Current DateNovember 24, 2021

Giant planet discovered circling a star in an extremely tight orbit

A new planet, TOI-2109b, has been identified circling a star roughly 855 light-years away from Earth, according to recent discoveries. This planet’s orbit is so short that it completes one revolution around its star in just 16 hours. Researchers predict it to collide with its star within a few million years after its discovery.

Exoplanets may be discovered via the transit technique.

This new planet was discovered using the transit technique. This approach is used to identify the existence of an object circling about a star by monitoring fluctuations in its brightness: when an object passes between the observer and the star, a minor decrease in the luminosity measured from the star is observed. It is this change in luminosity that the scientists at Tess discovered, which prompted them to alert the scientific community about it, which eventually allowed them to establish the existence of a planet circling around TOI-2109, owing to further studies carried out by ground-based telescopes.

The period of revolution (the amount of time it takes for a star to complete a rotation around the center of its orbit) of this planet was determined by measuring the frequency at which the luminosity measured by the telescope varies. The scientists were surprised to discover that it would complete a revolution around its star in only 16 hours.

The team of experts was able to determine the mass and size of TOI-2109busing data obtained at different optical and infrared wavelengths. TOI-2109b is five times more massive and 35 percent bigger than Jupiter, according to the findings. The planet would also orbit at a very close distance to its star, around 2.5 million kilometers: it would have the shortest orbit of any of the gas giants that have been observed to date. To put that in perspective, Mercury, the planet in the Solar System closest to the Sun, is nearly 60 million kilometers away.

In part due to its incredibly tight orbit, the planet is in synchronous rotation with its star: it constantly shows the same face to the star, thereby generating a permanent day side and a perpetual night side. Researchers estimate that the surface temperature on the day side of this exoplanet is 3,500 degrees Celsius, nearly as hot as a small star, making it the second hottest planet yet discovered. The planet is labeled an “ultra-hot Jupiter,” as opposed to “hot Jupiter,” which are normally further away from their star and consequently cooler.

The astronomers believe that the planet is bound to collide with its star within a few million years due to its exceedingly short orbit. In the words of Ian Wong, the study’s main author, “In one or two years, if we are luckywe may be able to detect how the planet moves closer to its star.”

The researchers hope to examine TOI-2109b in the near future with more powerful equipment, in particular owing to the Hubble and James-Webb space telescopes, in order to shed light on the process that “hot Jupiters” go through as they fall towards their star. Further investigations may also help us comprehend how a planet with the mass of TOI-2109b is able to travel such a small distance in its orbit.

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