The mystery of the swollen planet in the constellation Virgo.

(NLĐO) - The planet WASP-107b once puzzled scientists because it existed in a state resembling a ball of cotton candy.

WASP-107b is the name of one of the planets in the WASP-107 star system, located 212 light-years from Earth and in the constellation Virgo.

Scientists have given it a number of quirky names, such as "cotton candy planet" or "swollen planet".

Cotton candy planet WASP-107b - Graphic image: LUCA SCHOOL OF ARTS/NASA/ESA

The reason WASP-107b has these strange nicknames is because it looks like it's made of cotton.

According to NASA's exoplanet database, studies show that this strange world has a density of only about 0.19 - 0.202 g/cm3, while Earth's density is 5.51 g/cm3.

WASP-107b has a radius only slightly smaller than Jupiter's – 0.94 times Jupiter's radius. However, it is only about 30 times more massive than Earth. Jupiter – despite being a gas planet with a lower density than rocky planets – is still 318 times more massive than Earth.

Previous planetary formation models could not explain how such a large yet extremely light planet could have come into existence.

A research team led by physicist David K. Sing from Johns Hopkins University (USA) has solved this mystery in a study published in the scientific journal Nature.

Based on the radius, mass, age, and assumed internal temperature, they believe that WASP-107b has a very small rocky core surrounded by a large mass of hydrogen and helium.

But it's hard to understand how such a small core could absorb so much gas. And if the core were large, as the planet cooled, its atmosphere should have shrunk.

Combining observations from James Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) and Hubble's Wide-Field Camera 3 (WFC3), two of the most powerful space telescopes currently available, they measured the concentrations of countless particles in the atmosphere of WASP-107b.

These molecules include water vapor, methane, carbon dioxide, carbon monoxide, sulfur dioxide, and ammonia.

Both Hubble and James Webb spectra revealed a surprising lack of methane in WASP-107b's atmosphere: one-thousandth of the expected amount based on its temperature of 500 degrees Celsius.

There's only one explanation: Despite having a surface temperature that's "cool" compared to other "hot Jupiter" planets on record, this cotton candy planet possesses a very hot core, because methane is unstable at high temperatures.

This internal heat may be due to tidal heating caused by its elliptical orbit. Gravity changes as the planet moves farther and closer to its parent star, stretching the planet and causing this.

After determining that the planet had enough internal heat to completely churn its atmosphere, researchers realized that spectroscopy could also provide a new method for estimating the size of the core.

The results show that the planet's core is twice as large as initially expected. The larger, consistently hot core is the reason the planet has such a thick gaseous crust and maintains its cotton candy-like consistency over time.

In other words, it's a hotter version of Neptune than Jupiter.

Source: https://nld.com.vn/bi-an-hanh-tinh-sung-hup-giua-chom-sao-xu-nu-196240521081817059.htm