A photometric and spectroscopic investigation of star formation in the very young open cluster NGC6383

TL;DR

This study combines photometric and spectroscopic data to analyze the properties and distribution of pre-main-sequence stars in the young open cluster NGC 6383, revealing a complex and contaminated stellar population.

Contribution

It provides a detailed characterization of low-mass PMS stars in NGC 6383 using combined photometric and spectroscopic observations, highlighting their age, extinction, and spatial distribution.

Findings

PMS stars are likely coeval with the cluster's O-star binary HD 159176.

Detected a wide range of extinction among objects, up to A_V=20.

H-alpha emitters show complex spatial distribution with contamination from foreground/background stars.

Abstract

The very young open cluster NGC 6383 centered on the O-star binary HD 159176 is an interesting place for studying the impact of early-type stars with strong radiation fields and powerful winds on the formation processes of low-mass stars. To investigate this process, it is necessary to determine the characteristics (age, presence, or absence of circumstellar material) of the population of low-mass pre-main-sequence (PMS) stars in the cluster. We obtained deep U B V (R I)_c H-alpha photometric data of the entire cluster as well as medium-resolution optical spectroscopy of a subsample of X-ray selected objects. Our spectroscopic data reveal only very weak H-alpha emission lines in a few X-ray selected PMS candidates. We photometrically identify a number of H-alpha emission candidates but their cluster membership is uncertain. We find that the fainter objects in the field of view have a wide range of extinction (up to A_V = 20), one X-ray selected OB star having A_V ~ 8. Our investigation uncovers a population of PMS stars in NGC 6383 that are probably coeval with HD 159176. In addition, we detect a population of reddened objects that are probably located at different depths within the natal molecular cloud of the cluster. Finally, we identify a rather complex spatial distribution of H-alpha emitters, which is probably indicative of a severe contamination by foreground and background stars.