If you imagine a giant planet, you probably think of something dense and heavy, like Jupiter. But the universe holds surprises: NASA’s TESS space telescope has discovered two planets that are the size of Jupiter but weigh so little that scientists compare them to cotton candy. They’re called TOI-791 b and TOI-791 c, and they’re 1,113 light-years from Earth.
How is it possible that a huge planet weighs so little? To understand it, imagine taking a balloon the size of Jupiter and, suddenly, emptying it until there’s almost nothing left inside. TOI-791 b has the same diameter as Jupiter, but its mass is barely 3% of that of the giant of our solar system. Its companion TOI-791 c is even bigger, but contains only 5.9% of Jupiter’s mass. They are the most “puffed up” planets found so far.
The TESS telescope hasn’t seen them directly —they’re too far away for that— but it has detected them thanks to the small dimmings they cause when they pass in front of their star, something like when a fly passes in front of a streetlamp and you see the shadow. By analyzing those brightness changes, astronomers have calculated the size and mass of these planets. The next step will be to investigate what their atmospheres are made of to understand how worlds with such low density can form. For now, the cotton candy comparison is the best way to get an idea of how strange they are.
– Marta, for inteligencia intermitente.
