Near infra-red and optical spectroscopy of Delta Scorpii

Abstract

Spectroscopic observations of δ Sco in the near IR and optical wavelengths, obtained shortly after its recent periastron passage are reported. The IR spectra are dominated by the HI Paschen and Brackett lines. An IR excess is seen which can be attributed to free-free emission from a circumstellar shell. The observed Paschen and Brackett line intensities deviate significantly from Case B predictions and indicate optical depth effects. These effects are modeled. The overall spectral behaviour of δ Sco at present is that of a typical Be star.