European astronomers have noticed a group of stars moving at high speed and outside the solar system's orbit around the center of the Milky Way. This group of stars, which move significantly faster than most of the surrounding stars, could provide valuable insights into stellar dynamics, according to new scientific work.
The discovery was made by a team of researchers led by Jason Hunt of University College London, United Kingdom, based on an analysis of scientific data collected by the European Space Agency's Gaia satellite. The spacecraft is currently completing a survey of one billion stars in our Galaxy and its environs, measuring the position of the stars with an accuracy of the order of a few angular microseconds.
Astronomers have calculated that the group of stars they discovered is orbiting the center of the Milky Way at a speed of about 20 kilometers per second, which is significantly higher than the average speed of rotation around the center of the Galaxy of other stars located at about the same distance from its center. To explain these observations, Hunt's team suggested that the excess acceleration received by these stars could be due to the gravitational effects of one of the main spiral arms of the Milky Way galaxy, the Perseus Arm.
This explanation, in turn, can be based on one of two different ideas about the nature of the motion of the Perseus spiral arm around the center of our Galaxy. According to the first of these models, the spiral arm moves through the galactic disk as a wave at a constant speed, while the second model assumes that the spiral arm moves at the same speed as the movement of these stars. The results obtained by Hunt's team do not make it possible to unambiguously determine in favor of one of these scenarios, but they agree better with the second of these models.
The study appeared on the arxiv.org advanced scientific publications server.