Research shows that the planet is actually an astronomical illusion caused by stellar activity

A planet thought to orbit the star 40 Eridani A — host to Mr. Spock’s fictional home planet, Vulcan, in the “Star Trek” universe — is actually some kind of astronomical illusion caused by its pulses and vibrations from the star itself, a new planet. study shows.

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

The possible detection of a planet around a star that made Star Trek famous attracted excitement and a lot of attention when it was announced in 2018. Just five years later, the planet seemed to be on shaky ground as other researchers wondered if it was even there. . Now precision measurements using a NASA-NSF instrument, installed a few years ago atop Kitt Peak in Arizona, appear to return the planet Vulcan even more definitively to the realm of science fiction.

Two methods of detecting exoplanets – planets orbiting other stars – dominate all others in the ongoing search for strange new worlds. The transit method, which looks for the small dip in starlight when a planet crosses the side of its star, is responsible for the vast majority of detections. But the ‘radial velocity’ method has also produced its fair share of exoplanet discoveries.

This method is especially important for systems with planets that, from Earth’s point of view, do not cross the planes of their stars. By tracking subtle shifts in starlight, scientists can measure “wobbles” in the star itself, as the gravity of an orbiting planet pulls it one way, then another. For very large planets, the radial velocity signal usually leads to unambiguous planet detections. But not so large planets can be problematic.

Even the scientists who made the original possible detection of planet HD 26965 b (almost immediately compared to the fictional Vulcan) warned that it could be messy stellar jitters masquerading as a planet. They reported evidence of a “super-Earth” – bigger than Earth, smaller than Neptune – in a 42-day orbit around a Sun-like star about 16 light-years away. The new analysis, using high-precision radial velocity measurements that were not available in 2018, confirms that caution regarding the possible discovery was warranted.

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

That means, in all likelihood, that the planet signal is actually the flickering of something on the star’s surface that coincides with a 42-day rotation – perhaps the swirling of hotter and cooler layers beneath the star’s surface, called convection. combined with the surface of the star. features such as spots and ‘plages’, which are bright, active areas. Both can change a star’s radial velocity signals.

Although the new find, at least for now, deprives star 40 Eridani A of its possible planet Vulcan, the news isn’t all bad. The demonstration of such finely tuned radial velocity measurements holds the promise of making sharper observational distinctions between actual planets and the vibrations and vibrations on surfaces of distant stars.

Even Vulcan’s destruction is foreseen 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 destroy Spock’s homeworld.