Print Recently, the journal of “Scientific American” publish the cover paper named “new view of the Milky Way” written by Mark J. Reid, a senior radio astronomer of Harvard & Smithsonian Center for Astrophysics and ZHENG Xingwu, a professor of astronomy of Nanjing University in China.
As one of authors of this study, Prof. WU Yuanwei from the National Time Service Center of the Chinese Academy of Sciences, spend more than 10 years on this project, lead the study of the Sagittarius arm, that for the first time pinpoint the location of the Sagittarius arm far (~ 10 kpc) beyond the tangent point of the arm, one of the major spiral of our Galaxy, which is a substantive part of such “new view of the Milky Way”. Related results were published on the astrophysics Journal in 2019.
"This international Astrometry project, named Bar and Spiral Structure Legacy (BeSSeL) led by Prof. Mark J. Reid, Xing-Wu Zheng and Karl Menten, the director of Max-Plank Institute for radio astronomy, investigated the structure of the Milky Way with the technology called VLBI maser astrometry in the past of 15 years." Prof. WU said
Researchers have measured about 200 parallax-based distances for young hot stars across large regions of the Milky Way. These data, which give us good coverage of about one third of the Milky Way, reveal at least four major spiral arms in the Milky Way, as well as some smaller features, and shows that the sun lies almost exactly on the central plane of the disk of the galaxy.
By modeling the motions of these massive stars, researchers estimated values for fundamental parameters of the Milky Way. The distance from the sun to the galaxy’s center is 8,150 ± 150 parsecs (or 26,600 light-years). This is smaller than the value of 8,500 parsecs recommended decades ago by the International Astronomical Union.
Also, they find that the Milky Way is spinning at 236 kilometers per second, which is about eight times the speed at which Earth orbits the sun, the sun circles the Milky Way every 212 million years.
Milky Way (credit by: Credit: Xing-Wu Zheng & Mark Reid BeSSeL/NJU/CFA)
For more related links:
Scientific American cover paper : https://www.scientificamerican.com/magazine/sa/2020/04-01/
High resolution photographs of the Milky Way : https://astronomy.nju.edu.cn/xtzl/
Trigonometric Parallaxes of High-mass Star-forming Regions: Our View of the Milky Way
https://iopscience.iop.org/article/10.3847/1538-4357/ab4a11
Trigonometric Parallaxes of Star-forming Regions beyond the Tangent Point of the Sagittarius Spiral Arm
https://iopscience.iop.org/article/10.3847/1538-4357/ab001a