On the nature of the high-latitude B-type star CPD-6l °455

High-resolution, high-signal-to-noise optical and near-infrared spectra, along with lower resolution infrared spectra, of the high-latitude, faint B-type star CPD-61 °455 have been obtained using the 3.9-m Anglo-Australian Telescope. Using LTE model atmosphere codes to compute optical absorption profiles in the hot star, we find atmospheric parameters of Teff = 25 000 K and logg~3.6; furthermore, the abun-dance pattern of metals as measured differentially with respect to the Galactic disc B-type star eCMa is not that expected for a normal young object. We show that the previous interpretation of this object as a composite consisting of a B-type star with a possible early K-type giant secondary is consistent with the near-infrared and infrared data. We hypothesize that CPD-61°455 is in fact an evolved, post-asympto-tic giant branch (post-AGB) star in a binary system, and is possibly a hotter analogue of the binary systems containing younger, cooler post-AGB stars discussed by va