Astronomers may have found water in the atmosphere of a scorching hot planet that is also one of the most metallic planets ever discovered, a discovery that could shed light on the planet’s formation, which remains a mystery.
Exoplanets, or “ExoplanetsThe object in question is HD 149026 b, also known asSmertriosSmertrius means “purveyor” or “provider” and is worshipped as the god of war in Gaelic tradition. Smertrius orbits a yellow subgiant star called HD 149026, about 247 light years from Earth.
The planet is about 4 million miles from its parent star, orbits it in less than three Earth days, and is about three-quarters the width of the Sun. JupiterSmertrius is classified as a “hot Saturn” and is named after A small gas planet in the solar system.
The fact that Smertrios is close to the star means Tidal Lock The star’s dayside always faces that way, and its temperature reaches up to 2,600 degrees Fahrenheit (1,420 degrees Celsius). The cooler nightside always faces space. But it’s Smertrios’ density and composition, which was discovered when it crossed, or “transited,” the star’s face in 2005, that make it truly strange.
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“Hot Saturn is”A hot gas giant.“Hot gas planets are exoplanets with a size of Jupiter “This planet is similar to an exoplanet or Saturn, but it orbits its host star extremely closely. Typically, these planets have orbital periods of less than 10 days, so a year on these planets could be less than a week,” Sayyed Ali Rafi, an astronomy researcher at the University of Tokyo and part of the team that contributed to the discovery, told Space.com. “This planet is particularly interesting because it is one of the most metal-rich and dense gas giants we know of so far.”
When astronomers like Ali Rafi use the word “metal,” they’re referring to elements heavier than hydrogen or helium. The James Webb Space Telescope (JWST) will observe Smertrius in 2023.Powerful space telescopes have found that the planet’s metallicity, or the ratio of metals to hydrogen, is much higher than most hot Saturns and larger hot Jupiters. Solar System The giants, Jupiter and Saturn.
Typically, the amount of metal in a gas giant is thought to be inversely proportional to its mass — that is, the larger the gas giant, the less metal it should contain. Smertrios bucks this trend. It also turns out the planet has an unusually large solid core, which is why it’s so dense.
“The composition of this planet does not seem to match current formation scenarios for hot gas giants and remains a mystery to this day,” Ali Rafi said. “This shows the importance of observing planetary atmospheres, as they can help reveal the formation history of planets through atmospheric properties such as metallicity and the ratio of carbon to oxygen.”
Which way does the wind blow in Smertrius?
To investigate Smertrius’ strange atmosphere and understand why the planet is “metallic,” Ali Rafi and his colleagues CARMENES SpectrometerObservation equipment installed at the Calal Alto Observatory in Spain.
Elements and chemical molecules absorb and emit light at characteristic wavelengths, and when a planet like Smertrios passes over the face of its star, elements in its atmosphere leave “fingerprints” in the filtered light. Starlight. CARMENES can read these fingerprints and tell astronomers what its atmosphere is made of.
CARMENES’ investigation of Smertrios has revealed traces of water vapour, which allows more precise constraining of the abundance of other materials. Elements in the planet’s atmosphere.
Ali Rafi explained that if we assume that elemental oxygen is more abundant than elemental carbon in the atmosphere of a hot gas giant like Smertrios, this means that the two most abundant “tracer” species that could explain the properties of its atmosphere are water and carbon monoxide.
“Therefore, if we can constrain the abundance of both molecules, we can constrain the ratio of carbon to oxygen in the atmosphere, which is very important because it could act as a kind of tracer characteristic for the formation and evolutionary history of gas giants like HD 149026 b,” Ali Rafi added. “Finding water in the atmosphere is the first step in such a characterization, and that’s why it’s important.”
But that wasn’t all the team discovered about Smertrius: the hot Saturn planet gave the researchers quite a surprise.
Typically, tidally locked hot gas giants have such a large temperature difference between their hot dayside and cooler nightside that they generate extremely fast atmospheric winds that can reach speeds of up to 5,000 miles per hour (8,046 km/h).
On most other planets, winds move from hotter to cooler regions, so these winds usually blow from the day side of the planet to the night side. But Smertrius’ winds seem to blow in the opposite direction — from the night side of the planet to the day side.
“Since we observe the planet as it passes, this means that the winds blowing on the night side will be blowing towards the observer, and the absorption spectrum of the planet will be Blueshift“But what we found is that it is redshifted, which was a big surprise for us. There are several possible scenarios that could explain the fact that there might actually be a wind blowing from the nightside to the dayside,” Ali Rafi explained.
One possibility is that these winds originate in the deep atmospheric layers and Redshift spectrumThe researchers added that Smertrius’ orbit may not be circular, but flattened or “eccentric,” which could lead to changes in the spectrum that the team had not considered.
“Further observations are needed to confirm any of these scenarios or to see if there are other options,” Ali Rafi added.
Astronomers plan to continue studying the strangely hot Saturn to confirm their detection of water vapor.
“Further transit observational data from this planet are needed to verify our findings. We are currently working to confirm evidence of water and look for other atmospheric substances, as well as constrain their abundance and better estimate metallicity and carbon-oxygen ratios,” Ali Rafi concluded. “Hopefully, this will help shed light on the formation and evolutionary history of Smertrios!”
A peer-reviewed version of the team’s research is publicly available on a research repository site. arXiv.
