by The exoplanet covered in so many volcanoes that its molten surface is streaked with fiery red discovered in the orbit of a star 66 light year from the Earth.
That sentence might ring bells for Star Wars fans, as Obi-Wan Kenobi fought and defeated Anakin Skywalker on the lava planet of Mustafar. But believe it or not, even that world has nothing on the newly discovered TOI-6713.01. Despite the need for a catchier name, the vital statistics put it in the realm of the extraordinary.
“This is what I would describe as a terrestrial planet Io on steroids,” Stephen Kane of the University of California, Riverside, pointed out Jupiter‘ volcanic moon, in a statement. Io is the largest volcanic body in our system Solar systemwith every inch of its surface covered in lava plains – but it could be considered tame compared to TOI-6713.01.
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The exoplanet, which is a “Super Earth” 30% larger than our own World, orbits its star HD 104067 every 2.2 days for a distance of 4.57 million kilometers (2.8 million miles). It is accompanied by two other worlds, one on another rocky planet that sits about 15.8 million kilometers (9.8 miles) from the star and the other gas giant a planet located about 40 million kilometers (24.8 million miles) from that central anchor. Let’s compare this image to our own solar system. The planet closest to us Sun yes mercury, which has an elliptical, or non-circular, orbit that ranges from 46 million to 69.82 million kilometers (28.5 million to 43.3 million miles) from the sun. Yes, that means the entire planetary system orbiting HD 104067 could fit inside the orbit of Mercury.
Like Mercury, TOI-6713.01’s orbit is highly elliptical. In the case of Mercury, the planet is far enough from our sun that it doesn’t really feel any impact from the warming of this barren season; TOI-6713.01, however, almost within touching distance of its star. It is also drawn in an elliptical orbit because of the gravity of its neighboring planets, forcing TOI-6713.01 to receive gravitational tides, which stretch and twist the planet’s molten malleable interior as the planet regularly orbits closer to its star, then farther away. Kane refers to this as a “storm tide.”
The tidal forces of the storm, in turn, heat the interior of TOI-6713.01, providing it with enough energy to erupt its entire surface with volcanoes.
“It’s been forced into a situation where it’s constantly exploding with volcanoes,” Kane said. This results in a situation where the planet’s molten surface radiates with temperatures of up to 2,600 kelvin (2,327 degrees Celsius, or 4,220 degrees Fahrenheit). To put such a temperature into perspective, that’s hotter than some low-mass stars!
“This teaches us the extremes of how much energy can be pumped into a terrestrial planet, and the consequences of that,” Kane said. “Although we know that stars adding to the heat of the planet, tidal energy is the vast majority of energy here and cannot be ignored.”
In 2011 HARPS (High Precision Radial Velocity Planet Finder), a planet-finding instrument at the La Silla Observatory in Chile, discovered the giant planet HD 104067, which is one-fifth the mass of Jupiter. HARPS measures the “tilt” of a star with respect to its rotational axis, as the star rotates around a center of mass it shares with its planets. A second planet in the system was also found by HARPS, along with its counterpart HIRES (High Resolution Echelle Spectrometer), at the WM Keck Observatory in Hawaii. The third planet – TOI-6713.01 – was not seen until Kane came to look at the star made by NASA TESS (Transiting Exoplanet Survey Satellite).
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“It was one of those moments of discovery where you think, ‘wow, it’s amazing that this can actually exist,'” Kane said.
Discovering it by the transit method of exoplanet hunting, in which the planet passes in front of its star from our perspective in the cosmos and blocks some of the light coming from its star, Kane and his team already know the diameter of TOI-6713.01 . That’s thanks to calculations of how much starlight the planet blocked during transit. The next step is to measure the planet’s mass by measuring the “wobble” of its star using HARPS and HIRES. Once its mass and radius are known, TOI-6713.01’s density can be calculated, and this will allow Kane’s team to determine how much material might be available to erupt from many (many) volcanoes TOI-6713.01.
The results were published on 25 April i The Astronomical Journal.
