Since the time of I.A.U. Colloquium n° 70, new data have been obtained in the infrared, far less however than in the ultraviolet or in the visible. Few line spectra have been recorded but numerous results have been published in the field of spectrometry of the continuum. It is however neither easy nor very useful to report on the infrared wavelength range alone, and therefore we shall consider when appropriate other spectral regions in this review. After all, the astrophysicist nowadays has the advantage to seek for information in a spectrum which encompasses a fantastic frequency range of about 10 dex, from ν = 108s−1 up to ν = 1018s−1. This means that a contemporary astronomer will have to become familiar with a somewhat larger span of phenomena than with the rather narrow one he has been accustomed to for the last 40 or 50 years.

Among the 0 stars, Conti and Leep (1974) define the Oe class as those stars showing emission in the hydrogen lines but without emission in N III or 4686 He II.

In the blue-red region, aside from the presence of Lambda 4542 in absorption, the overall appearance is similar to Be stars. So far no Oe star has been observed until 1.1 μ: the aim of this paper is to fill this gap. We present observations of Oe stars in the near infra-red region as well as new observations of Hα profiles.

A photometric study of Be stars in the JHKL system is reported here. Early papers (see Feinstein and Marraco, 1980) about bright southern Be stars observed photoelectrically in the UBVRI system and in the Balmer-lines: Hα, Hβ and Hγ, permit us to derive several conclusions about their light variability, the amount of emission in the α and β indices, and some correlations about these data. On the other hand, we recently found (Feinstein and Marraco, 1981) that the emission strengths of the hydrogen lines are well correlated to the amount of excess radiation in the near-in-frared of the RI system.

Thirty-five peculiar emission line objects (essentially B[e] stars) were observed at J(1.2 μ), H(1.6 μ), K(2.2 μ), L(3.5 μ), and M(4.8 μ) at the E.S.O. 1 m telescope where the photometer is equipped with an InSb detector. The results of the observations performed during several nights and days in Feb. 1979 and March 1980 are listed in Table 1.

Preliminary results of our infrared observations from 2.3 up to 10 and 20 microns of the Be-X-ray stars X Per, γ Cas and HDE 245770, indicate the presence of an ionized circumstellar disk with an electron density law of the type ne ∝ r−3.5. x Per and γ Cas show besides, variable infrared excess at 10μ suggesting variability in the stellar wind. LS I+65°010 presents an anomalous infrared energy distribution for a Be star.

This paper describes preliminary results from a digital analysis of the Fourier transform spectroscopy of β Lyrae. The spectra are photometrically precise in the 4800–10200 Å range with a spectral resolution of 3.85/cm. The most remarkable spectral features are the emission strength of some neutral Helium and Hydrogen lines, and their vari ability with time. Other fainter emission lines disappear, now and then.

As you know the first list of bibliography on Be stars was published in the second Be Star Newsletter. Six contributors are trying to cover the production of papers in the field. No doubt that the bibliography is very useful and I am very glad that Dr. M. Jaschek has offered the Newsletter for this purpose and that she is acting as the editor of the bibliography.

We are presently undertaking, at the Stellar Data Center, a large effort to produce the Catalogue of Stellar Groups, which is a catalogue listing all the kinds of stars with spectral peculiarities existing up to now. The work is in progress and presently about fifty groups (Ap, Am, Be, WR, H and K emission line stars, etc.) are defined, gathering more than 25000 stars. The catalogue was started with the aim to set up lists defined by homogeneous criteria, because up to now the available information is scattered through the literature. We hope that the catalogue will be useful for formulating observing programs and for further detailed research on each of the groups.

A catalogue of quantitative observations of Hα published between 1949 and 1980 has been prepared. It contains 4095 measurements concerning 2700 stars.

Most of our present-day knowledge of the photometric behaviour of Be stars still comes from various surveys only. Little attention was paid to systematic studies of possible photometric variability of particular objects on different time scales. Nevertheless, just this kind of information is necessary if one wants to study the physical relationship and/or differences between Be stars and other types of B stars like Beta Cepheids, supergiants, helium-rich stars etc., and to test various models of the Be phenomenon. Long systematic photoelectric observations do exist only for several Be stars. They invariably indicate that the long-term variability - if present - is always the most pronounced one. In some cases, this long-term variability masks the periodic light variations occuring on shorter time scales (see, e.g., the case of CX Dra, Koubský et al 1980).

With organization of the Photometric Observing Campaign well under way, there is an exciting opportunity for collaboration amongst the spectroscopists. I am proposing a program of regular ground-based spectroscopy of the 100 or so brightest northern Be stars, to be contemporaneous with the photometric program.

