---
title: "Superpuffs: Scientists Find Giant Planets Lighter Than Cotton Candy"
description: "Astronomers have discovered a unique planetary system where the planets are the size of Jupiter but lighter than cotton candy. Their density is comparable to shaving foam, and they were found thanks to observations from Antarctica. 🔭☁️"
date: 2026-06-25T22:20:53.000Z
lang: en
url: https://xab.info/en/posts/superpuffs-scientists-find-giant-planets-lighter-than-cotton-candy
tags: []
publisher: "XAB.info"
---

# Superpuffs: Scientists Find Giant Planets Lighter Than Cotton Candy

![Artistic illustration of a blue super-puff planet against a starry background and its host star, showcasing a giant gaseous world with extremely low density](https://xab.info/media/2026/06/25/uchenye-nashli-planety-legche-sakharnoy-vaty/uchenye-nashli-planety-legche-sakharnoy-vaty-1.webp)

In the world of astronomy, a discovery has been made that forces a rethinking of conventional ideas about planetary structure. An international team of scientists, led by researchers from the University of Oxford, has discovered a unique planetary system where giants orbit with a density comparable to a cloud of shaving foam. The results of the study were published in the prestigious journal Monthly Notices of the Royal Astronomical Society.

The new worlds, designated TOI-791b and TOI-791c, are located in the constellation of the Flying Fish, at a distance of approximately 1110 light-years from Earth. Despite being comparable in size to Jupiter, their physical structure differs radically from the gas giant of our Solar System.

### The Physics of "Weightless" Giants

The main feature of these objects is their extremely low density. For comparison: the density of the cotton candy we are used to is about 0.05 g/cm³. The discovered planets turned out to be even lighter: TOI-791b has a density of 0.038 g/cm³, and TOI-791c — 0.047 g/cm³. The lead author of the study, George Dransfield, compared their structure to a piece of fresh shaving foam.

In numbers, this looks even more impressive: Jupiter is 28–35 times denser than these objects. At the same time, the mass of the "superpuffs" (as scientists call this class of objects) is closer to the mass of Neptune, but their atmospheres are inflated to incredible scales. Scientists assume that the planets consist mainly of hydrogen and helium.

Such worlds are extremely rare. Among the nearly 6300 confirmed exoplanets in the NASA catalog, less than 40 objects belong to the "superpuff" class. Finding two such planets in one system is a unique scientific stroke of luck, providing an opportunity to compare their characteristics.

### How to Weigh a Cloud?

Determining the mass of such "airy" objects became possible thanks to a unique combination of cosmic factors and ground-based technologies. The planets are locked in a 5:3 orbital resonance. While the inner planet makes five orbits around the star, the outer one manages to make exactly three.

Due to their close proximity, they constantly gravitationally push each other, which leads to micro-delays in the schedule of their passage (transit) in front of the star. By analyzing these shifts, astronomers were able to calculate the exact mass of the planets.

The location of the observations also played an important role. Due to the gigantic atmospheres, the transits of the planets last anomalously long — more than 11 hours. Recording them continuously was only possible with the help of the ASTEP telescope, located at the Concordia research station in Antarctica. The polar night provided scientists with months of continuous darkness necessary to obtain accurate data.

### The Main Mystery of Survival

The discovery poses a difficult question to science. According to the dominant theory, these planets formed on the distant and cold outskirts of their stellar system, where light gases settled around small solid cores. Later, they migrated closer to their star.

The main mystery is why the heat of the star has not yet burned up and blown into space these light atmospheres, barely held by gravity. To understand how such "weightless" giants could appear and survive, scientists plan to conduct a detailed study of their atmospheres using the James Webb Space Telescope.