HD 15570 : a star intermediate between Of and WN7 ?
Willis, A. J.; Stickland, D. J.
United Kingdom, Spain
Abstract
IUE ultraviolet observations of HD 15570, classified in the visible as O4f, show the presence of N IV wavelength 1486 and He II wavelength 1640 strongly in emission, spectral characteristics which are signatures of WN stars rather than Of stars. A comparison of the UV spectra of this star with those of Xi Pup (O4f), HD 164794 (O4V) and HD 93131 (WN7) suggests that HD 15570 may be intermediate in type between Of and WN7 and may represent an evolutionary link between these two stellar classes.