2019A&A...631A.128C


Query : 2019A&A...631A.128C

2019A&A...631A.128C - Astronomy and Astrophysics, volume 631A, 128-128 (2019/11-1)

Multiple stellar populations in NGC 1866. New clues from Cepheids and colour-magnitude diagram.

COSTA G., GIRARDI L., BRESSAN A., CHEN Y., GOUDFROOIJ P., MARIGO P., RODRIGUES T.S. and LANZA A.

Abstract (from CDS):

We performed a comprehensive study of the stellar populations in the young Large Magellanic Cloud cluster NGC 1866, combining the analysis of its best-studied Cepheids with that of a very accurate colour-magnitude diagram (CMD) obtained from the most recent Hubble Space Telescope photometry. We used a Bayesian method based on new PARSEC stellar evolutionary tracks with overshooting and rotation to obtain ages and initial rotation velocities of five well-studied Cepheids of the cluster. We find that four of the five Cepheids belong to an initially slowly rotating young population (of 176±5Myr), while the fifth is significantly older, either 288±20Myr for models with high initial rotational velocity (ωi∼0.9), or 202±5Myr for slowly rotating models. The complementary analysis of the CMD rules out the latter solution while strongly supporting the presence of two distinct populations of ∼176Myr and ∼288Myr, respectively. Moreover, the observed multiple main sequences and the turn-offs indicate that the younger population is mainly made of slowly rotating stars, as is the case of the four younger Cepheids, while the older population is made mainly of initially fast rotating stars, as is the case of the fifth Cepheid. Our study reinforces the notion that some young clusters like NGC 1866 harbour multiple populations. This work also hints that the first population, i.e. the older, may inherit the angular momentum from the parent cloud while stars of the second population, i.e. the younger, do not.

Abstract Copyright: © ESO 2019

Journal keyword(s): Hertzsprung-Russell and C-M diagrams - stars: evolution - stars: rotation - stars: variables: Cepheids - galaxies: star clusters: individual: NGC 1866

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6564 1
2 NGC 1755 Cl* 04 55 16.390 -68 12 23.12   10.00 9.85     ~ 72 0
3 NGC 1844 Cl* 05 07 29.910 -67 19 26.86   12.29 12.08     ~ 45 0
4 NGC 1856 Cl* 05 09 30.290 -69 07 45.08   10.40 10.06     ~ 147 0
5 SV* HV 12197 Ce* 05 13 13 -65 30.8   16.741 16.102     ~ 28 0
6 SV* HV 12199 Ce* 05 13 19 -65 29.5   16.916 16.289     ~ 30 0
7 SV* HV 12198 cC* 05 13 26.6692125288 -65 27 04.932684468   16.627 15.970   15.230 ~ 40 0
8 NGC 1866 GlC 05 13 38.920 -65 27 52.75           ~ 407 0
9 MACHO 59.5436.172 Ce* 05 13 41.911 -65 27 59.98   16.696 16.54 16.02   ~ 13 0
10 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 16525 1
11 Cl* NGC 1866 WE 2 Ce* ~ ~           ~ 11 0

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2023.02.04-10:43:23

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