Scientists have made a groundbreaking discovery of two rare ‘super-puff’ planets, named TOI-791 b and TOI-791 c, which are lighter than cotton candy. These planets are among the lowest-density giant planets ever detected and are believed to have formed together from the same disc of gas and dust surrounding their young star.

Unique Characteristics

The two planets are ‘siblings’ and are locked in a rare gravitational relationship known as a 5:3 mean-motion resonance. This means that for every five orbits completed by the inner planet, the outer planet completes almost exactly three. The gravitational interaction between the planets causes them to repeatedly ‘tug’ on one another, producing measurable shifts in the timing of their transits across the host star.

The research team, led by University of Oxford scientists, used observations from telescopes around the world to measure the planets’ densities. They found that TOI-791 b has a density of just 0.038 grams per cubic centimeter, while TOI-791 c has a density of 0.047 grams per cubic centimeter. By comparison, Jupiter’s average density is 1.33 grams per cubic centimeter, which is around 28 to 35 times greater.

Formation Theories

Astronomers are still debating how super-puff planets form, but one leading theory suggests that they possess enormous hydrogen- and helium-rich atmospheres that make up a significant fraction of their total mass. The researchers intend to carry out further investigations to understand more about how the planets formed and to rule out some of the leading super-puff explanations.

Original reporting: KTBS 3 (Shreveport) — read the source article.