(ORDO NEWS) — Using the “ultra-clear vision” of the Very Long Baseline Array (VLBA) radio observatory – a network of radio antennas that spans across the North American continent and operates as a single telescope – astronomers have discovered a planet the size of Saturn orbiting a small, cool star about 35 years from Earth.
This discovery was the first detection of an extrasolar planet using a radio telescope using a method that requires extremely precise measurements of the position of a star in the sky, and only the second detection of a planet using this method, as well as using a radio telescope.
This method has long been known to scientists, but its use has encountered great difficulties. The method includes determining the true motion of a star in outer space, followed by an analysis of tiny deviations in this motion caused by the gravitational effect on the star from the planet.
The star and planet revolve around a point representing the system’s common center of mass. A planet is detected indirectly if this point, called the barycenter, is located far enough from the star so that the displacements of the star can be detected with telescopes.
This method, called the astrometric method, is best for detecting Jupiter-sized planets orbiting host stars in wide orbits.
This is due to the fact that when a massive planet orbiting a star rotates, the magnitude of the observed deviations in the position of the star increases with an increase in the distance between the star and the planet, and at a given distance from the star, the deviation in the position of the star increases with increasing mass of the planet.
Since June 2018, astronomers led by Salvador Curiel of the National Autonomous University of Mexico have observed a star called TVLM 513-46546, a cold dwarf star less than one tenth the mass of the Sun. Detailed analysis of the data revealed displacements in the position of the star, indicating a planet with a mass on the order of the mass of Saturn, which orbits the star with a period of 221 days.
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