Early-type PMS and MS objects in M16 and the Carina star-forming regions

TL;DR

This study utilizes multi-facility wide-angle observations to identify and classify early-type pre-main sequence and main sequence stars in star-forming regions like M16 and Carina, revealing their properties and evolutionary stages.

Contribution

It introduces a comprehensive method combining optical and infrared data to distinguish and classify early-type stars, including new Herbig Be/Ae stars, in large star-forming regions.

Findings

Discovery of new Herbig Be/Ae stars.

Analysis of rotational velocity evolution from pre-main to main sequence.

Effective discrimination between circumstellar and interstellar emission lines.

Abstract

Thanks to a variety of pertinent wide-angle facilities (WFI-slitless mode, VLT-FLAMES (Pasquini et al. 2002), SPITZER, 2MASS) it is possible to comprehensively study the nature of early-type objects in star-forming regions like the Eagle Nebula and Carina on large spatial scales. In them, the young open clusters NGC 6611, Trumpler 14, Trumpler 15, Trumpler 16, and their vicinities are of particular interest. With the WFI in its slitless mode (Baade et al. 1999), one can reliably and with little extra effort discriminate in thousands of spectra between intrinsic circumstellar emission as in HBe/Ae stars and diffuse interstellar line emission. The only bias results from the need of the equivalent width and absolute strength of the line emission to be sufficient for detection. VLT-FLAMES spectra combined with infrared data from SPITZER and 2MASS permit the nature of the objects with and without emission-lines to be derived. Following this approach, we report on the discovery and classification of new Herbig Be/Ae stars, pre-main sequence objects, and main sequence stars in these regions. Based on line-width measurements in VLT-FLAMES spectra, the evolution of the rotational velocities between pre-main sequence and main sequence phases is also discussed.