Chinese astronomers have reconstructed the most detailed rotation curve of the Andromeda galaxy (M31) ever created, estimating that the mass of this galaxy is about 1.14 trillion times that of the Sun, China Daily reported, cited by Agerpres.

The study, conducted by researchers from Yunnan University and other institutions in China, was recently published in the journal Monthly Notices of the Royal Astronomical Society. Located approximately 2.5 million light-years from Earth, the Andromeda Galaxy is the nearest large spiral galaxy to the Milky Way, forming an ideal astrophysical laboratory for studying galaxy formation and evolution.

“However, the galaxy’s great distance from Earth has made it difficult for astronomers to identify celestial bodies in it, and the lack of information about the movement of these celestial bodies has made it extremely difficult to accurately determine the galaxy’s rotation curve,” said Chen Binqiu, a professor at Yunnan University and co-author of the study, cited in Science and Technology Daily.

In this study, the Chinese team collected radial velocity measurements for 13,679 celestial bodies in the Andromeda galaxy and determined the rotation curve within a radius of 407,600 light-years from its center with an accuracy of 5 to 20 percent.

Studies have shown that this rotation curve remains relatively constant at about 220 kilometers per second inside its galactic disk, but gradually decreases outward to about 170 kilometers per second in its outer halo.

Based on the rotation curve, researchers from this group built a three-component mass model for the Andromeda galaxy, which shows the distribution of mass in the galaxy.

According to Professor Chen Binqiu, the research provides a new understanding of the mass distribution of the Andromeda Galaxy and, as a result, of spiral galaxies in general, which is important for further understanding of the dynamical structure, formation and evolution of spiral galaxies.

The researchers made the measurements using spectral data collected by the Large Sky Area Fiber Optic Spectroscopic Telescope (LAMOST), as well as other studies and observations.