| Issue |
A&A
Volume 675, July 2023
|
|
|---|---|---|
| Article Number | A203 | |
| Number of page(s) | 10 | |
| Section | Stellar structure and evolution | |
| DOI | https://doi.org/10.1051/0004-6361/202142838 | |
| Published online | 20 July 2023 | |
Photometric determination of the mass accretion rates of pre-main-sequence stars
VII. The low-density cluster NGC 376 in the Small Magellanic Cloud⋆,⋆⋆
1
Sterrewacht Leiden, PO Box 9513 2300 RA Leiden, The Netherlands
e-mail: tsilia@strw.leidenuniv.nl
2
European Space Research and Technology Centre, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands
e-mail: gdemarchi@esa.int
3
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
e-mail: panagia@stsci.edu
Received:
5
December
2021
Accepted:
8
December
2022
Aims. We study the properties of low-mass stars recently formed in the field of the NGC 376 cluster in the Small Magellanic Cloud (SMC).
Methods. Using photometric observations acquired with the Hubble Space Telescope (HST) in the V, I, and Hα bands, we identify 244 candidate pre-main-sequence (PMS) stars showing Hα excess emission at the 5σ level and with Hα equivalent width of 20 Å or more. We derive physical parameters for all PMS stars, including masses, ages, and mass accretion rates. We compare the effective mass accretion rate of stars in NGC 376 to that of objects in the NGC 346 cluster, with NGC 346 featuring similar metallicity but higher total mass and gas density.
Results. We find a median age of 28 Myr for this population (with 25th and 75th percentiles at about 20 and 40 Myr, respectively), in excellent agreement with previous studies of massive stars in the same field. The PMS stars are rather uniformly distributed across the field, whereas massive stars are more clustered. The spatial distribution of PMS objects is compatible with them having formed in the centre of the cluster and then migrating outwards. We find that in NGC 376 the mass accretion rate is systematically lower than in NGC 346 for stars of the same mass and age. This indicates that, in addition to metallicity, there are other environmental factors affecting the rate of mass accretion onto PMS stars. Our observations suggest that the gas density in the star-forming region might play a role.
Key words: stars: formation / stars: pre-main-sequence / Magellanic Clouds / galaxies: star clusters: individual: NGC 376 / open clusters and associations: individual: NGC 376
Full Table 2 is only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/675/A203
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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