Thanks to the Gaia telescope, astronomers have determined the exact distance to the North Star and it is 447 light years with an error of 1.6 light years. In addition, scientists also revised the radius, age and mass of the star.
Despite the fact that the North Star is one of the most famous stars in the sky, which is mentioned in the catalog of stars "Almagesta" compiled by Ptolemy almost two thousand years ago, scientists still could not accurately determine the distance to it. Current estimates gave values from 322 to 520 light years, which also prevented the study of the properties of the star. However, now, thanks to a new release of the Gaia telescope data, published in April, astronomers were able to get the exact value.
In fact, the Polar Star is a system of three luminaries: the main thing is that the Polar A is a supergiant around which two smaller stars rotate - Polar B and Polar Ab (or P). In the new work, astronomers Scott Engle, Edward Ginan and Peter Harmanets analyzed the data obtained by Gaia for component B, stars with a mass of 1.39 solar masses.
The measurements showed that the distance to the star reaches 447 +/- 1.6 light years, which can be applied to the entire system. The absolute magnitude of Polar B is 2.91. This value is slightly higher than that expected for a star of spectral type F3V at the age of 60-100 million years. In addition, astronomers specified the properties of the main star, Polar A: its radius is 47-50 solar radii, and the mass 6.4-4.6 times the mass of the Sun, its age is 55-65 million years.