mercury-manganese star

mercury-manganese star

[′mər·kyə·rē ′maŋ·gə‚nēs ′stär]
(astronomy)
A star of spectral type B8 or B9 that has a variable spectrum displaying excesses of phosphorus, manganese, gallium, strontium, yttrium, zirconium, platinum, and mercury, and lacks a strong global magnetic field.
References in periodicals archive ?
These are: Am stars, which show strong heavy metal lines, no magnetic field, and and are slow rotators; Ap stars, which show lines of strontium, chromium and rare earth elements, a strong magnetic field, and generally slow rotation; mercury-manganese stars, which show abundance of singly ionised Hg and Mn, but weak magnetic fields and very slow rotation rates; and finally, helium-weak stars, which have weaker helium lines than would be expected from their colour.
The mercury-manganese stars may be explained by a diffusion model.