In a surprising turn of events, a study led by astronomer Abigail Burrows of Dartmouth College has revealed that the planet believed to orbit the star 40 Eridani A, famously known as Vulcan in the "Star Trek" universe, is nothing more than an astronomical illusion caused by the unpredictable behavior of the star itself. The findings, published in The Astronomical Journal, provide a more definitive conclusion, firmly placing the planet Vulcan back into the realm of science fiction.

The discovery of a potential planet orbiting the star 40 Eridani A had initially sparked excitement and captivated attention back in 2018. However, subsequent inquiries by other researchers raised doubts regarding its existence. Now, utilizing precision measurements obtained from a NASA-NSF instrument installed atop Kitt Peak in Arizona, the planet known as Vulcan seems to have been conclusively debunked as a mere product of stellar activity.

The study highlights the significance of two primary methods for detecting exoplanets, namely the transit method and the radial velocity method. While the transit method, observing the slight dip in starlight when a planet passes in front of its star, has led to the majority of exoplanet discoveries, the radial velocity method has also played a crucial role in identifying such celestial bodies.

The radial velocity method involves tracking subtle shifts in starlight caused by the gravitational pull exerted by an orbiting planet on its host star. However, it becomes more challenging to detect smaller planets through this method. Even the original scientists who reported the possible detection of planet HD 26965 b, often equated to Vulcan, expressed caution, suggesting the likelihood of stellar fluctuations mimicking a planet. They presented evidence of a "super-Earth" in a 42-day orbit around a star resembling our sun, located approximately 16 light-years away.

The present analysis, employing high-precision radial velocity measurements not available in 2018, affirms these suspicions, justifying the initial skepticism surrounding the supposed discovery.

Unfortunately for "Star Trek" enthusiasts, the disappointing news emerges from the NEID instrument at Kitt Peak National Observatory. NEID, similar to other radial velocity instruments, utilizes the Doppler effect to observe the shifts in starlight that reveal the star's motion. By studying the purported planet signal across various wavelengths of light emitted from different levels of the star's outer layer, significant disparities were observed between individual wavelength measurements and the overall combined signal.

These findings strongly suggest that the supposed planet signal is, in fact, the result of fluctuations occurring on the star's surface, such as convection and the presence of bright and active regions known as "plages." These phenomena can profoundly impact a star's radial velocity signals.

Although the demise of Vulcan in the "Star Trek" universe has been anticipated, the loss of its existence in astronomical terms is somewhat bittersweet. On a positive note, this breakthrough demonstrates the potential of highly precise radial velocity measurements in discerning between actual exoplanets and surface perturbations on distant stars. It opens up new possibilities for more accurate characterization of planetary systems.

It is worth noting that Vulcan was famously depicted as the home planet of Mr. Spock in the original "Star Trek" television series from the 1960s. However, in the 2009 film adaptation, a Romulan antagonist named Nero employs an artificial black hole to obliterate Vulcan.

The study, titled "The Death of Vulcan: NEID Reveals That the Planet Candidate Orbiting HD 26965 Is Stellar Activity," serves as a significant contribution to our understanding of exoplanet detection and underscores the necessity of robust observational techniques to distinguish real planets from astronomical illusions.

Reference:
Burrows, A., et al. (2024). The Death of Vulcan: NEID Reveals That the Planet Candidate Orbiting HD 26965 Is Stellar Activity. The Astronomical Journal. DOI: 10.3847/1538-3881/ad34d5