Abstract
We present the first far-UV spectra of the Herbig Be star HD 100546, observed by the Far Ultraviolet Spectroscopic Explorer (FUSE )a s part of theCircumstellar Disks team program. We identified and analyzed numerous narrow absorption lines of circumstellar origin. Intense, broad and fairly asymmetric emission lines of C ,C ,O and S were also detected, spanning temperatures up to 3 × 10 5 K. Comparison of the spectra recorded two years apart reveals strong spectral variations, not only in the emission lines but also in the circumstellar lines of N ,N ,O ,A r and Fe . The varying absorption lines of N and O exhibit the largest velocity width, from −200 to +320 km s −1 , relative to the star's rest-frame. Variations on a timescale of an hour occurred only in the N resonance triplet and O ( 1 D) lines. The spectroscopic variability highlighted by these two observations and the line profile analysis reveal signatures of both outflow and infall processes, which appear to be related in this system. We suggest that these spectral signatures originate in a stellar magnetosphere, which likely interacts with the innermost part of the star's circumstellar disk. This interpretation can account for the main features observed in the spectrum of HD 100546: variable emission and absorption lines as well as suspected continuum variation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
