A spectral atlas of λ Bootis stars

• Main Authors: Paunzen E., Heiter U.
• Format: Article
• Language: English
• Published: Astronomical Observatory, Department of Astronomy, Belgrade 2014-01-01
• Series: Serbian Astronomical Journal
• Subjects: atlases; stars: chemically peculiar; stars: fundamental parameters
• Online Access: http://www.doiserbia.nb.rs/img/doi/1450-698X/2014/1450-698X1488075P.pdf

Since the discovery of λ Bootis stars, a permanent confusion about their classification can be found in literature. This group of non-magnetic, Population I, metal-poor A to F-type stars, has often been used as some sort of trash can for "exotic" and spectroscopically dubious objects. Some attempts have been made to establish a homogeneous group of stars which share the same common properties. Unfortunately, the flood of "new" information (e.g. UV and IR data) led again to a whole zoo of objects classified as λ Bootis stars, which, however, are apparent non-members. To overcome this unsatisfying situation, a spectral atlas of well established λ Bootis stars for the classical optical domain was compiled. It includes intermediate dispersion (40 and 120Å mm-1) spectra of three λ Bootis, as well as appropriate MK standard stars. Furthermore, "suspicious" objects, such as shell and Field Horizontal Branch stars, have been considered in order to provide to classifiers a homogeneous reference. As a further step, a high resolution (8Å mm-1) spectrum of one "classical" λ Bootis star in the same wavelength region (3800-4600Å) is presented. In total, 55 lines can be used for this particular star to derive detailed abundances for nine heavy elements (Mg, Ca, Sc, Ti, Cr, Mn, Fe, Sr and Ba).