The study reveals that the planet is actually an astronomical illusion caused by stellar activity

The planet thought to be orbiting the star 40 Eridani A—home to Mr. Spock’s fictional home planet, Vulcan, in the “Star Trek” universe—is really a kind of astronomical illusion caused by the pulsations and tremors of the star itself, a new study shows.

A scientific team led by Dartmouth College astronomer Abigail Burrows, formerly of NASA’s Jet Propulsion Laboratory, published a paper describing the new result titled “Vulcan’s Death: NEID Reveals Planet Candidate Orbiting HD 26965 Is Stellar Activity” in Astronomical magazine. (Note: HD 26965 is an alternate designation for the star 40 Eridani A.)

The possible detection of a planet orbiting the star made famous by Star Trek caused excitement and a lot of attention when it was announced in 2018. Just five years later, the planet appeared to be on shaky ground when other researchers questioned whether it was even there. It seems that precise measurements using the NASA-NSF instrument, installed a few years ago on top of Kitt Peak in Arizona, have definitively returned the planet Vulcan to the realm of science fiction.

Two methods for discovering exoplanets—planets orbiting other stars—dominate all others in the ongoing search for unusual new worlds. The transit method, observing the tiny dip in starlight as a planet crosses the face of its star, is responsible for the vast majority of detections. But the “radial velocity” method has also garnered a healthy share of exoplanet discoveries.

This method is especially important for systems with planets that, from Earth’s point of view, do not intersect the faces of their stars. By tracking subtle shifts in starlight, scientists can measure “wobbles” in the star itself, as the gravity of orbiting planets pulls it to one side and then the other. For very large planets, the radial velocity signal generally leads to unequivocal planet detection. But not so big planets can be problematic.

Even the scientists who made the original, possible detection of the planet HD 26965 b—almost immediately compared to the fictional Vulcan—warned that it could turn out to be a messy stellar wobble masquerading as a planet. They reported evidence of a “super-Earth” — larger than Earth, smaller than Neptune — in a 42-day orbit around a sun-like star about 16 light-years away. The new analysis, which uses high-precision radial velocity measurements not yet available in 2018, confirms that caution about the potential discovery was justified.

Bad news for “Star Trek” fans comes from an instrument known as NEID, a recent addition to the telescope complex at Kitt Peak National Observatory. NEID, like other radial velocity instruments, relies on the Doppler effect: shifts in a star’s light spectrum that reveal its wobbly motions. In this case, analyzing the planet’s supposed signal at different wavelengths of light, emitted from different levels of the star’s outer shell (photosphere), revealed significant differences between the individual measurements of the wavelengths – their Doppler shifts – and the total signal when they were all combined.

This likely means that the planet’s signal is actually a flickering of something on the star’s surface that coincides with the 42-day rotation—perhaps the swirling of warmer and cooler layers below the star’s surface, called convection, combined with stellar surface features such as spots and “streaks.” , which are bright, active regions. Both can change the star’s radial velocity signals.

Although the new discovery deprives the star 40 Eridani A of its possible Vulcan planet, at least for now, the news isn’t all bad. Demonstration of such fine-tuned radial velocity measurements promises to make sharper observational distinctions between real planets and the jitters and rattles on the surfaces of distant stars.

Even the destruction of Vulcan was predicted in the “Star Trek” universe. Vulcan was first identified as Spock’s home planet in the original 1960s television series. But in the 2009 film, “Star Trek,” a Romulan villain named Nero uses an artificial black hole to blow up Spock’s homeworld.