A planet beyond the solar system that has been compared to Spock’s homeworld of Vulcan in the Star Trek franchise may have been nothing more than an illusion caused by a jittery star.
The extrasolar planet or “exoplanet” (term for a planet outside our solar system) has been proposed to orbit a star called 40 Eridani A or “Keid”, which is part of a triple star system located approximately 16.3 light years from Earth. . In Star Trek, this star is also home to the planet Vulcan. First announced in 2018, the planet caused a stir thanks to its similarities to Spock’s fictional home planet.
A team of scientists led by Dartmouth College astronomer Abigail Burrows now believes that the “wobble” of this planet’s parent star is not the result of an orbiting world tugging on it at all. Burrows and his colleagues discovered, using a NASA instrument called NEID, located at the Kitt Peak National Observatory, that the origin of this oscillation is actually Keid’s “pulses and tremors.” himself.
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The fictionalized version of Vulcan was first introduced during Gene Roddenberry’s seminal original Star Trek series, mentioned in the unaired 1965 pilot episode “The Cage”. In the JJ Abrams-directed Star Trek reboot in 2009, Vulcan was destroyed by a time-traveling enemy of Kirk, Spock, and the rest of the Enterprise crew.
By erasing the actual Vulcan, officially designated HD 26965 b, this new research shows that sometimes life imitates art.
Sorry Keid, you’re alone…
There are several ways to detect exoplanets orbiting distant stars, but the two most effective techniques are the transit method and the radial velocity method. Both of these techniques take into account the effect of an orbiting planet on its star.
The transit method, used with great success by NASA’s Transiting Exoplanet Survey Satellite (TESS), measures the tiny dips in light caused by a planet as it crosses the face of its parent star.
Although the transit method is by far the more effective of these two methods for detecting exoplanets, the radial velocity method is useful for spotting exoplanets that do not pass between the face of their star and our observation point. in the solar system.
The radial velocity method uses tiny changes in a star’s light when an orbiting planet tugs on it gravitationally. When a star moves away from Earth, the wavelength of the light it emits stretches, causing it to move toward the “red end” of the electromagnetic spectrum, a phenomenon called “redshift.” The opposite occurs when the star is pulled toward Earth, the wavelengths of the light compress and the light is “blue-shifted” toward the “blue end” of the electromagnetic spectrum.
This is analogous to the Doppler effect, which impacts sound waves on Earth. When an ambulance rushes towards us, the sound waves from its siren are compressed, making them higher pitched. As the ambulance moves away, the sound waves are spaced further apart and the siren becomes louder.
The radial velocity method is best for detecting particularly massive planets, because these exert a greater gravitational pull on their stars and thus generate a more pronounced shift of starlight coming from that stellar body. However, it is less robust in detecting planets with masses less than that of Jupiter, the most massive planet in the solar system.
When HD 26965 was first potentially detected using the radial velocity method, its mass was estimated to be about 8 times that of Earth but less than that of Neptune, making it a so-called “planet”. super-Earth. False-Vulcan was suspected to orbit its parent star at about 22% of the distance between Earth and the sun, completing a year in about 42 Earth days.
Yet even the scientists who discovered this planet warned that it could be a detection error caused by Keid’s inherent nervousness. In 2023, researchers had expressed serious doubts about the existence of this exoplanet. These new high-precision radial velocity measurements, which were not yet available in 2018, are the final nail in the coffin of the Vulcan-type HD 26965 b.
The disappointing news for Star Trek fans was announced by NEID, whose name rhymes with “fluid.” NEID is an instrument that uses radial velocity to measure the movement of nearby stars with extreme precision.
NEID separated the suspected planetary signal into its constituent wavelengths representing light emitted by various layers of Keid’s surface or photosphere structure. This allowed the team to detect significant differences between individual wavelengths compared to the total combined signal.
The upshot is that the signal implying the existence of HD 26965 b is actually the result of something that flickers on Keid’s surface approximately every 42 Earth days. This effect could also be created when hot and cold plasma rises and falls through the Keid convection zone and interacts with surface features such as dark sunspots or bright, active regions called “ranges.”
While this discovery is not good news for Keid and his planetary prospects, or for Star Trek fans, it is a positive step for exoplanet-hunting scientists.
Indeed, NEID’s finely tuned radial velocity measurements promise that planetary signals can be more accurately separated and distinguished from the natural jitter of stars in the future.
The team’s research is published in The Astronomical Journal.