Sh2-173 and its environs: a hierarchical system of three generations?

CICHOWOLSKI, S.; ROMERO, G.A.; ORTEGA, M.; CAPPA, C.E.; VASQUEZ, J.

San Juan, Argentina

Congreso; Reunión anual 2008 de la AAA; 2008

Asoc. Argentina de Astronomía

We present a multiwavelength atudy of the interstellar medium around the HII region Sh2-173. the ionized region is clearly detected in the optical, in the radio continuum, and in the IR images. Sh2-173 presents a stratified structure: the ionized gas is partially bordered by a photodissociation region (PDR), which in turn, is encircled by a molecular structure. Based on  different color criteria and using the available infrared point source catalogues, we have identified 46 YSO candidates located onto the molecular gas associated with Sh2-173. On the other hand, Sh2-173 is located in a dense edge of a large HI shell. Based on age estimates of the different structures we concluded that Sh2-173 may be part of a hierarchical system of three generations.