4 Catalogue of spectral types for the cool giants in symbiotic systems

In Table 5 we present a catalogue of spectral types for the cool components in symbiotic systems. The catalogue is mainly based on our classifications described in the previous Section. For those objects where we found different spectral types for different observations, we entered in Table 5 the "average''. For objects not covered by our own observations we adopt published spectral types when available. We believe most literature classification to be less accurate than our own, the exceptions being the spectral types from Schulte-Ladbeck (1988) and Kenyon & Fernández-Castro (1987) (see the discussion in Sect. 3.2). The catalogue contains 179 entries, of which 172 objects have a spectral classification for the cool giant. In this work, we classified 97 objects, many for the first time.

The catalogue includes the following objects:

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all systems contained in the catalogue of Allen (1984), including the "possible symbiotic stars'';

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all additional objects listed in Mikoajewska et al. (1997);

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the systems identified by Cieslinski et al. (1994, 1997, 1998);

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all systems in the Magellanic Clouds included in the Paper by Mürset et al. (1996);

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in addition: MWC560 (Michalitsianos et al. 1991), S32 and S190 (Downes & Keyes 1988), and LMC N19 (Morgan 1996).

We did not attempt to present a complete list of all objects claimed to be symbiotic in the literature since we suppose that some identifications would require closer re-inspection which is beyond the present scope.

The catalogue gives also the classification into s-, d-, and d$^\prime$-types according to the IR colors (see Webster & Allen 1975; Allen 1982). The s-types show in the IR a normal continuum of a cool giant, while d- and d$^\prime$-types show strong dust emission. The s-types contain non-variable red giants and typically have binary periods of $P\approx1-3$ years. d-type systems probably all contain a mira variable as cool component and have probably very long orbital periods P>20 yr. The d$^\prime$-types have several special properties, the most conspicuous of which is the presence of a F- to early K-type giant instead of a cooler star.

The IR classifications given in Table 5 are adopted from Allen (1984), Mikoajewska et al. (1997), and Mürset et al. (1996), with a few exceptions: V417 Cen was classified d$^\prime$ by Van Winckel et al. (1994). He2-147 is of type d according to Whitelock (1987). Hen1591 is classified as d-type by Allen (1984); however, in view of the early spectral type d$^\prime$ seems to be more appropriate. In the catalogue there are 133 s-types, 30 d-types, 7 d$^\prime$-types and 9 objects with no IR classification.