The presence of sulfur dioxide in the atmosphere of the exoplanet GJ 3470b, approximately 96 light-years from Earth, contradicts existing theories on planet formation.
The James Webb Space Telescope (JWST) discovered this finding, offering novel insights into the planet's past and distinctive features.
(Photo: AI-Generated / Austin Jay)
Surprising Find of Sulfur Dioxide
GJ 3470b goes around its star every three and a half days. It is a "hot Neptune" with a mass 13.9 times Earth's and a width 40% that of Jupiter. The planet goes over the star's poles in this highly inclined orbit, which goes against the usual ideas about how planets form.
In our solar system, planets usually form inside a disk of gas and dust lined up with a star's axis of motion. However, the 89-degree tilt of GJ 3470b's orbit points to a different past of formation.
Thomas Beatty, a researcher at the University of Wisconsin, Madison, expressed astonishment at the discovery of sulfur dioxide on a relatively small celestial body. He said they believed sulfur dioxide would not exist on such small planets.
The scientists are greatly excited by the serendipitous finding of this innovative compound in an unforeseen site.
The accidental finding of sulfur dioxide offers us a novel outlook on the mechanism of planetary creation.
The occurrence of sulfur dioxide in the atmosphere of GJ 3470b is a consequence of chemical reactions among its core elements. Because the planet is getting close to its star, ultraviolet light from the star breaks up molecules in the air.
When the sulfur atoms are freed, they join with oxygen to make sulfur dioxide. This swirling of chemicals shows that the atmosphere is active and is affected by the planet's proximity to its star.
New Meanings For Theories About How Planets Form
Finding sulfur dioxide in GJ 3470b's atmosphere is important for learning how planets form. According to our current models, gas giants start out far from their stars, where gas is more plentiful, and then move closer to their stars.
But GJ 3470b only moves 5.3 million kilometers away from its star, much closer than anyone thought. This close orbit, along with the strange makeup of its atmosphere, points to a different way it formed.
Researchers think GJ 3470b started as a hard planet close to its star before it got a thick atmosphere of hydrogen and helium. The Hubble Space Telescope previously observed that these lighter elements made up the majority of the atmosphere, supporting this notion. The JWST's sulfur dioxide finding complicates matters even more. It demonstrates that a multitude of chemical reactions formed the planet.
Beatty and his group used transmission spectroscopy to detect sulfur dioxide in the air close to GJ 3470b. As the planet revolves around its star, molecules in its atmosphere absorb light from the star.
This creates dark absorption lines in the star's spectrum, which helps us determine what's in the air. The Earth's hazy atmosphere made it hard for the JWST to find sulfur dioxide, but it could find carbon dioxide, methane, and water vapor.
As far as we know, GJ 3470b is the lightest and coldest world known to have sulfur dioxide in its atmosphere. So far, only much hotter exoplanets have been found to contain sulfur dioxide, which suggests that it can form in a wider range of conditions than was thought before.
Furthermore, radon from the star of GJ 3470b is removing its atmosphere, causing the planet to lose mass over time. Astronomers estimate that the planet has lost almost 40% of its mass. The planet's tilted orbit and peculiar atmosphere and this mass loss provide us with important information about its formation and evolution over time.
Beatty presented his discoveries during the 244th gathering of the American Astronomical Society. He underlined that "understanding planetary formation requires sulfur dioxide."
The study emphasizes the need to understand the chemical processes that create planet atmospheres. It will be published soon in the Astrophysical Journal Letters. By examining the features and behavior of GJ 3470b, scientists hope to learn more about the evolution and progress of comparable planets in other regions of the galaxy.
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