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J/A+A/503/545   Equivalent widths of Li, Na, Fe, Ca in NGC 6397    (Lind+, 2009)

Signatures of intrinsic Li depletion and Li-Na anti-correlation in the metal-poor globular cluster NGC 6397. Lind K., Primas F., Charbonnel C., Grundahl F., Asplund M. <Astron. Astrophys. 503, 545 (2009)> =2009A&A...503..545L
ADC_Keywords: Clusters, globular; Stars, late-type; Abundances; Atomic physics Keywords: stars: abundances - stars: late-type - line: formation Abstract: To alleviate the discrepancy between the prediction of the primordial lithium abundance in the universe and the abundances observed in Pop II dwarfs and subgiant stars, it has been suggested that the stars observable today have undergone photospheric depletion of lithium. To identify the cause of such depletion, it is important to accurately establish the behaviour of lithium abundance with effective temperature and evolutionary phase. Stars in globular clusters are ideal objects for such abundance analysis, as relative stellar parameters can be precisely determined. We conduct a homogeneous analysis of a very large sample of stars in the metal-poor globular cluster NGC 6397, covering well all evolutionary phases from below the main sequence turn-off to high up the red giant branch. Non-LTE Li abundances or abundance upper limits are obtained for all stars, and for a size-able sub-set of the targets also Na abundances are obtained. The sodium abundances are used to distinguish stars formed out of pristine material from stars formed out of material affected by pollution from a previous generation of more massive stars. The dwarfs, turn-off, and early subgiant stars in our sample form a thin abundance plateau, disrupted in the middle of the subgiant branch by the lithium dilution caused by the first dredge-up. A second steep abundance drop is seen at the luminosity of the red giant branch bump. The turn-off stars are more lithium-poor, by up to 0.1dex, than subgiants that have not yet undergone dredge-up. In addition, hotter dwarfs are slightly more lithium-poor than cooler dwarfs, which may be a signature of the so-called Li dip in the cluster, commonly seen among PopI stars. The feature is however weak. A considerably large spread in Na abundance confirms that NGC6397 has suffered from intra-cluster pollution in its infancy and a limited number of Na-enhanced and Li-deficient stars strongly contribute to form a significant anti-correlation between the abundances of Na and Li. It is nevertheless seen that lithium abundances are unaffected by relatively high degrees of pollution. Lithium abundance trends with effective temperature and stellar luminosity are compared to predictions from stellar structure models including atomic diffusion and ad-hoc turbulence below the convection zone. We confirm previous findings that some turbulence, with strict limits to its efficiency, is necessary to explain the observations. Description: The tables contain coordinates, photometry, derived stellar parameters, equivalent widths, and abundances for a large number of dwarfs, subgiant branch stars, and red giant branch stars in the metal-poor globular cluster NGC6397. All abundances are given in logarithmic units relative to hydrogen, according to A(x)=log(N(x)/N(H))+12, where N(x) is the number density of element x and N(H) the number density of hydrogen. Table 3 contains only a subset (32) of all targets. The oscillator strengths adopted are listed in the paper. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 129 517 Photometry and effective temperatures table3.dat 50 1907 Equivalent widths and Fe abundances for the UVES targets table4.dat 129 468 Adopted stellar parameters, equivalent widths and abundances of Li, Na, and Ca
