If you thought life on Earth during a pandemic was tough, imagine living on a lava planet, battered by violent weather, with rocks literally raining and wind howling thousands of miles per hour.
This is the portrait painted in a new study by scientists from McGill University, York University and the Indian Institute of Science Education and research in Calcutta published Tuesday in the Royal Astronomical Society Monthly Notices.
The researchers described the conditions on this planet, called K2-141b, which is located about 210 light years from Earth. It orbits extremely close to its star, which is only slightly smaller than our sun.
This “lava” planet completes one revolution in about six or seven hours, almost skimming the surface of the star as it darted through space.
In contrast, Mercury, the closest planet to the sun in our solar system, takes 87 days to orbit the sun.
“Nearly half of the planet is molten magma,” said study lead author Tue Giang Nguyen, a doctoral student at York University in Toronto. “The atmosphere created by the vaporized rocks spreads across the planet.”
That vaporized silicon dioxide, or quartz, forms clouds and rains or snows on the molten surface below, he said.
A strange planet
To discover an exoplanet – a planet that orbits a star other than the Sun – astronomers measure the difference in light emitted by a star when a planet is behind it in its orbit compared to the one in front of it, Nguyen explained. When viewed through a telescope on Earth, the star appears dimmer when the planet is in front of it, slightly obscuring the view from Earth.
Scientists have discovered thousands of worlds beyond our solar system using this method. Few of them, however, have surfaces so fused that they cause such dramatic swings over time and in the structure of a planet. In the available literature, Nguyen saw that astronomers only observed a handful of lava planets.
Exoplanet K2-141b has winds that come in at around 3,100 miles per hour (5,000 kilometers per hour) and its magma ocean is estimated to be about 86 miles (140 kilometers) deep, according to Nguyen’s calculations.
Extraordinary winds dominate one side of the planet but are totally absent on the other.
The positive side of the K2-141b is scorching hot, with temperatures likely to be around 5,400 degrees Fahrenheit, or 3,000 degrees Celsius. That warm side has an atmosphere made of silicon dioxide, more commonly known as quartz.
Because K2-141b orbits so close in its star’s brilliant glow, about two-thirds of the world is illuminated at any given time. One third is dark, which makes for a freezing planet with temperatures of minus 392 degrees Fahrenheit, or minus 200 degrees Celsius.
That two-thirds light / one-third dark split is unusual compared to planets in our solar system, such as Earth and Jupiter, where half of the planet would be illuminated by the sun at any given time.
“It’s a planet that doesn’t make much sense. There’s nothing like it in our solar system, ”said study co-author Nicolas Cowan, an associate professor in the departments of physics and earth and planet sciences at McGill University in Montreal.
Lava planets are quite rare, Cowan noted: only one in 1,000 stars would be able to host one. But given the enormity of the cosmos, there could be billions of lava worlds out there.
Studying such an exotic planet could pay off, helping scientists understand a version of the conditions that existed on Earth during its formation, when it too was covered in molten lava billions of years ago. Looking closely at the lava planet could provide answers as to how it originated – and the Earth – Cowan said.
“It’s a strange, bare, rocky core of what used to be a larger planet,” he said.
Look for another land
“Lava planets have certainly captured people’s imaginations, and they are a rare, but very real class of planets,” said Jonathan Fortney, professor of astronomy and astrophysics at the University of California, Santa Cruz, in an e -mail. “Unlike a planet like Earth, the material that makes up this planet’s atmosphere is literally the same materials that make up the crust.”
Fortney compared K2-141b, and similar lava planets, to Pluto, which is rich in nitrogen in the form of ice in its crust and gas in its atmosphere.
“Planets like this open up the prospect of using the atmosphere (which is increasingly easier to study) to learn about the composition of the crust, which is much more difficult to study,” he said via email.
Nguyen and Cowan both said they hope to continue studying the lava planet, which will soon be observable with next-generation devices from NASA’s James Webb Space Telescope, scheduled to launch next year.
The new space telescope will enable them to acquire high-resolution spectrographs of the planet and gain a closer understanding of the composition of its interior, ocean and atmosphere.
“This is an incremental step in trying to find Earth 2.0. This is an ending to space exploration, ”Nguyen said.