A Detailed Far-Ultraviolet Spectral Atlas of Main Sequence B Stars

TL;DR

This paper presents a comprehensive ultraviolet spectral atlas for 10 main sequence B stars, including detailed line identifications and potential diagnostic lines, based on archival and high-resolution spectra.

Contribution

It provides the first detailed spectral atlas with extensive line identifications for B stars in the far-ultraviolet range, including supplementary data and diagnostic line candidates.

Findings

Identified 92-98% of spectral lines with known atomic transitions.

Compiled a list of 167 least blended lines for atmospheric diagnostics.

Achieved high identification certainty for most atomic features.

Abstract

We have constructed a detailed spectral atlas covering the wavelength region 930A to 1225A for 10 sharp-lined B0-B9 stars near the main sequence. Most of the spectra we assembled are from the archives of the FUSE satellite, but for nine stars wavelength coverage above 1188A was taken from high-resolution IUE or echelle HST/STIS spectra. To represent the tenth star at type B0.2 V we used the Copernicus atlas of tau Sco. We made extensive line identifications in the region 949A to 1225A of all atomic features having published oscillator strengths at types B0, B2, and B8. These are provided as a supplementary data product - hence the term detailed atlas. Our list of found features totals 2288, 1612, and 2469 lines, respectively. We were able to identify 92%, 98%, and 98% of these features with known atomic transitions with varying degrees of certainty in these spectra. The remaining lines do not have published oscillator strengths. Photospheric lines account for 94%, 87%, and 91%, respectively, of all our iden- tifications, with the remainder being due to interstellar (usually molecular H2) lines. We also discuss the numbers of lines with respect to the distributions of various ions for these three most studied spectral subtypes. A table is also given of 167 least blended lines that can be used as possible diagnostics of physical conditions in B star atmospheres.