What To Know
- If this star has a planet orbiting it, the planet will exert a gravitational force above, which will lead to slight movements of the star in space.
- Their observations using NASA’s NEID instrument at Kitt Peak National Observatory have revealed that the fluctuations seen in the motion of the star Keid are not the result of an orbiting planet, but rather “pulses and tremors” of the star itself.
- These internal movements of the star can then manifest themselves on the surface of the star, creating fluctuations in its motion that can be observed from Earth.
A recent discovery in astronomy has cast a shadow over one of the most mythical stars in science fiction: Vulcan, the home planet of the famous Star Trek character Spock. Long suspected of orbiting the star 40 Eridani A, Vulcan seemed to be a confirmation of the convergence of science and fiction. However, new research suggests that Vulcan may be nothing more than an illusion created by the whims of its parent star, Keid.
Radial velocity
Imagine you are looking at a star from Earth. Normally, it emits light constantly. However, if this star has a planet orbiting it, the planet will exert a gravitational force above, which will lead to slight movements of the star in space. It’s a bit like holding a flashlight and shaking it slightly: the light emitted by the flashlight will flicker with the movement. Similarly, when the star is slightly “shaken” by the gravity of the planet, its light undergoes slight changes. These changes in the star’s light can be observed from Earth. When the star moves slightly towards us, the light it emits is “squeezed” and becomes slightly bluer. Conversely, when the star moves away from us, the light is “stretched” and becomes slightly redder. By measuring these subtle changes in the star’s light, scientists can then deduce the presence of a planet orbiting the star. The more massive the planet, the greater the star’s movements will be, and therefore the more pronounced the changes in its light will be. Four years ago, this method was used to suspect the existence of a planet around the star Keid. This observation had attracted great interest from scientists for its apparent similarity to the famous fictional planet Vulcan from the Star Trek universe. Twice as large as Earth, this planet seemed to orbit its star every 42 days, evolving in its habitable zone as it passed.
An illustration of HD 26965 b often compared to “Vulcan” from the Star Trek universe. Credits: JPL-Caltech/Robert Lea (created with Canva))
When science thwarts fiction
A team of researchers led by astronomer Abigail Burrows of Dartmouth College is now challenging this finding. Their observations using NASA’s NEID instrument at Kitt Peak National Observatory have revealed that the fluctuations seen in the motion of the star Keid are not the result of an orbiting planet, but rather “pulses and tremors” of the star itself. To understand this, imagine that the star is like a giant ball of jelly in space. Inside, there are all sorts of movements and jolts happening in different places. These internal movements of the star can then manifest themselves on the surface of the star, creating fluctuations in its motion that can be observed from Earth. These pulses and jolts can be caused by various astrophysical processes occurring inside the star, such as magnetic flares, density changes, or even more complex phenomena related to its internal structure. By carefully examining these fluctuations, astronomers were able to determine that they were the direct result of these dynamic features, rather than a planet orbiting it. This revelation has important implications. The results call into question not only the presumed existence of Vulcan, but also the reliability of methods for detecting exoplanets. Details of the study are published in The Astronomical Journal.
