Near-infrared Spectra of a Sample of Galactic Unclassified B[e] Stars

ARIAS, MARÍA L.; CIDALE, LYDIA S.; KRAUS, MICHAA; TORRES, ANDREA F.; AIDELMAN, YAEL; ZOREC, JUAN; GRANADA, ANAHÍ

PUBL. ASTRON. SOC. PAC.

IOP Publishing

Lugar: Bristol; Año: 2018 vol. 130

0004-6280

B[e] stars are surrounded by cool and dense circumstellar environmentswhere molecules and dust are formed. These stars are rare and displaycomplex spectra whose photospheric features are frequently veiled bytheir circumstellar envelopes, making it difficult to assign themspectral types and evolutionary phases. On the basis of a detailedanalysis of medium-resolution spectra in the near-infrared region,together with optical observations and available data from astronomicaldatabases, we attempt to improve their spectral classification and inferthe properties of their circumstellar environments. To this aim, we haveselected a group of five bright IRAS sources (IRAS 02155+6410, MWC 728,AS 119, MWC 819, and IRAS 07080+0605): one star with large infraredexcess and four unclassified B[e] stars or FS CMa stars, most of whichhave been poorly studied. We present and describe our observations anddiscuss possible classifications of the sample objects. For all stars,medium-resolution spectra in the region of 2.17?2.39 μm and inthe L band are shown for the first time. Infrared features, such as theabsorption molecular CO bands and metallic lines, reveal the presence ofa late-type companion in MWC 728, and suggest the possible binary naturein AS 119. IRAS 07080+0605 shows evidence of a surrounding cool COmolecular cloud. CS molecular emission may be present in MWC 819 L-bandspectra. We suggest that this object is a protoplanetary nebulae.