The planet, TOI-849 b, is the most massive Neptune-sized planet detected to date, and the first to have a density that is comparable to Earth.
“We’re really puzzled about how this planet formed,†says Chelsea Huang, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research, and a member of the TESS science team.
As the TESS team proposes in the new study, over time, much of the planet’s gassy envelope may have been blasted away by the star’s radiation — not an unlikely scenario, as TOI-849 b orbits extremely close to its host star
According to this model, the Neptune-sized planet that TESS discovered may be the remnant core of a much more massive, Jupiter-sized giant
“If this scenario is true, TOI-849 b is the only remnant planet core, and the largest gas giant core known to exist,†says Huang