No CrossRef data available.
Published online by Cambridge University Press: 04 August 2017
We have detected the 8.7 GHz hyperfine line of 3He+ in the HII regions W43, W51, and W3 and obtained significant upper limits for M17, W49, and Orion A. Even though the abundances derived from measured line parameters can have large uncertainty due to the detailed structure of the sources, it seems almost certain that the 3He+ abundance in W3, 12 kpc from the galactic center is significantly higher than in sources closer to the galactic center. If this is the result of general chemical evolution of the galaxy, it is exactly the opposite of what is expected.