Scientists from the U.S. National Institute of Astrophysics have tracked the super-earth next to the star closest to the sun. An analysis of the cyclical changes in the light spectrum emitted by Proxima Centauri allowed researchers to suggest that a second planet could be in its orbit.
Researchers Mario Damasso and his colleagues have cited evidence that this candidate planet moves in the orbit of Proxima Centauri every 5.2 years. According to their assumption, this is super-earth with a mass exceeding the mass of the Earth, but at the same time lighter than Uranus and Neptune.
If its existence is confirmed, then this planet can give an idea of how low-mass planets are formed around low-mass stars. This information will contradict the models of how super-earths are born; it is believed that most of them form at a minimum distance from the star, at which water can turn into ice. This planet does not fit into this model.
A previous study by Proxima Centauri using the Atacama Large Millimeter Array (ALMA), an astronomical observatory in northern Chile, reported an unknown source of light spectral signals that could belong to a second planet or simply be a product of a neighboring galaxy or an unrelated phenomenon.
To better understand if the signal comes from another planet orbiting a star, Mario Damasso and his colleagues analyzed 17.5-year time series of high-precision radial velocities using an exoplanetary detection method that tracks the light spectrum of a star. The researchers found that the signal occurs within 1900 days, which indicates that it is probably not associated with cyclic shifts in the magnetic field of the star. However, the authors emphasize that more evidence is needed to confirm their findings.