Stellar contents and Star Formation in IRAS 18456-0223

Abstract

We use various analytical techniques to study Young Stellar Objects (YSOs) in an area of approximately $10' \times 10'$ in the IRAS 18456-0223 star-forming region. We use archival optical (Gaia DR3) and infrared (2MASS, UKIDSS, Spitzer, WISE, and Herschel) data, along with our optical spectroscopy of three bright stars for this purpose. We identify 89 YSOs (80 Class II and 9 Class I) based on their infrared properties. Our multiwavelength SED fits of selected YSOs show that they have masses $\sim 0.1$--$7.2$ $M_\odot$ and are up to $4$ Myr old. Our Minimum Spanning Tree (MST) analysis shows that these YSOs, situated at around 600 pc, form clusters with radial extents of order 0.5 pc and mean surface densities of $\sim 60$ pc$^{-2}$. We compare UKIDSS and 2MASS data of the YSOs and find that some of them show variability. We construct maps based on Herschel data which reveal multiple column density peaks ($N_{\rm H_2} \sim 10^{22}$ cm$^{-2}$) embedded in cold ($T_d \sim 10$--$13$ K) filaments. Our near-infrared extinction map exhibits several high-$A_V$ peaks, some of which coincide with the sub-mm column density maxima. Using our optical spectra of three bright sources, we show that they are of A--K spectral type. One star shows the Li I 6707 \r{A} line, indicating its youth.