Access to Astronomical Catalogues

← Click to display the menu
J/A+A/533/A69      Spectroscopy of 124 RGB stars in NGC 1851   (Carretta+, 2011)

Multiple stellar populations in the globular cluster NGC 1851 Carretta E., Lucatello S., Gratton R., Bragaglia A, D'Orazi V. <Astron. Astrophys. 533, A69 (2011)> =2011A&A...533A..69C
ADC_Keywords: Clusters, globular ; Stars, giant; Stars, population II ; Radial velocities ; Effective temperatures ; Abundances Keywords: stars: abundances - stars: atmospheres - globular clusters: general - globular clusters: individual: NGC 1851 - stars: Population II Abstract: We present a detailed chemical tagging of individual stellar populations in the Galactic globular cluster (GC) NGC 1851. Abundances are derived from FLAMES spectra for the largest sample of giants (124) and the widest number of elements ever analysed in this peculiar GC. The chemistry is characterised using homogeneous abundances of proton-capture (O, Na, Mg, Al, Si), α-capture (Ca, Ti), Fe-peak (Sc, V, Mn, Co, Ni, Cu), and neutron-capture elements (Y, Zr, Ba, La, Ce, Nd, Eu, Dy). We confirm the presence of an [Fe/H] spread larger than the observational errors in this cluster, but too small to clearly separate different sub-populations. We instead propose a classification scheme using a combination of Fe and Ba (which is much more abundant in the more metal-rich group) by means of a cluster analysis. With this approach, we separated stars into two components of a metal-rich (MR) and a metal-poor (MP) population. Each component displays a Na-O anticorrelation, which is a signature of a genuine GC, but has different ratios of primordial (FG) to polluted (SG) stars. Moreover, clear (anti)correlations of Mg and Si with Na and O are found for each component. The level of [α/H] tracks iron and is higher in the MR population, which might therefore have received an additional contribution from core-collapse supernovae. When considering all s-process elements, the MR population shows a larger enrichment than the MP one. This is probably due to the contribution of intermediate-low mass stars, because we find that the level of heavy s-process elements is higher than that of light s-process nuclei in the MR stars; however, a large contribution from low mass stars is unlikely, because it would likely cancel the O-Na anticorrelation. Finally, we confirm the presence of correlations between the amount of proton-capture elements and the level of s-process elements previously found by other investigations, at least for the MR population. This finding apparently requires a quite long delay for the second generation of the MR component. Scenarios for the formation of NGC 1851 appear complex, and are not yet well understood. A merger of two distinct GCs in a parent dwarf galaxy, each cluster with a different Ba level and an age difference of ∼1Gyr, might explain (i) the double subgiant branch, (ii) a possible difference in C content between the two original GCs, and (iii) the Stromgren photometry of this peculiar cluster. However, the correlation existing between