We present a semi-empirical spectral classification scheme for normal B-type stars using near-infrared (NIR) spectra (1.5-1.7 μm) from the Sloan Digital Sky Survey Apache Point Observatory Galaxy Evolution Experiment (APOGEE2)-N data release 14 (DR14) database. The main motivation for working with B-type stars is their importance in the evolution of young stellar clusters; however, we also take advantage of having a numerous sample (316 stars) of B-type star candidates in APOGEE2-N, for which we also have optical (3600-9100 Å) counterparts from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. By first obtaining an accurate spectral classification of the sources using the LAMOST DR3 spectra and the canonical spectral classification scheme, we found a linear relation between optical spectral types and the equivalent widths of the hydrogen lines of the Brackett series in the APOGEE2-N NIR spectra. This relation extends smoothly from a similar relation for O and early B stars found by Roman-Lopes et al. This way, we obtain a catalog of B-type sources with features in both the optical and NIR and a classification scheme refined down to one spectral subclass.
|Original language||English (US)|
|State||Published - May 1 2020|
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
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APOGEE2-N NIR spectra of B-type stars
Ramírez-Preciado, V. G. (Contributor), Roman-Lopes, A. (Creator), Hernández, J. (Contributor), García-Hernández, D. A. (Contributor), Stassun, K. (Creator), Stringfellow, G. S. (Creator) & Kim, J. S. (Creator), Centre de Donnees Strasbourg (CDS), 2021
DOI: 10.26093/cds/vizier.18940005, https://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/894/5