Mercury in a thin layer in HgMn stars: A test of a diffusion model

Journal Article · Tue Jul 01 04:00:00 EDT 1980 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/158103· OSTI ID:6735387

Megessier, C; Michaud, G; Weiler, E J

Lines of the first three states of ionization of mercury have been observed in ..mu.. Leporis and chi Lupi using the Copernicus satellite. Lines of Hg II and Hg III have been observed in ..cap alpha.. Andromedae. There appears to be an absorption feature at every wavelength where there is expected to be a mercury line. The presence of all three states of ionization is likely in ..mu.. Lep and chi Lup. The relative equivalent widths of the lines of the various states of ionization do not depend on the effective temperature of the stars, in contradiction to what is expected if mercury were uniformly distributed in the atmosphere. It is, however, expected if mercury has been concentrated, by diffusion, in a thin layer, where the radiative forces just equal the gravitational forces on mercury. That mercury should be so concentrated is also required by the explanation of the mercury isotope anomaly proposed by Michaud, Reeves, and Charland. The diffusion model for Ap stars predicts in its simplest form the presence of very thin layers. However, any leftover turbulence may increase the depth of these layers without eliminating the element separation.

• Research Organization: Observatoire de Paris
• OSTI ID: 6735387
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 239:1; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
CHARGED PARTICLES
CHEMICAL COMPOSITION
DIFFUSION
IONS
ISOTOPES
LINE WIDTHS
MATHEMATICAL MODELS
MERCURY IONS
MERCURY ISOTOPES
SPECTRA
STAR MODELS
STARS
STELLAR ATMOSPHERES
ULTRAVIOLET SPECTRA
VARIABLE STARS
VISIBLE SPECTRA