt relative to the star's equator.
- Observations were conducted using high-precision radial velocity measurements via the ESPRESSO instrument.
- The misalignment suggests the planet's path was influenced by early disc-driven migration rather than later gravitational scattering.

Scientific study

The 35-Myr old infant planet TOI-837 b has a mildly misaligned orbit (external link)