Line identification and photometric observations of the future planetary nebula IRAS 18 062+2410=V886 Her in 1997-1999

Photoelectric UBV observations of V886 Her in 1998-1999 have shown that the pattern of its variability is retained: irregular rapid light variations w ith an amplitude up to 0.(m)3 in V and the absence of any correlation betwe en color and magnitude. As previously, the amplitude was at a maximum in U, which is most likely attributable to the variable Balmer continuum emitted by stellar wind. A high-resolution spectrum of the star is identified. The overwhelming majority of absorption lines, apart from H I and He I, belong to O II, N II. C II, and Si III. The profiles of hydrogen and helium lines are a superposition of a stellar absorption line with comparatively broad wings and a narrow strong emission feature of the envelope. The He I 5016, 5876, and 7065 Angstrom lines have P Cyg profiles, whereas the remaining he lium lines are seen in absorption. The emission spectrum of the envelope is represented by numerous permitted and forbidden lines of ionized metals an d by [N II], [S II], and [O I] lines typical of planetary-nebula spectra, a s well as by strong O I, N I; and Si II lines. There are no [O III] lines. The radial velocity of the system measured from photospheric absorption fea tures is [V-r(NII, OII, CII, SiIII)] = +55.72 km s(-1), while the mean radi al velocity as measured from emission features of the envelope is +50.95 km s(-1). The object is most likely an extremely young planetary nebula. (C) 2001 MAIK "Nauka/Interperiodica".