In recent years there is a general tendency to divide Be stars into different groups. Bidelman's (1976) division on supergiants, rapidly rotating single stars, interacting binaries, early type nebular variables and quasi (or young) planetary nebulae is often quoted. Another example is the classification by Lesh (1968) or a very recent classification by Jaschek et al (1980), limited a priori to “normal” Be stars i.e. stars of luminosity classes V to III. I do not think such an approach is recommendable. There is still no general agreement as to the nature of the Be phenomenon and all such classifications must be more or less descriptive. The possibility that the hydrogen emission observed in the spectra of apparently very different objects has always the same physical cause, and that the differences between these objects are caused only by continuously varying physical and/or geometrical parameters should seriously be considered, along with all other concepts. At the moment, I find it more promising to study Be stars in context of all early type emission objects, including supergiants, P Cyg stars, Beta Cep objects, WR stars, symbiotic stars and novae. Such a viewpoint is not new – it was expressed already by Struve (1942).

Rotation can significantly change the moment-of-inertia of a main sequence star. As a result, the ZAMS rotation rate need only be within ~30% of the critical value in order to reach critical rotation during the hydrogen burning stage. Calculations of the evolution of rotating stars show that the Be stars result from a normal (Maxwellian) distribution of B-star rotation velocities.

For a grid of rotating hot stars the computed line widths at the half maximum depth for the lines HeI λ 4471 and MgII λ 4481 are given. Based on the correspondent observational data the inclination of the rotational axes i and the reduced rotational velocity w have been found for 19 B and Be stars.

At the last IAU Symposium on Be stars held in Bass River, MA in 1975, several of us (including P. Harmanec, M. Plavec, R.S. Polidan, and myself) suggested that Be stars are mass transfer binaries and represent the higher mass counterparts to the familiar Algol systems. Although a number of alternatives to the rotational hypothesis have been presented at this symposium (including “chromospheric” activity and non-radial pulsation) and some of these may well explain certain objects, I strongly believe that binary mass transfer is responsible (either directly or indirectly) for the circumstellar envelopes observed in a large percentage of Be stars.

The bright Be star o And has been observed for over 90 years. Throughout this time numerous observers detected highly variable spectrum, photometric changes and substantial range of radial velocity of this star. Much effort has been devoted for period searching in these data. In the present study we collected all available (to our knowledge) radial velocities and photometric measurements in the visible region and tried to evaluate the reported periodicities.

C IV and Si IV resonance line profiles of 21 Be, B-shell and normal stars are studied with the aim of detecting evidences for mass loss. We found that almost all our sampled stars are loosing mass. A relation between an estimated lower limit for the rate of mass loss and the observed rotational velocity was searched but not found.

Be star binaries with neutron star companions are shown to constitute a major class of X-ray sources. Some general observational and interpretive techniques of X-ray astronomy are reviewed. Data for 12 Be/X-ray binary systems are summarized. The Be/X-ray binaries are found to be systematically wider systems, with lower-mass primaries, and with significantly more transient behavior than the “standard” massive X-ray binaries such as Cen X-3 and SMC X-1. The difference between the two types of X-ray binaries is explained in the context of slightly different evolutionary scenarios for the progenitor binaries. The “standard” massive X-ray binaries result from wind-mass-loss dominated evolution of very massive close binaries, while Be/X-ray binaries probably result from mass-transfer dominated evolution of systems with primary masses ≲ 20 M⊙. The implications of the X-ray observations of Be/X-ray binaries for Be stars in general are discussed.

The Be X-ray binaries show rather weak and variable X-rays. They can be divided into two types, the transient sources and the permanent sources. Two ranges for the X-ray luminosity Lx can be discerned: a) Lx~1034erg s−1 (X Per, λ Cas, 2S0114+65, all permanent sources); b) Lx~1036erg s−1. They have long periods, hence wide orbits, they ar not eclipsing and their mass loss rates are low. The optical spectra are generally very variable and irregular, masking periodic changes. No optical orbits exist and only for 4U0115+63 an X-ray orbit is known (Rappaport et al.1978). An overview of the Be X-ray binaries with some of their characteristics is given in Table 1.

A point summation technique was used to search the UHURU data base for X-ray emission from classical Be stars. Of the thirty-two stars considered, only three (λ Cas, HR 4009, and HD 187399) were detected at the 3.3σ level or higher. For reasons discussed in this paper, HD 45314, π Aqr, κ Dra, and 48 Per are considered to be possible detections. The X-ray emission from λ Cas from late 1970 through early 1973 is discussed.