Artist’s concept of a previously proposed possible planet, HD 26965 b – is often compared to the fictional “Vulcan” in the Star Trek universe. Credit: JPL-Caltech
New research refutes the existence of Vulcan, a planet thought to orbit 40 Eridani A, attributing the detected signals to the surface activity of the star.
A planet thought to orbit the star 40 Eridani A — host to Mr. Spock’s fictional planet Vulcan in the “Star Trek” universe — is actually some kind of astronomical illusion caused by the pulsations and vibrations of the star itself. This is according to a new study published in Astronomical Magazine.
Initial excitement and later doubts
The potential discovery of a planet orbiting a star made famous by Star Trek drew excitement and much attention when it was announced in 2018. Just five years later, the planet appeared to be on shaky ground when other researchers asked whether was there at all. Now, precise measurements using a NASA– The NSF instrument, installed a few years ago on top of Kitt Peak in Arizona, seems to have returned the planet Vulcan even more definitively to the realm of science fiction.
Methods of detecting exoplanets
Two methods for discovering exoplanets—planets orbiting other stars—dominate all others in the ongoing search for strange new worlds. The transit method, looking at the slight dip in starlight as a planet passes the face of its star, is responsible for the vast majority of discoveries. But the “radial velocity” method has also racked up a healthy share of exoplanets discoveries. This method is especially important for systems with planets that, from Earth’s perspective, do not cross the faces of their stars. By tracking subtle changes in starlight, scientists can measure “wobbles” in the star itself, as the gravity of an orbiting planet pulls it in one direction, then another. For very massive planets, the radial velocity signal mostly leads to ambiguous planet detections. But non-massive planets can be problematic.
Questioning the existence of the Volcano
Even the scientists who made the original and likely discovery of the planet HD 26965 b – almost immediately compared to the fictional Vulcan – warned that it could turn out to be erratic stellar jitters masquerading as planets. 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, using high-precision radial velocity measurements not yet available in 2018, confirms that caution about the potential discovery was justified.
The NEID instrument clarifies doubts
The 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 oscillating motions. In this case, analyzing the planet’s supposed signal at different wavelengths of light, emitted from different levels of the star’s outer layer, or photosphere, revealed significant differences between the individual wavelength measurements – their Doppler shifts – and the total signal when all were combined. . That means, in all likelihood, the planet’s signal is really the vibration of something on the star’s surface that coincides with a 42-day rotation—perhaps the flipping of hotter and cooler layers beneath the star’s surface, called convection, combined with stellar surface features such as spots and “plages”, which are bright and active regions. Both can change the radial velocity signals of a star.
Potential for future breakthroughs
While the new discovery, at least for now, robs the star 40 Eridani A of its potential planet Vulcan, the news isn’t all bad. Demonstrating such fine-tuned radial velocity measurements holds the promise of making sharper observational distinctions between actual planets and the wobbles and crunches on the surfaces of distant stars.
Even the destruction of Vulcan is 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 employs an artificial. black hole to wipe out Spock’s home world.
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, “Death of Vulcan: NEID reveals candidate planet orbiting HD 26965 is stellar activity”, in Astronomical Magazine in May 2024 (Note: HD 26965 is an alternate name for the star, 40 Eridani A.)
Reference: “The Death of Vulcan: NEID Reveals Planet Candidate Orbiting HD 26965 Is Stellar Activity*” by Abigail Burrows, Samuel Halverson, Jared C. Siegel, Christian Gilbertson, Jacob Luhn, Jennifer Burt, Chad F. Bender, Arpitay , Ryan C. Terrien, Selma Vangstein, Suvrath Mahadevan, Jason T. Wright, Paul Robertson, Eric B. Ford, Gumundur Stefánsson, Joe P. Ninan, Cullen H. Blake, Michael W. McElwain, Christian Schwab, and Jinglin Zhao, 26 April 2024, Astronomical Magazine.
DOI: 10.3847/1538-3881/ad34d5
