New Young Star Candidates in CG4 and Sa101

TL;DR

This study identifies new young star candidates in the CG4 and Sa101 regions using infrared data from Spitzer, revealing their distribution and characteristics, and expanding the known population of young stars in this nebula area.

Contribution

The paper presents the discovery of 16 new young star candidates in CG4 and Sa101 using infrared observations, enhancing understanding of star formation in this region.

Findings

All previously known young stars show infrared excesses.

16 new young star candidates identified based on infrared excess.

Most new candidates are Class II objects, indicating a specific evolutionary stage.

Abstract

The CG4 and Sa101 regions together cover a region of ~0.5 square degree in the vicinity of a "cometary globule" that is part of the Gum Nebula. There are seven previously identified young stars in this region; we have searched for new young stars using mid- and far-infrared data (3.6 to 70 microns) from the Spitzer Space Telescope, combined with ground-based optical data and near-infrared data from the Two-Micron All-Sky Survey (2MASS). We find infrared excesses in all 6 of the previously identified young stars in our maps, and we identify 16 more candidate young stars based on apparent infrared excesses. Most (73%) of the new young stars are Class II objects. There is a tighter grouping of young stars and young star candidates in the Sa101 region, in contrast to the CG4 region, where there are fewer young stars and young star candidates, and they are more dispersed. Few likely young objects are found in the "fingers" of the dust being disturbed by the ionization front from the heart of the Gum Nebula.