Discovery of the Pre-Main Sequence Population of the Stellar Association LH 95 in the Large Magellanic Cloud with Hubble Space Telescope ACS Observations

TL;DR

This study uses Hubble Space Telescope imaging to identify and analyze a large population of pre-main sequence stars in the LH 95 stellar association in the Large Magellanic Cloud, revealing detailed stellar demographics.

Contribution

First direct detection and detailed analysis of PMS stars in LH 95, extending understanding of stellar populations in LMC associations.

Findings

Over 2,500 PMS stars detected down to 0.3 solar masses

PMS stars are spatially clustered with higher mass stars

Stellar content spans from OB stars to faint PMS stars

Abstract

We report the discovery of an extraordinary number of pre-main sequence (PMS) stars in the vicinity of the stellar association LH 95 in the Large Magellanic Cloud (LMC). Using the {\em Advanced Camera for Surveys} on-board the {\em Hubble} Space Telescope in wide-field mode we obtained deep high-resolution imaging of the main body of the association and of a nearby representative LMC background field. These observations allowed us to construct the color-magnitude diagram (CMD) of the association in unprecedented detail, and to decontaminate the CMD for the average LMC stellar population. The most significant result is the direct detection of a substantial population of PMS stars and their clustering properties with respect to the distribution of the higher mass members of the association. Although LH 95 represents a rather modest star forming region, our photometry, with a detection limit $V$ \lsim 28 mag, reveals in its vicinity more than 2,500 PMS stars with masses down to $\sim 0.3$ M{\solar}. Our observations offer, thus, a new perspective of a typical LMC association: The stellar content of LH 95 is found to extend from bright OB stars to faint red PMS stars, suggesting a fully populated Initial Mass Function (IMF) from the massive blue giants down to the sub-solar mass regime.