The Puzzle of the Metallic Line Stars

Details The Puzzle of the Metallic Line Stars The Puzzle of the Metallic Line Stars

Mar 2006

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006pasp..118..419b&link_type=abstract

The Publications of the Astronomical Society of the Pacific, Volume 118, Issue 841, pp. 419-435.

Astronomy and Astrophysics

Astronomy

7

Stars: Chemically Peculiar, Stars: Magnetic Fields, Accretion, Accretion Disks

Scientific paper

In the puzzle of the metallic line (Am) stars, there still seem to be missing pieces. While the ``normal'' A stars have elemental abundances close to solar, the classical Am stars show stronger absorption lines for most heavy elements in their spectra. Elements with ionization potentials that nearly agree with those of hydrogen or helium have reduced abundances. The Ca II and Sc II lines are especially weak. The Am stars have no ultraviolet emission lines. They are binaries that, with very few exceptions, have rotational velocities vsini lower than 100 km s-1. Of the main-sequence A stars, 20% to 30% are Am stars. Here we rediscuss previous suggestions that tried to explain the peculiar line strengths in the Am star spectra. In particular, we compare the well-studied properties of Hyades A and Am stars in order to identify reasons that can or cannot explain the differences. We find that accretion of interstellar material by A stars with distorted magnetic fields, which are weaker than those in peculiar A (Ap) stars, has the best chance of explaining the main characteristics of the peculiar heavy-element abundances in Am star photospheres. Charge-exchange reactions also seem to be important.

Affiliated with

Also associated with

No associations

Rating

The Puzzle of the Metallic Line Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Puzzle of the Metallic Line Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Puzzle of the Metallic Line Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-980565