See also: J/PASJ/57/45 : Lithium abundances of F-K stars (Takeda+, 2005) J/A+A/503/541 : Neutral Li in late-type stars non-LTE calculations (Lind+ 2009) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 7 I7 --- ID1 ? Identification number of target (1) 9- 15 I7 --- ID2 ? Identification number of target (2) 18- 19 I2 h RAh Right Ascension J2000, hours 22- 23 I2 min RAm Right Ascension J2000, minutes 25- 29 F5.2 s RAs Right Ascension J2000, seconds 31 A1 --- DE- Declination J2000, (sign) 32- 33 I2 deg DEd Declination J2000, degrees 36- 37 I2 arcmin DEm Declination J2000, arcminutes 39- 43 F5.2 arcsec DEs Declination J2000, arcseconds 46- 50 F5.1 km/s RV Barycentric radial velocity 53- 58 F6.3 mag Vmag Apparent visual magnitude 61- 65 F5.3 mag (b-y)0 ? Stroemgren colour (b-y) (3) 68- 72 F5.3 mag (v-y)0 ? Stroemgren colour (v-y) (3) 75- 79 F5.3 mag c0 ? Stroemgren colour c_1_ (3) 81- 84 I4 K T008 ? Effective temperature (O09) (4) 86- 89 I4 K TRM05 ? Effective temperature (RM05) (4) 91- 94 I4 K TA99 ? Effective temperature (A9699) (4) 96- 99 I4 K THa ? Effective temperature (Halpha) (4) 104 A1 --- Rem [abc] Remark (5) 106-129 A24 --- Com Comments
Note (1): Identification number, this paper Note (2): Identification number used by Gonzalez-Hernandez et al. (2009, submitted to A&A). Note (3): Corrected for reddening Note (4): Effective temperatures calculated using: O09 = Onehag et al. (2009, Cat. J/A+A/498/527) relations RM05 = Ramirez & Melendez (2005ApJ...626..465R) relations A9699 = Alonso et al. (1996A&A...313..873A, 1999A&AS..140..261A) relations Halpha = Hα-based temperatures Note (5): Flags as follows: a = Star observed in the H679.7 setting or in the H665.0 setting b = Star not observed in the H679.7 setting or in the H665.0 setting c = Disregarded star with comment
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 7 I7 --- ID1 ? Identification number of target 9- 11 A3 --- Ion [Fe1 Fe2] Element + ionisation stage 15- 22 F8.4 nm Lambda Wavelength of line 25- 29 F5.2 pm EW Equivalent width 33- 36 F4.2 pm e_EW Error on EW 40- 43 F4.2 [---] Abund Iron abundance (log scale, H=12) 47- 50 F4.2 [---] e_Abund Error on Abund
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 7 I7 --- ID1 ? Identification number of target 9- 15 I7 --- ID2 ? Identification number of target 18- 23 F6.3 mag VMAG Absolute visual magnitude 25- 28 I4 K Teff Adopted effective temperature (O09 scale) 30- 33 F4.2 [cm/s2] logg Surface gravity 35- 38 F4.2 km/s Vturb Microturbulence velocity 40- 44 F5.2 [solLum] logLum Logarithm of luminosity 46- 49 F4.2 pm W6707 Equivalent width of LiI 670.7nm line 51- 54 F4.2 pm e_W6707 Error on W6707 56 A1 --- l_ALi Limit flag on ALi (upper limit) 57- 60 F4.2 [---] ALi Lithium abundance 62- 65 F4.2 [---] e_ALi ?=- Error on ALi 67- 70 F4.2 pm W8183 Equivalent width of NaI 818.3nm line 72- 75 F4.2 pm e_W8183 Error on W8183 77- 81 F5.2 pm W8194 Equivalent width of NaI 819.4nm line 83- 86 F4.2 pm e_W8194 Error on W8194 88 A1 --- l_ANa Limit flag on ANa (upper limit) 89- 92 F4.2 [---] ANa Sodium abundance 94- 97 F4.2 [---] e_ANa ?=- Error on ANa 99-103 F5.2 pm W6122 ? Equivalent width of CaI 612.2nm line 105-108 F4.2 pm e_W6122 ? Error on W6122 110-114 F5.2 pm W6162 ? Equivalent width of CaI 616.2nm line 116-119 F4.2 pm e_W6162 ? Error on W6162 121-124 F4.2 [---] ACa ? Calcium abundance 126-129 F4.2 [---] e_ACa ? Error on ACa
Acknowledgements: Karin Lind, klind(at)eso.org
(End) Karin Lind [ESO, Germany], Patricia Vannier [CDS] 02-Sep-2009
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

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