Near- And Mid-Infrared Imaging Study of Young Stellar Objects around LkH$\alpha$ 234

TL;DR

This study uses high-resolution near- and mid-infrared imaging to identify and analyze young stellar objects around LkHα 234, revealing their structures, potential companions, and illuminating sources in detail.

Contribution

It provides detailed infrared observations of the LkHα 234 region, identifying new YSO candidates and clarifying their roles and relationships in the star-forming environment.

Findings

Eight YSO candidates detected around LkHα 234.

NW1 likely illuminates the reflection nebula and is a B6-7 type YSO.

Discovery of potential lower-mass companions F and G.

Abstract

We present high-resolution ($0\farcs2$) near-infrared images of the area surrounding the Herbig Be star LkH$\alpha$ 234 taken with the Coronagraphic Imager with Adaptive Optics (CIAO) and the adaptive optics on the Subaru Telescope. The near-infrared ($J$, $H$, $K$, $L'$ and $M'$ bands) images reveal circumstellar structures around LkH$\alpha$ 234 in detail. Eight young stellar object (YSO) candidates (Object B, C, D, E, F, G, NW1, and NW2) were detected at 2$\arcsec$--11$\arcsec$ from LkH$\alpha$ 234. Objects B and C are likely variable stars, which is consistent with a young evolutionary status. Three objects (LkH$\alpha$ 234, NW1, and NW2) were identified in the 11.8 $\micron$ (SiC) and 17.65 $\micron$ images obtained with the Long Wavelength Spectrometer (LWS) on the Keck Telescope. NW1 and NW2 are thought to be embedded young stars. We suggest that NW1 and not LkH$\alpha$ 234 is the source illuminating the reflection nebula west of LkH$\alpha$ 234, although Object G may be another candidate. In our images, these objects are located at the center of the 2 $\micron$ polarization, and NW1 resides at the center of a monopolar cavity. The SED of NW1 suggests that it is a YSO with a spectral type of B6--7. Object F and G were discovered by our observations at $1\farcs9$ and $2\farcs3$, respectively, from LkH$\alpha$ 234, and their proximity to LkH$\alpha$ 234 suggests that they may be its lower-mass companions.