S128, AN HII and Star Forming Region in the Galactic Outback

Tapia, Mauricio; Bohigas, Joaquin
Referencia bibliográfica

Star Formation at High Angular Resolution, International Astronomical Union. Symposium no. 221, held 22-25 July, 2003 in Sydney, Australia, Poster meeting abstract

Fecha de publicación:
0
2003
Número de autores
2
Número de autores del IAC
0
Número de citas
0
Número de citas referidas
0
Descripción
Calibrated optical narrow-band imaging supplemented by near-infrared imaging of are Sh2-128 and Sh2-128N are presented. This region contains a developed H II region and a neighboring compact H II region associated with a pair of water maser sources. Midway between these the core of a CO cloud is located. Sh2-128 is an H II region at whose geometrical center lies its principal ionizing star. Slit spectroscopy was used for obtaining nebular line fluxes abundances and physical parameters of Sh2-128. The present JHKs images show the presence of several point sources and nebular emission knots with large near-infrared excesses in Sh2-128N. One red knot coincides with the compact H II region and a far-infrared emission peak. Star counts in J and Ks show a small cluster of B-type stars mainly in associated with Sh2-128N. Except for the youngest objects the stars in the whole region are moderately obscured. Our results sugegst that Sh2-128 and Sh2-128N constitute a single complex formed from the same molecular cloud but with ages around one million and 300000 years respectively. A new distance of 9.5 kpc is derived which implies a galactocentric distance of 13.5 kpc and z=550.