p-capture and n-capture elements within the MR population requires the additional assumption of a long delay for its second generation. More observations are required to fully understand the formation of this GC. Description: For a sample of 124 RGB stars in NGC 1851 observed with FLAMES we present abundances of Fe, O, Na, Mg, Al, Si, Ca, Ti, Sc, V, Mn, Co, Ni, Cu, Y, Zr, Ba, La, Ce, Nd, Eu, Dy. n-capture elements (except Ba) are available only for the 13 stars observed with UVES-FLAMES. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 68 124 Identification, positions, B, V, K, RV, flag table3.dat 58 124 Teff, logg, [A/H], Vt, [Fe/H]I, [Fe/H]II table4.dat 61 124 [O/Fe], [Na/Fe], [Mg/Fe], [Al/Fe] table5.dat 55 124 [Si/Fe], [Ca/Fe], [Ti/Fe] I & II table6.dat 97 124 [Sc/Fe], [V/Fe], [Cr/Fe], [Mn/Fe], [Co/Fe], [Ni/Fe], [Cu/Fe] table7.dat 96 13 [Y/Fe], [Zr/Fe], [La/Fe], [Ce/Fe]. [Nd/Fe], [Eu/Fe], [Dy/Fe] table8.dat 18 124 [Ba/Fe]
See Also: J/PASP/104/1063 : BV Color-Magnitude Diagram for NGC 1851 (Walker 1992) J/A+A/333/479 : NGC1851 dynamical and evolutionary properties (Saviane+ 1998) J/A+A/525/A148 : Radial velocities in two globular clusters (Scarpa+, 2011) J/AJ/122/2569 : VI photometry of NGC 288, 362 and 1851 (Bellazzini+, 2001) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7 I1 h RAh Right ascension (J2000.0) 9- 10 I2 min RAm Right ascension (J2000.0) 12- 17 F6.3 s RAs Right ascension (J2000.0) 19 A1 --- DE- Declination sign (J2000.0) 20- 21 I2 deg DEd Declination (J2000.0) 23- 24 I2 arcmin DEm Declination (J2000.0) 26- 30 F5.2 arcsec DEs Declination (J2000.0) 32- 37 F6.3 mag Bmag B magnitude 39- 44 F6.3 mag Vmag V magnitude 46- 51 F6.3 mag Kmag K magnitude (2MASS) 53- 58 F6.2 km/s RV Heliocentric radial velocity 60- 68 A9 --- Inst Intrument: UVES, Giraffe-HR11, or Giraffe-HR13
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7- 10 I4 K Teff Effective temperature 12- 15 F4.2 [cm/s2] logg Gravity 17- 21 F5.2 [Sun] [A/H] Metallicity 23- 26 F4.2 km/s vt Microturbulent velocity ξ 28- 29 I2 --- o_[Fe/H]1 Number of FeI lines 31- 36 F6.3 [Sun] [Fe/H]1 Iron I abundance 38- 42 F5.3 [Sun] e_[Fe/H]1 Error on [Fe/H]1 44- 45 I2 --- o_[Fe/H]2 ? Number of FeII lines 47- 52 F6.3 [Sun] [Fe/H]2 ? Iron II abundance 54- 58 F5.3 [Sun] e_[Fe/H]2 ? Error on [Fe/H]2
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7 I1 --- o_[O/Fe] ? Number of O lines 9- 13 F5.2 [Sun] [O/Fe] ? Oxygen abundance 15- 18 F4.2 [Sun] e_[O/Fe] ? rms uncertainty on [O/Fe] 20 I1 --- o_[Na/Fe] ? Number of Na lines 22- 26 F5.2 [Sun] [Na/Fe] ? Sodium abundance 28- 31 F4.2 [Sun] e_[Na/Fe] ? rms uncertainty on [Na/Fe] 33 I1 --- o_[Mg/Fe] ? Number of Mg lines 35- 39 F5.2 [Sun] [Mg/Fe] ? Magnesium abundance 41- 44 F4.2 [Sun] e_[Mg/Fe] ? rms uncertainty on [Mg/Fe] 46 I1 --- o_[Al/Fe] ? Number of Al lines 48- 52 F5.2 [Sun] [Al/Fe] ? Aluminum abundance 54- 57 F4.2 [Sun] e_[Al/Fe] ? rms uncertainty on [Al/Fe] 59 A1 --- l_[O/Fe] [0,1] 0 = upper limit in [O/Fe] 61 A1 --- l_[Al/Fe] [0,1]? 0 = upper limit in [Al/Fe]
