A NIR spectral sequence of O-type supergiants.

FEDERICO GIUDICI MICHILINI; G. FERRERO; R. GAMEN; N. MORRELL; R. BARBÁ

Rosario

Congreso; Reunión anual de la Asociación Argentina de Astronomía; 2020

The study of spectral morphology is a powerful tool for understanding the fundamental propertiesof stars. The spectral classification scheme for O stars was revisited and a new set of spectral standard stars wasproposed for all sub-types between O2 and B0 and for all luminosity classes. We are working on the constructionof a spectral atlas with high quality observations between 0.85 − 2.5 μm. Observations for this project have begunseven years ago, and they are carried out with the GNIRS (Gemini Observatory) and FIRE (Las CampanasObservatory) spectrographs. We present here a second batch of results, including the spectra of a completetemperature sequence of supergiant standard stars in the J, H and K-bands. The analysis of this data set impliesthat it is possible to define spectral classification criteria using the He i and He ii lines present in it.