2009A&A...505..727D


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.28CET07:24:07

2009A&A...505..727D - Astronomy and Astrophysics, volume 505, 727-733 (2009/10-2)

CNO enrichment by rotating AGB stars in globular clusters.

DECRESSIN T., CHARBONNEL C., SIESS L., PALACIOS A., MEYNET G. and GEORGY C.

Abstract (from CDS):

AGB stars have long been held responsible for the important star-to-star variations in light elements observed in Galactic globular clusters (GCs). We analyse the main impacts of a first generation of rotating intermediate-mass stars on the chemical properties of second-generation GC stars. The rotating models were computed without magnetic fields and without the effects of internal gravity waves. They account for the transports by meridional currents and turbulence. We computed the evolution of both standard and rotating stellar models with initial masses between 2.5 and 8M within the metallicity range covered by Galactic GCs. During central He-burning, rotational mixing transports fresh CO-rich material from the core towards the hydrogen-burning shell, leading to the production of primary 14N. In stars more massive than M>4M, the convective envelope reaches this reservoir during the second dredge-up episode, resulting in a large increase in the total C+N+O content at the stellar surface and in the stellar wind. The corresponding pollution depends on the initial metallicity. At low- and intermediate-metallicity (i.e., [Fe/H] lower than or equal to ~-1.2), it is at odds with the constancy of C+N+O observed among GC low-mass stars. With the given input physics, our models suggest that massive (i.e., ≥4M) rotating AGB stars have not shaped the abundance patterns observed in low- and intermediate-metallicity GCs. Our non-rotating models, on the other hand, do not predict surface C+N+O enhancements, hence are in a better position as sources of the chemical anomalies in GCs showing the constancy of the C+N+O. However at the moment, there is no reason to think that intermediate-mass stars were not rotating. On the contrary there is observational evidence that stars in clusters have higher rotational velocities than in the field.

Abstract Copyright:

Journal keyword(s): stars: AGB and post-AGB - star: rotation - star: abundances - globular clusters: general

Simbad objects: 16

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Number of rows : 16

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NGC 104 GlC 00 24 05.359 -72 04 53.20   5.78 4.09     ~ 3575 0
2 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9560 1
3 NGC 288 GlC 00 52 45.24 -26 34 57.4   10 8.13     ~ 931 0
4 NGC 362 GlC 01 03 14.26 -70 50 55.6     6.58     ~ 945 0
5 NGC 1851 GlC 05 14 06.76 -40 02 47.6   8.80 7.23     ~ 1252 0
6 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14993 1
7 NGC 2004 Cl* 05 30 41.340 -67 17 21.83   9.6       ~ 265 0
8 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3032 0
9 M 3 GlC 13 42 11.62 +28 22 38.2     6.39     ~ 2277 0
10 M 13 GlC 16 41 41.634 +36 27 40.75     5.8     ~ 2016 0
11 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 1916 0
12 NGC 6397 GlC 17 40 42.09 -53 40 27.6   7.39 5.17     ~ 1808 1
13 NGC 6712 GlC 18 53 04.32 -08 42 21.5   9.85 8.69     ~ 470 0
14 NGC 6752 GlC 19 10 52.11 -59 59 04.4   6.96 6.28     ~ 1817 0
15 V* RR Lyr RR* 19 25 27.9123232234 +42 47 03.690634101   7.36   7.6   A8-F7 883 0
16 M 15 GlC 21 29 58.33 +12 10 01.2   3       ~ 2923 0

    Equat.    Gal    SGal    Ecl

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2020.10.28-07:24:07

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