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D.C. Black, T.F. Stepinski (Lunar and Planetary Institute)
High accuracy spectroscopic surveys have found 51 solar-type stars showing periodic residual radial motion of very low amplitude. The prevailing interpretation is that observed residual motion is due to the presence of an unresolved companion of approximatley Jupiter mass -- an extrasolar planetary candidate (EPC). However, the masses of these companions remains unknown, subject to determination of their orbital inclination. Thus, the classification of these companions as EPCs is based on a statistical argument and an assumption about the distribution of orbital plane inclination angles. On the other hand, orbital periods and eccentricities of EPCs are directly provided by the data and have no ambiguities associated with their values. We have shown that the probability densities of orbital periods and eccentricities for the population of EPCs are virtually identical to corresponding densities for the population of stellar companions in spectroscopic binaries. One possible explanation is that the majority of EPCs are indeed stellar companions viewed at very small inclination angles. In this contribution we show how such an interpretation may be consistent with the rest of the data. If the EPC are indeed planets, then the most interesting question stemming from our findings is why their orbital elements are distributed like those of the stellar companions.