Astronomers find ultra-hot planet that has iron in its atmosphere, orbits star in less than 2 days

Astronomers have discovered a new ultra-hot Jupiter-like exoplanet in deep space that has an interesting characteristic: its atmosphere contains iron.

Known as TOI-1518b, this planet was observed when NASA’s Transiting Exoplanet Survey Satellite (TESS) was observing the star TOI-1518.

The new planet has a radius of approximately 1.875 Jupiter and its mass is just over twice that of Jupiter, according to researchers at Yale University, who made the observation.

‘Prompted by recent detections of atomic and ionized species in ultra-hot Jupiter atmospheres, we conduct an atmospheric cross-correlation analysis,’ the researchers wrote in the study.

‘We detect neutral iron … adding another object to the small sample of highly irradiated gas-giant planets with [iron] detections in transmission,’ the authors wrote in the study.

It has a radius of approximately 1.875 Jupiter (pictured) and its mass is just over twice that of the largest planet in the solar system

In addition to having iron in its atmosphere, the ‘ultra-hot’ TOI-1518b has an equilibrium temperature of 2,492 Kelvin and a dayside temperature of 3,237 Kelvin.

This makes it ‘a promising candidate for future emission spectroscopy to probe for a thermal inversion,’ the study’s authors wrote.

Thermal inversion occurs when air gets colder with altitude: in effect, the surface of a planet cools as it turns to night and the cold air gets closer to the ground. 

For comparison, its star has a temperature of 7,300 Kelvin and the surface temperature of the sun is 5,778 Kelvin. 

Planet TOI-1518b also orbits its star in less than two days at a distance of approximately 0.04 astronomical units or 3,718,232 miles.  

It also has a misaligned orbit, which is likely due to the fact that other gas giants that orbit stars this close are usually off kilter.

The research paper was published last month on the arXiv pre-print repository.

The planet was discovered while NASA’s Transiting Exoplanet Survey Satellite was observing the star TOI-1518

NASA’s TESS launched in April 2018 at a cost of $200 million and is the successor to the Kepler Space Telescope. 

Since its launch, it has identified 154 planets, with an additional 4,471 candidates, according to NASA’s website. 

It completed its primary mission on July 4, 2020 and is now in an extended mission. 

WHAT IS THE TESS SPACECRAFT?

NASA’s new ‘planet hunter,’ set to be Kepler’s successor, is equipped with four cameras that will allow it to view 85 per cent of the entire sky, as it searches exoplanets orbiting stars less than 300 light-years away.

By studying objects much brighter than the Kepler targets, it’s hoped TESS could uncover new clues on the possibility of life elsewhere in the universe.

Its four wide-field cameras will view the sky in 26 segments, each of which it will observe one by one.

In its first year of operation, it will map the 13 sectors that make up the southern sky.

Then, the following year, it will scour the northern sectors.

‘We learned from Kepler that there are more planets than stars in our sky, and now TESS will open our eyes to the variety of planets around some of the closest stars,’ said Paul Hertz, Astrophysics Division director at NASA’s Headquarters. 

‘TESS will cast a wider net than ever before for enigmatic worlds whose properties can be probed by NASA’s upcoming James Webb Space Telescope and other missions.’

Tess is 5 feet (1.5 meters) wide and is shorter than most adults.

The observatory is 4 feet across (1.2 meters), not counting the solar wings, which are folded for launch, and weighs just 800 pounds (362 kilograms). 

NASA says it’s somewhere between the size of a refrigerator and a stacked washer and dryer. 

Tess will aim for a unique elongated orbit that passes within 45,000 miles of Earth on one end and as far away as the orbit of the moon on the other end.

It will take Tess two weeks to circle Earth.