A study of the Galactic plane towards l = 305

TL;DR

This study provides new optical observations of the Galactic plane near l=305°, revealing high extinction, abnormal reddening laws, and revised parameters for nearby clusters, contributing to understanding the Galaxy's spiral structure.

Contribution

It introduces new photometric data and analysis methods to determine fundamental parameters of clusters and stars in a complex Galactic region with abnormal extinction laws.

Findings

High interstellar absorption ($A_V \\sim 10$) detected.

Abnormal extinction law identified in the line of sight.

Clusters appear closer than previously estimated.

Abstract

We present optical ($UBVI_C$) observations of a rich and complex field in the Galactic plane towards $l \sim 305^{\circ}$ and $b \sim 0^{\circ}$. Our analysis reveals a significantly high interstellar absorbtion ($A_V \sim 10$) and an abnormal extinction law in this line of sight. Availing a considerable number of color combinations, the photometric diagrams allow us to derive new estimates of the fundamental parameters of the two open clusters Danks~1 and Danks~2. Due to the derived abnormal reddening law in this line of sight, both clusters appear much closer (to the Sun) than previously thought. % Additionally, we present the optical colors and magnitudes of the WR~48a star and its main parameters were estimated. The properties of the two embedded clusters DBS2003~130 and 131, are also addressed. We identify a number of Young Stellar Objects which are probable members of these clusters. This new material is then used to revisit the spiral structure in this sector of the Galaxy showing evidence of populations associated with the inner Galaxy Scutum-Crux arm.