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We present a semi-empirical spectral classification scheme for normal B-typestars using near-infrared spectra (1.5-1.7 $\mu$m) from the SDSS APOGEE2-N DR14database. The main motivation for working with B-type stars is their importancein the evolution of young stellar clusters, however we also take advantage ofhaving a numerous sample (316 stars) of B-type star candidates in APOGEE2-N,for which we also have optical (3600-9100 \angstrom) counterparts from theLAMOST survey. By first obtaining an accurate spectral classification of thesources using the LAMOST DR3 spectra and the canonical spectral classificationscheme Gray & Corbally 2009, we found a linear relation between opticalspectral types and the equivalent widths of the hydrogen lines of the Brackettseries in the APOGEE2-N NIR spectra. This relation extends smoothly from asimilar relation for O and early-B stars found by Roman-Lopes et al. (2018).This way, we obtain a catalog of B-type sources with features in both theoptical and NIR, and a classification scheme refined down to one spectralsub-class.

Spectral classification of B stars: The empirical sequence using SDSS-IV/APOGEE near-IR data