Astronomers have identified two giant exoplanets with densities lower than cotton candy, making them the lightest known planets of their size. Located 1,110 light-years away in the constellation Volans, these “super-puffs” possess a physical consistency comparable to shaving foam, according to George Dransfield of the University of Oxford. The findings, published in Monthly Notices of the Royal Astronomical Society, reveal these worlds are as large as Jupiter but significantly less dense, providing new data on how planetary systems evolve.
How do astronomers measure the density of distant planets?
Researchers determine the density of an exoplanet by combining data from space-based observatories and ground-based telescopes. NASA’s Transiting Exoplanet Survey Satellite (TESS) first detects the planet as it crosses in front of its host star. According to Dransfield, scientists then use Earth-based telescopes to measure the orbit and physical characteristics of the system. By calculating the planet’s mass and volume, astronomers can derive its density. While Jupiter is a gas giant with substantial mass, these super-puffs are significantly more porous, with Jupiter measuring up to 35 times denser than the newly discovered pair.
A light-year is a measure of distance, not time. It spans nearly 6 trillion miles (9.7 trillion kilometers), highlighting the extreme precision required to characterize planets located over a thousand light-years from Earth.
Why are super-puffs rare in the galaxy?
Super-puffs are considered exotic anomalies in the current catalog of nearly 6,300 confirmed exoplanets. Current astronomical models suggest these planets form in the disk of gas and dust surrounding a newborn star. Dransfield notes that these environments are rich in gas, which allows the planet to accumulate a massive, fluffy atmosphere. Over time, the planet sheds much of this material, stripping down to its current, low-density state. With fewer than 40 confirmed super-puffs identified to date, these systems represent a small fraction of known worlds.
What do these planets reveal about the history of our solar system?
Studying rare systems allows astronomers to stress-test existing theories of planetary formation. By observing planets that exist at the extreme ends of the density spectrum, researchers can better understand the variables that determine whether a planet becomes a dense rock or a cloud-like giant. According to Dransfield, the goal is to add pieces to the complex puzzle of how planetary systems emerge from stellar nurseries. This comparative approach helps refine models that explain why our own solar system evolved with a specific arrangement of rocky inner planets and gas-heavy outer worlds.
Frequently Asked Questions
What is a super-puff planet?
A super-puff is an exoplanet with a very large radius but an extremely low mass, resulting in a density lower than that of cotton candy.
How many exoplanets have been discovered?
NASA has confirmed nearly 6,300 worlds outside our solar system to date.
Where are these new super-puffs located?
They orbit a star in the southern constellation Volans, also known as the flying fish, located 1,110 light-years from Earth.
If you want to track the latest exoplanet discoveries in real-time, visit the NASA Exoplanet Archive for updated counts and interactive data visualizations.
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