5 research outputs found
Long-term spectroscopic monitoring of the Luminous Blue Variable HD160529
We have spectroscopically monitored the galactic Luminous Blue Variable HD
160529 and obtained an extensive high-resolution data set that covers the years
1991 to 2002. During this period, the star evolved from an extended photometric
minimum phase towards a new visual maximum. In several observing seasons, we
covered up to four months with almost daily spectra. Our spectra typically
cover most of the visual spectral range with a high spectral resolution (about
20,000 or more). This allows us to investigate the variability in many lines
and on many time scales from days to years. We find a correlation between the
photospheric HeI lines and the brightness of the star, both on a time scale of
months and on a time scale of years. The short-term variations are smaller and
do not follow the long-term trend, strongly suggesting different physical
mechanisms. Metal lines also show both short-term and long-term variations in
strength and also a long-term trend in radial velocity. Most of the
line-profile variations can be attributed to changing strengths of lines.
Propagating features in the line profiles are rarely observed. We find that the
mass-loss rate of HD 160529 is almost independent of temperature, i.e. visual
brightness.Comment: 14 pages, 15 figures, accepted for publication in Astronomy &
Astrophysic