Stromgren and Hβ colors have been measured from spectrophotometric observations of two Be stars without published photometry in Per OB1: HD 12856 (BO pe) and HD 13890 (B1 III:pe). Stellar parameters and improved spectral types are then derived from the color indices and the calibrations of Jakobsen (1986a,b,c). These are compared with the parameters of normal B stars and they are used to estimate the evolutionary status of the stars.

L. Divan (1979) showed that the Balmer jump is greater in a Be-shell star than in a star of same spectral type and we will consider if this property is also present in A and F-shell stars by studying their data in the Geneva photometric system. Two photometric parameters in this system are correlated with the Balmer jump: d=(U-Bl) -1.430 (B1-B2) and Δ=(U-B2) -0.832 (B2-G). In addition to the Balmer jump, Δ is also sensitive to blanketing. Both parameters are reddening free. A study of the Be stars of luminosity class V or IV classified by Slettebak (1982) shows that, in a d vs Δ diagram, they are in the area of main sequence stars or a little above, while the majority of Be-shell stars are above the Be star sequence. Pleione is well known for presenting a Be phase followed by a shell phase.

Continued UV monitoring at high spectral resolution utilizing the International Ultraviolet Explorer (IUE) of the IRAS candidate proto-planetary system, Beta Pictoris (Also see Kondo and Bruhweiler 1985; and references cited therein.), has revealed two components to the circumstellar absorption. The first is a stable absorption component at or near the stellar photospheric velocity, possibly arising from gas orbiting in a gaseous disk, while the second component represents strong variable excess absorption sometimes extending up to +200 km s-1. The variability of this second component accounts for most of the spectral variability observed in Beta Pic. Variable circumstellar absorption observed in the resonance lines and UV62 and 63 multiplets of Fe II reveal an episode of mass inflow which lasted over a period of 12 to 13 months (see Fig. 1).

It is well known (cf. Mendoza 1983) that “classical“ Be stars, and Herbig Ae/Be objects, in addition to hydrogen lines in emission, also share at least two photometric characteristics, namely, light varitions, and infrared color excesses.

We have selected the α(16)⋀(9) {Mendoza 1979}, and the JHKL-photometric systems, in order to study some photometric properties of Be stars. The observations have been carried out at the National Astronomical Observatory (San Pedro Martir, B.C.N., and Tonantzintla, Pue.), Mexico, from 1976 to 1986.

After three specialized meetings on Be stars, it: appears that the Be phenomenon is more complicated than we have thought. Five fundamentally different models are now competing. All five are actually based on an assumption that the Be stars are only a specialized (perhaps more easily noticeable) case of a more general phenomenon. Carefully arranged observations may decide between competing concepts, for example between spheroidal and disk-shaped circumstellar envelopes, and they can decide on the location of the cool strata (emitting Balmer lines) and hot strata (N V, C IV, Si IV). Eclipsing interacting binaries provide valuable clues.