Planet as light as cotton candy

Astronomers have discovered a strange planet, giant in size but the second-lowest density ever found by astronomers. The newly discovered celestial body, called WASP-193b, has a density of only 0.059 grams of matter per cubic centimeter, equivalent to… a cotton candy.

The density of matter on WASP-193b is equivalent to 1/7 of the mass of Jupiter . You may not know, Jupiter is 50 times larger than Earth, but the density of matter is only about 1% of Earth.

Professor Julien de Wit from the Massachusetts Institute of Technology, co-author of the study, said the planet is so light that it is difficult to compare it to a mass of matter. And it is made up mainly of air, so light as cotton that it has been compared to cotton candy.

WASP-193b is located about 1,181 light-years from Earth and was first discovered in 2023 by the Wide Angle Search for Planets (WASP) project.

The study found that WASP-193b takes 6.2 Earth days to orbit a star the size of the Sun, at a distance equivalent to 7% of the distance from Earth to the Sun. WASP-193b completes one rotation every 6.2 Earth days.

Astronomers say WASP-193b is “light as a feather” because its mass is equivalent to 0.139 times that of Jupiter, but it is 1.5 times larger than Jupiter. In terms of density, WASP-193b has 0.059 grams/cm3, Jupiter has 1.33 grams/cm3, and Earth has 5.51 grams of matter per cubic centimeter of space.

So WASP-193b is comparable to a cotton candy or a disposable Styrofoam cup.

WASP-193b is the second-lowest-density planet ever discovered, behind Kepler-51d, which is much smaller, said study co-author Khalid Barkaoui.

Researchers believe that WASP-193b is made up of hydrogen and helium, but they have not yet explained why WASP-193b is so large.