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

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

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

The possible detection of a planet orbiting the star made famous by Star Trek generated excitement and a lot of attention when it was announced in 2018. Just five years later, the planet appeared to be on shaky ground as other researchers questioned whether it was even there. . Now, precise measurements by a NASA-NSF instrument installed a few years ago atop Kitt Peak in Arizona seem to have returned 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 vast majority of detections are accounted for by the transit method, which tracks the slight dip in starlight as a planet crosses the face of its star. But the “radial velocity” method has also garnered a healthy share of exoplanet discoveries.

This method is especially important for systems with planets that do not intersect the faces of their stars from Earth’s perspective. By tracking subtle shifts in starlight, scientists can measure “wobbles” in the star itself, as the orbiting planet’s gravity pulls it in one direction, then another. For very large planets, the radial velocity signal usually leads to an unambiguous detection of the planets. But not very large 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 chaotic stellar jitter 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. A new analysis using 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 the 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, analysis of the planet’s predicted signal at different wavelengths of light emitted from different levels of the star’s outer envelope (the photosphere) revealed significant differences between the individual wavelength measurements—their Doppler shifts—and the total signal when they were all combined. .

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

While the new find, at least for now, robs the star 40 Eridani A of its possible planet Vulcan, the news isn’t all bad. The demonstration of such fine-tuned radial velocity measurements offers the promise of sharper observational differences between real planets and the shakes and rattles of the surface of distant stars.

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