******************************************* * * * INTRODUCTION TO THE ONLINE VERSION * * * ******************************************* The objects listed in this catalogue are subdivided into three main object classes, i.e. into " C A T A C L Y S M I C B I N A R I E S ", " L O W - M A S S X - R A Y B I N A R I E S " and " R E L A T E D O B J E C T S ". The defining characteristics of the three object classes used here are the following: C A T A C L Y S M I C B I N A R I E S are semidetached binaries consisting of a white-dwarf primary (or a white-dwarf precursor) and a low-mass secondary which is filling its critical Roche lobe. The secondary is not necessarily unevol- ved. It may even be a highly evolved star as for example in the case of the AM CVn-type stars. A more detailed description of the main characteristics of these objects may be found in Warner (1995). In addition, we list among the cataclysmic binaries also the su- persoft binary X-ray sources, because these too are semidetached binaries containing a white dwarf, though one in a state of sus- tained nuclear burning. More information about these objects can be found in Greiner (1996). L O W - M A S S X - R A Y B I N A R I E S are semidetached binaries consisting of either a neutron-star or a black hole primary and a low-mass secondary which is filling its critical Roche lobe. Observationally they are distinguished from the luminous, massive X-ray binaries by the following main proper- ties: in general the spectra of the low-mass X-ray binaries (at maximum light) are devoid of normal stellar absorption features. The ratio of their X-ray to optical luminosities is much larger than unity, (typically it ranges from about 100 to about 10000). A more detailed description of the main characteristics of these objects may be found among the review articles in Lewin, van Para- dijs and van den Heuvel (1995) R E L A T E D O B J E C T S are detached binaries consisting of either a white dwarf or a white dwarf precursor primary and of a low-mass secondary. The secondary may also be a highly evolved star. Further information may be found e.g. in Ritter (1986), Bond (1989), or de Kool and Ritter (1993). With one possible exception (HD 49798) we do not list among the related objects detached binaries containing a neutron star, or, for the lack of known objects, a black hole. Thus we explicitly exclude binary radio pulsars from our compilation because these are adequately documented elsewhere (e.g. in the Princeton pulsar list (Taylor, Manchester and Lyne 1993) and its updates (available via anonymous ftp at pulsar.princeton.edu)). According to the subdivision in these three object classes the catalogue contains three major sections, hereafter called catalogue sections. Each of the three catalogue sections is further subdivided into a table section (TS), where a few characterizing parameters of the object are tabulated, and into a reference section (RS), where a selection of refe- rences is given. Within each of the table sections, the objects are listed in order of decreasing orbital period. In the corresponding re- ference section, however, the objects are listed in lexigraphical order. The quantities listed in the table section and the corresponding abbreviations used in the table headings are described in a separate "Description" section. In contrast to the previous editions we provide now limited information about where the values given in the tables are taken from. This is done as follows: at the end of a reference from which a given quantity, say XYZ, was taken, this quantity is given in parenthesis, i.e. as (XYZ). The quantities for which this is done are: the periods (Orb.Per., 2. Per., 3. Per., 4. Per), the spectral types (Spectr1, Spectr2), the mass ratio (M1/M2), the orbital inclination (Incl), the masses (M1, M2), and, where appropriate, the radii (R1, R2) and the eccentricity (e). The catalogue is supplemented by a list giving references to published finding charts (FC) of the objects. In this section, the objects of all three classes are merged and listed in lexigraphical order. The full form of abbreviated references is given at the end of the section. The "Who's Who?" section is a cross-reference list of alias names of the objects catalogued. In order to keep this list short, the full ist of alternative object names appears only once for each object and is to be found under the standard name used in this catalogue. If an object is sought under one of its alternative names, reference to the standard name is given. Wherever possible the variable name given in the 4th edi- tion of the General Catalogue of Variable Stars (Kholopov et al. 1985a, 1985b, 1987) or in the Name Lists of Variable Stars (up to and including the 73rd list (Kazarovets and Samus (1997), and references therein) is used as the standard name here. This section includes also a list of re- ferences to various catalogue acronyms that appear in this compilation. A more complete list of this kind may be found in "The First Dictionary of the Nomenclature of Celestial Objects" by Fernandez, Lortet and Spite (1983) and its supplements Lortet (1986a,b) and Lortet and Spite (1986), or online via the CDS at http://vizier.u-strasbg.fr/cgi-bin/Dic, or from the ADC at http://adc.gsfc.nasa.gov/adc/. References ---------- Bond, H.E. 1989, in: Planetary Nebulae, S. Torres-Peimbert (ed.), Kluwer, Dordrecht, p. 251 de Kool, M., Ritter, H. 1993, A&A 267, 397 Fernandez, A., Lortet, M.-C., Spite, F. 1983, A&AS 52(4) (1983) Greiner, J. (ed.) 1996, Supersoft X-Ray Sources, Lecture Notes in Physics Vol. 472, Springer-Verlag, Berlin Kazarovets, E.V., Samus, N.N. 1997, IBVS No. 4471 Kholopov, P.N., et al. (11 authors) 1985a, General Catalogue of Variable Stars, 4th edition, (Moscow, Nauka), Vol. I Kholopov, P.N., et al. (13 authors) 1985b, General Catalogue of Variable Stars, 4th edition, (Moscow, Nauka), Vol. II Kholopov, P.N., et al. (13 authors) 1987, General Catalogue of Variable Stars, 4th edition, (Moscow, Nauka), Vol. III Lewin, W.H.G., van Paradijs, J., van den Heuvel, E.P.J. (eds.) 1995, X-Ray Binaries, Cambridge Astrophysics Series Vol. 26, Cambridge University Press, Cambridge Lortet, M.-C., 1986a, A&AS 64, 303 Lortet, M.-C., 1986b, A&AS 64, 325 Lortet, M.-C., Spite, F. 1986, A&AS 64, 329 Ritter, H. 1986, A&A 169, 139 Taylor, J.H., Manchester, R.N., Lyne, A.G. 1993, ApJS 88, 529 Warner, B. 1995, Cataclysmic Variable Stars, Cambridge Astrophysics Series Vol. 28, Cambridge University Press, Cambridge