South African researchers discover new, puffy exoplanet

Kelt-11b is a new exoplanet discovered by researchers in South Africa, collaborating with others from around the world. The discovery further solidifies South Africa’s reputation as a global leader in astronomy.

Kelt-11b
An artist’s impression of Kelt-11b, the newly discovered exoplanet, orbiting its host star, Kelt-11. (Image: Walter Benjamin, SAAO)

Compiled by Priya Pitamber

A new exoplanet, described as “puffed up”, “bloated”, and “having the density of Styrofoam” has been discovered by researchers at the South African Astronomical Observatory (SAAO), working together with others from around the world.

An exoplanet, or extrasolar planet, is a planet that orbits a star outside our solar system.

The newly discovered exoplanet, named Kelt-11b, is orbiting a star 320 light years away and shares some similarities with Jupiter and Saturn because it is also a gas giant. But there are differences too.

“The new exoplanet orbits its host star — called Kelt-11 — so closely that it completes an orbit in less than five days,” said the SAAO. “Kelt-11b has only a fifth of Jupiter’s mass, but is 40% larger in radius. This means that this new bloated planet has about the same density as Styrofoam.”

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The SAAO’s Dr Rudi Kuhn said it was an exciting discovery. “The planet Kelt-11b orbits one of the brightest stars known to host an exoplanet and is one of the most inflated planets ever discovered.”

This would enable researchers to make detailed observations of the atmospheric composition of the exoplanet using much larger telescopes such as the Southern African Large Telescope (SALT), Kuhn said.

“This will help us understand how these giant planets are formed, why they have such small orbits as well as what might happen to them in the future.”

How it works

Two small robotic telescopes are part of the Kelt (Kilodegree Extremely Little Telescope) with Kelt-North in Arizona in the US, and Kelt-South in Sutherland, South Africa. Kuhn helped with the construction of Kelt-South.

“The exoplanet was first discovered with the Kelt-South telescope and thereafter monitored by many telescopes around the world operated by researchers at universities as well as telescopes operated by amateur astronomers,” said the organisation.

What the researchers know

According to research findings published in The Astronomical Journal:

  • Kelt-11 is the brightest known transiting exoplanet host in the southern hemisphere;
  • It has a large atmospheric scale height, 2,763km, and;
  • Because of those characteristics, it could become the benchmark of the study of such exoplanets.

Source: SAAO

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