For the first time.. the James Webb telescope takes clear images of the planet “Little Neptune” | Science

The planet probably formed far from its star and then gradually moved inward to its current orbit, since the planet’s year is only 1.6 Earth days.

A “Little Neptune” planet is a type of extrasolar planet, sometimes called a gas dwarf or interstellar planet, that is much less massive than the masses of the planets Neptune and Uranus in our Solar System. On the other hand, the presence of an atmosphere of dense hydrogen and helium is similar to that of Neptune.

Small Neptune may have deep layers of ice or rock, liquid oceans of water, ammonia, a mixture of the two, or heavy vapor, a common but little-known type of planet in the galaxy.

Now, the US National Space Agency’s (NASA) James Webb Space Telescope has discovered a distant planet outside our solar system that reveals a very bright world with a steamy atmosphere, and notes. news Posted by NASA on its website on May 10, these images are so close to the mysterious planet that it was mostly obscured in previous observations.

Water vapor in the atmosphere

Although the planet, known as “GJ 1214 b,” is too hot to harbor oceans of liquid water, water in its gaseous state may be an important part of its atmosphere, says University of California, Irvine researcher Elisa Kimpton. Maryland and lead author of a new paper published in the journal Nature (Nature) “The planet is completely shrouded in some kind of mist or layer of clouds. And the atmosphere is completely hidden from us until the last observation.” And if the planet was indeed watery, it would be a “water world” that had large amounts of water material and glaciers when it formed.

To penetrate such a thick barrier, the research team used a new experimental approach. In addition to the standard observation process that relies on the light filtering of the host star in the planet’s atmosphere, they observed the planet “GJ1214b” throughout its entire orbit. Its star..

Miri camera

This observation demonstrates the power of the MERRY camera (a mid-infrared astronomical photographic camera) to capture wavelengths of light outside the region of the electromagnetic spectrum visible to the human eye. Using that, the research team was able to create a “heat map of the planet” that showed both day and night as it orbited the star. Both the planet’s composition (when its orbit took it just behind the star, and when it emerged on the other side) and its atmosphere revealed details.

“Getting a full orbit is critical to understanding how the planet distributes heat from day to night,” says Dr. Kimpton. “There is a lot of difference between day and night. The night side is cooler. In fact, the temperature changed from 279 to 165 degrees Celsius.

Such a large change is possible only in an atmosphere made up of heavier molecules like water or methane, Kimpton said, meaning that GJ1214b’s atmosphere is largely devoid of light hydrogen molecules when viewed through Merry’s camera. , which is key evidence for the planet’s history, structure, and its watery beginning, and continues, “It is not a primordial atmosphere. It does not reflect the composition of the host star that formed around it. Rather, it either lost a lot of hydrogen — if it started with a hydrogen-rich atmosphere — or was destroyed.” ” It was initially composed of heavier elements, ice and watery material.

Cooler than expected

Kimpton pointed out that while the planet is warm by human standards, it is much cooler than expected, and that its unusually bright atmosphere (surprising to researchers) reflects much of the light. The new observations could open the door to deeper knowledge of this type of unknown planet, rather than absorbing its parent star and increasing its temperature.

“For more than a decade, the only thing we knew about this planet was that its atmosphere was cloudy or hazy,” said exoplanet researcher Rob Zelm, who works with NASA’s Exoplanet Research Fellow Tiffany Kataria. The paper has very impressive implications for the Jet Propulsion Laboratory for more detailed climate descriptions and for looking at the detailed physics occurring in this planet’s atmosphere.”

Red Dwarf

The new work suggests that the planet may have formed far from its star, a type known as a red dwarf, and then gradually moved inward to its current orbit, where the planet’s year — one revolution around the star — takes only 1.6 Earth days, Kimpton says. “The simplest explanation is that if you find a very water-rich planet, it formed far away from the host star.”

In the future, more observations of GJ1214b and other minor Neptune-class planets will be needed to determine the formation dates, and while it seems logical for this planet to have a water-rich atmosphere, it is possible. Methane is the major component, and more detailed observations are needed to make detailed conclusions about how Little Neptune formed. “By observing such total planets, we hope to build a consistent story,” concludes Kimpton.