Multiple stellar populations in Magellanic Cloud clusters. II. Evidence also in the young NGC1844?

TL;DR

This study investigates the young LMC cluster NGC1844 using HST data, revealing a broad main sequence likely caused by factors such as stellar rotation or binaries, but not solely due to age or chemical variations.

Contribution

The paper provides new evidence of main sequence broadening in a young cluster, exploring potential causes beyond age and chemical differences.

Findings

Main sequence shows intrinsic breadth not explained by errors or reddening.

Binary fraction and mass ratio distribution estimated.

Stellar rotation and binaries considered as possible causes.

Abstract

We use HST observations to study the LMC's young cluster NGC1844. We estimate the fraction and the mass-ratio distribution of photometric binaries and report that the main sequence presents an intrinsic breadth which can not be explained in terms of photometric errors only, and is unlikely due to differential reddening. We attempt some interpretation of this feature, including stellar rotation, binary stars, and the presence of multiple stellar populations with different age, metallicity, helium, or C+N+O abundance. Although we exclude age, helium, and C+N+O variations to be responsible of the main-sequence spread none of the other interpretations is conclusive.