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7- 8 I2 --- o_[Si/Fe] ? Number of Si lines 10- 14 F5.2 [Sun] [Si/Fe] ? Silicon abundance 16- 19 F4.2 [Sun] e_[Si/Fe] ? rms uncertainty on [Si/Fe] 21- 22 I2 --- o_[Ca/Fe] ? Number of Ca lines 24- 28 F5.2 [Sun] [Ca/Fe] ? Calcium abundance 30- 33 F4.2 [Sun] e_[Ca/Fe] ? rms uncertainty on [Ca/Fe] 35- 36 I2 --- o_[Ti/Fe]1 ? Number of Ti I lines 38- 42 F5.2 [Sun] [Ti/Fe]1 ? Titanium I abundance 44- 47 F4.2 [Sun] e_[Ti/Fe]1 ? rms uncertainty on [Si/Fe] 49 I1 --- o_[Ti/Fe]2 ? Number of Ti II lines 51- 55 F5.2 [Sun] [Ti/Fe]2 ? Titanium II abundance
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7 I1 --- o_[Sc/Fe] Number of Sc lines 9- 13 F5.2 [Sun] [Sc/Fe] Scandium abundance 15- 18 F4.2 [Sun] e_[Sc/Fe] ? rms uncertainty on [Sc/Fe] 20 I1 --- o_[V/Fe] ? Number of V lines 22- 26 F5.2 [Sun] [V/Fe] ? Vanadium abundance 28- 31 F4.2 [Sun] e_[V/Fe] ? rms uncertainty on [V/Fe] 33 I1 --- o_[Cr/Fe] ? Number of Cr lines 35- 39 F5.2 [Sun] [Cr/Fe] ? Cromium abundance 41- 44 F4.2 [Sun] e_[Cr/Fe] ? rms uncertainty on [Cr/Fe] 46 I1 --- o_[Mn/Fe] ? Number of Mn lines 48- 52 F5.2 [Sun] [Mn/Fe] ? Manganese abundance 54- 57 F4.2 [Sun] e_[Mn/Fe] ? rms uncertainty on [Mn/Fe] 59 I1 --- o_[Co/Fe] ? Number of Co lines 61- 65 F5.2 [Sun] [Co/Fe] ? Cobalt abundance 67- 70 F4.2 [Sun] e_[Co/Fe] ? rms uncertainty on [Co/Fe] 72- 73 I2 --- o_[Ni/Fe] ? Number of Ni lines 75- 79 F5.2 [Sun] [Ni/Fe] ? Nichel abundance 81- 84 F4.2 [Sun] e_[Ni/Fe] ? rms uncertainty on [Ni/Fe] 86 I1 --- o_[Cu/Fe] ? Number of Cu lines 88- 92 F5.2 [Sun] [Cu/Fe] ? Copper abundance 94- 97 F4.2 [Sun] e_[Cu/Fe] ? rms uncertainty on [Cu/Fe]
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7 I1 --- o_[Y/Fe] ? Number of Y II lines 9- 13 F5.2 [Sun] [Y/Fe] ? Yttrium abundance 15- 18 F4.2 [Sun] e_[Y/Fe] ? rms uncertainty on [Y/Fe] 20 I1 --- o_[Zr/Fe] ? Number of Zr II lines 22- 26 F5.2 [Sun] [Zr/Fe] ? Zirconium abundance 28- 31 F4.2 [Sun] e_[Zr/Fe] ? rms uncertainty on [Zr/Fe] 33 I1 --- o_[La/Fe] ? Number of La II lines 35- 39 F5.2 [Sun] [La/Fe] ? Lanthanum abundance 41- 44 F4.2 [Sun] e_[La/Fe] ? rms uncertainty on [La/Fe] 46 I1 --- o_[Ce/Fe] ? Number of Ce II lines 48- 52 F5.2 [Sun] [Ce/Fe] ? Cerium abundance 54- 57 F4.2 [Sun] e_[Ce/Fe] ? rms uncertainty on [Ce/Fe] 59 I1 --- o_[Nd/Fe] ? Number of Nd II lines 61- 65 F5.2 [Sun] [Nd/Fe] ? Neodimium abundance 67- 70 F4.2 [Sun] e_[Nd/Fe] ? rms uncertainty on [Nd/Fe] 72 I1 --- o_[Eu/Fe] ? Number of Eu II lines 74- 78 F5.2 [Sun] [Eu/Fe] ? Europium abundance 80- 83 F4.2 [Sun] e_[Eu/Fe] ? rms uncertainty on [Eu/Fe] 85 I1 --- o_[Dy/Fe] ? Number of Dy II lines 87- 91 F5.2 [Sun] [Dy/Fe] ? Dysprosium abundance 93- 96 F4.2 [Sun] e_[Dy/Fe] ? rms uncertainty on [Dy/Fe]
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 5 I5 --- ID Identification number 7 I1 --- o_[Ba/Fe] ? Number of Ba II lines 9- 13 F5.2 [Sun] [Ba/Fe] ? Barium abundance 15- 18 F4.2 [Sun] e_[Ba/Fe] ? rms uncertainty on [Ba/Fe]
Acknowledgements: Eugenio Carretta, eugenio.carretta(at)oabo.inaf.it
(End) Francois Ochsenbein [CDS] 28-Jul-2011
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

catalogue service

© UDS/CNRS

Contact