LSS4005 AND NaStl, TWO GALACTIC Ofpe/WN or B[e] OBJECTS* K.A. van der Hucht, SRON Space Research Utrecht, The Netherlands P.M. Williams, Royal Observatory, Edinburgh, Scotland, U.K. A.M. van Genderen, Leiden Observatory, The Netherlands P. Mulder, Kapteyn Astronomical Institute, Groningen, The Netherlands W.J. Zealey, Department of Physics, University of Wollongong, Australia Optical and IR spectroscopy of two galactic objects previously considered to be extreme late WN stars (van der Hucht et al., 1984), LSS4005 (formerly tentatively listed as WR85a) and NaStl (WR122), show both objects not to be WR stars, but Ofpe/WN- or B[e]-like objects. A CASPEC spectrum of LSS4005 obtained in Spring 1985 displays numerous narrow (AA « 20 km.s -1 ) emission lines of Nil, [Nil], NIII, Fell, [Fell], FelH, [Felll] and strong emission of Hel and Hell. Except for SiIVA4089, no absorption lines are present in the 3800-6500A wavelength range and, in particular, no P Cygni absorption components. This indicates that LSS4005 does not have the dense stellar wind characteristics of WR stars. A medium-resolution CCD spectrum of NaStl shows strong similarities with LSS4005. IR spectra of NaStl in the J, H and K bands show Hel, Hell and Nil emission lines. Walraven photometry of both stars shows Balmer jumps indicative of effective temperatures of the order of 12000 K. Such temperatures are rather low for objects showing Hell emission lines. Walraven and ground-based IR photometry betray both objects to be light variables (Am « 0.2 mag for LSS4005, Am a 0.6 mag for NaStl), and to have heated (T « 900 K) circumstellar dust envelopes, showing wider ranges of temperature than those associated with WR stars (Williams et al., 1987). The low-ionization emission lines and the circumstellar dust shells point to a B[e] classification, but the Hell emission is indicative of an 0[e] class, while the NIII emission lines argue for a Ofpe/WN status. The composite appearance of both LSS4005 and NaStl could mean a double shell structure or binarity. In the literature the objects have no equals in the Galaxy nor in the LMC. More observations are needed to understand these enigmatic objects. References: van der Hucht, K.A., Williams, P.M., The, P.S.: 1984, in: A. Maeder & A. Renzini (eds.), Observational Tests of the Stellar Evolution Theory, Proc. IAU Symp. 105 (Dordrecht: Reidel), p. 273 Williams, P.M., van der Hucht, K.A., The, P.S.: 1987, Astron. Astrophys. 182, 91 *) Based on observations collected at the European Southern Observatory (La Silla, Chile), the United Kingdom Infrared Telescope (Mauna Kea, Hawaii, USA) and the Anglo-Australian Observatory (Epping, NSW, Australia) 301 K. Davidson et al. (eds.), Physics ofLuminous Blue Variables, 301. © 1989 by Kluwer Academic Publishers. use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0252921100004735 Downloaded from https://www.cambridge.org/core. IP address: 207.241.231.80, on 24 Jul 2018 at 06:25:38, subject to the Cambridge Core terms of