Mystery of the Puffy Planet in the Constellation of Virgo

(NLDO) - Planet WASP-107b once confused scientists because it existed in a state like a block 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 call it by many strange names like "cotton candy planet" or "puffy planet".

Cotton Candy Planet WASP-107b - Image courtesy of LUCA SCHOOL OF ART/NASA/ESA

The reason WASP-107b has such 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, compared to Earth's density of 5.51 g/cm3.

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

Previous planet formation models could not explain how such a large yet extremely light planet could have formed.

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 its radius, mass, age, and assumed interior temperature, they believe WASP-107b has a very small rocky core surrounded by a large mass of hydrogen and helium.

But it is difficult to understand how such a small core could have sucked in so much gas. If the core were large, then as the planet cooled, its atmosphere should have contracted.

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

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

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

There's only one explanation: Despite its very "cool" surface temperature compared to other known "hot Jupiter" planets, the cotton candy planet has a very hot core, because methane is unstable at high temperatures.

This internal heating may be due to tidal heating caused by its elliptical orbit. The gravitational pull changes as the planet moves closer to and farther away from its parent star, causing this.

After determining that the planet has enough heat inside to fully churn its atmosphere, the researchers realized that spectroscopy could also provide a new way to estimate the size of its core.

The results showed that the planet's core was twice as big as originally thought. The larger, hotter core is why the planet has such a thick gaseous envelope and has maintained its cotton candy state over time.

In other words, it is 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