Deep wide-field near-infrared survey of the Carina Nebula

TL;DR

This study presents a deep near-infrared survey of the Carina Nebula using HAWK-I at the ESO VLT, revealing the low-mass stellar population, disk dispersal timescales, and jet activity, supporting triggered star formation by ionization fronts.

Contribution

It provides the first comprehensive near-infrared survey of Carina's low-mass stars, confirming the initial mass function and disk evolution influenced by massive star feedback.

Findings

Approximately 3200 stars with masses >= 1 Msun identified.

Lower near-infrared excess fractions indicate faster disk dispersal.

Six molecular hydrogen jets detected, supporting triggered star formation scenario.

Abstract

(abbreviated) We used HAWK-I at the ESO VLT to produce a near-infrared survey of the Carina Nebula that is deep enough to detect the full low-mass stellar population. The results of a recent deep X-ray survey are used to distinguish between young stars in Carina and background contaminants. We find that the ages of the low-mass stars (derived from color-magnitude diagrams of the invidual cluster in the Carina Nebula) agree with previous age estimates for the massive stars. About 3200 of the X-ray selected stars have masses >= 1 Msun; this number is in good agreement with extrapolations of the field IMF based on the number of high-mass stars and shows that there is no deficit of low-mass stars. The near-infrared excess fractions for the stellar populations in Carina are lower than typical for other, less massive clusters of similar age, suggesting a faster timescale of circumstellar disk dispersal than in the more quiescent regions, most likely due to the very high level of massive star feedback. Narrow-band images reveal six molecular hydrogen jets. However, none of the optical HH objects shows molecular hydrogen emission, suggesting that the jet-driving protostars are located very close to the edges of the globules in which they are embedded. This adds strong support to the scenario that their formation was triggered by the advancing ionization fronts.