Pre-main Sequence stars in LH91

Abstract

We study the accretion properties of pre-main sequence low-mass stars in the LH 91 association within the Large Magellanic Clouds. Using optical multiband photometry obtained with the Hubble Space Telescope, we identify 75 candidates showing H$\alpha$ excess emission above the 3$\sigma$ level with equivalent width $E{W}_{H\alpha }$ $\ge$ 10 Å. We estimate the physical parameters (effective temperature, luminosity, age, mass, accretion luminosity and mass accretion rate) of the pre-main sequence stellar candidates. The age distribution suggests a star formation ranging from few Myr up to $\sim$ 60 Myr with a gap between $\sim$ 5 Myr and 10 Myr. The masses of the PMS candidates span from 0.2 $M_{\odot }$ for the cooler objects to 1.0 $M_{\odot }$ with a median of $\sim$ 0.80 $M_{\odot }$. The median value of the accretion luminosity of our 75 PMS stars is about 0.12 $L_{\odot }$, the median value of the mass accretion rate is about 4.8 $\times$ $10^{-9}$ $M_{\odot }y{r}^{-1}$ with higher values for the younger population ($\sim$ 1.2 $\times$ $10^{-8}$ $M_{\odot }y{r}^{-1}$), and lower values for the older candidates ($\sim$ 4.7 $\times$ $10^{-9}$ $M_{\odot }y{r}^{-1}$). We compare our results with the findings on LH 95, the closer region to LH 91 for which accretion properties of PMS candidates were derived. An interesting qualitative outcome is that LH 91 seems to be in a more evolved stage. Moreover, we find that the PMS candidates are distributed homogeneously, without any evidence of clumps around more massive stars.

arXiv commentA&A, 2022

References in corpus (18)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• Very Low Mass Stars and Brown Dwarfs in Taurus-Auriga
• Photometric determination of the mass accretion rates of pre-main sequence stars. I. Method and application to the SN1987A field
• Progressive star formation in the young galactic super star cluster NGC 3603
• U-band study of the accretion properties in the sigma Ori star-forming region
• Photometric determination of the mass accretion rates of pre-main sequence stars. II. NGC346 in the Small Magellanic Cloud
• Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy. IV. The Large Magellanic Cloud: $\alpha$, Fe-peak, Light, and Heavy Elements
• The Complete Initial Mass Function Down to the Sub-Solar Regime in the Large Magellanic Cloud with Hubble Space Telescope ACS Observations
• The extinction law inside the 30 Doradus nebula
• The Resolved Distributions of Dust Mass and Temperature in Local Group Galaxies
• Photometric determination of the mass accretion rate of pre-main sequence stars. IV. Recent star formation in NGC 602
• Photometric determination of the mass accretion rates of pre-main sequence stars. V. Recent star formation in the 30 Dor nebula
• Low-Mass Pre-Main Sequence Stars in the Large Magellanic Cloud - III: Accretion Rates from HST-WFPC2 Observations
• Star Formation Around Supergiant Shells in the LMC
• Photometric determination of the mass accretion rates of pre-main sequence stars. VI. The case of LH 95 in the Large Magellanic Cloud
• A High-Resolution Multiband Survey of Westerlund 2 With the Hubble Space Telescope. II. Mass accretion in the Pre-Main Sequence Population
• Mass accretion rates from multi-band photometry in the Carina Nebula: the case of Trumpler 14

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