New f-values in neutral lead obtained by time-resolved laser spectroscopy, and astrophysical applications

Biémont, Émile; Garnir, Henri-Pierre; Palmeri, P.; Li, Z. S.; Svanberg, Sune

doi:10.1046/j.1365-8711.2000.03094.x

Cited by 61 publications

(44 citation statements)

References 54 publications

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“…They find log ðPbÞ = +1.85 AE 0.05. More recent values of log gf (Biémont et al 2000) for those two lines are smaller by about 0.11 dex, and the solar abundance obtained is correspondingly higher, log ðPbÞ = +2.00 AE 0.06. The two effects essentially cancel out, and given that we use the old log gf and old solar lead abundance, the [Pb/Fe] abundance derived for the program star is not significantly affected.…”

Section: Pb Abundancementioning

confidence: 81%

Stellar Archaeology: A Keck Pilot Program on Extremely Metal-Poor Stars From the Hamburg/ESO Survey. III. The Lead (P[CLC]b[/CLC]) Star HE 0024−2523

Lucatello

Gratton

Cohen

et al. 2003

The Astronomical Journal

129

147

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We present a detailed abundance analysis, including spectral syntheses, of a very metal-poor ([Fe/H] ' À2.7) peculiar main-sequence star (HE 0024À2523) detected during the course of the Keck Pilot Program. Radial velocities of this star were obtained during four different observing runs over a time span of 1.1 yr and demonstrate that it is clearly a short-period spectroscopic binary. An orbital solution was obtained, and orbital parameters were determined with high precision. The rotational velocity was also measured (v rot sin i = 9.7 AE 1.5 km s À1 ); rotation appears likely to be synchronous with the orbit. The abundance analysis and spectral syntheses indicate that the object is a CH star characterized by extreme s-process enrichment, likely due to mass accretion from an evolved companion that has now probably become a white dwarf. The lead (Pb) abundance of (HE 0024À2523) is very high, the same as that of the recently discovered lead-rich, metal-poor star CS 29526-110, [Pb/Fe] = +3.3. The abundance ratio of the heavy to light s-elements, as characterized by Pb and Ba, [Pb/Ba] = +1.9, is the highest yet found for any metal-poor star and is about 0.7 dex higher than that of CS 29526-110. On the basis of the measured isotopic ratio of carbon (C 12 /C 13 $ 6) we argue that the mass donor must have had an original mass of at least $3 M . The unusually short period of this CH star suggests that it underwent a past common-envelope phase with its evolved companion. Our results are compared with the latest available models for asymptotic giant branch yields and s-process nucleosynthesis. We also discuss the possible connection between HE 0024À2523, the lithium depletion of halo stars, and halo blue straggler formation.

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Section: Pb Abundancementioning

confidence: 81%

Stellar Archaeology: A Keck Pilot Program on Extremely Metal-Poor Stars From the Hamburg/ESO Survey. III. The Lead (P[CLC]b[/CLC]) Star HE 0024−2523

Lucatello

Gratton

Cohen

et al. 2003

The Astronomical Journal

129

147

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“…We made an ultimately fruitless search for additional Pb i features, using the line list from Biémont et al (2000); all possible transitions were either too weak, too blended, or both.…”

Section: Abundance Analysis Technique and Line Listsmentioning

confidence: 99%

Chemical enrichment mechanisms inωCentauri: clues from neutron-capture elements

D’Orazi

Gratton

Pancino

et al. 2011

A&A

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Context. In the complex picture of multiple stellar populations in globular clusters (GCs), a special role is played by NGC 5139 (ω Centauri). At variance with the majority of GCs, ω Cen exhibits significant star-to-star variations in metallicity and in relative neutron-capture element abundance ratios with respect to Fe, along with split evolutionary sequences as revealed from colourmagnitude diagrams. Combining information from photometry and spectroscopy, several studies suggested that an age spread of several Gyr has to be invoked to explain (at least partially) some of the observed features. However, a comprehensive understanding of the formation, evolution and chemical enrichment processes is still not at hand. Aims. Relatively metal-rich ω Cen stars display neutron-capture abundance distributions dominated by contributions from the s-process, but it is not clear what roles have been played by the so-called main and weak s-process components in generating these abundances. To gain better insight into this question we derived lead (Pb) abundances for several ω Cen cluster members, because this element can only be produced by the main s-process. Methods. We analysed high-resolution UVES@VLT spectra of a sample of twelve red-giant branch stars, deriving abundances of Pb and also of Y, Zr, La, Ce, Eu, and the C+N+O sum. Spectral synthesis was applied to all features, taking into account isotopic shifts and/or hyperfine structure as needed. Results. We measured for the first time the Pb content in ω Cen, discovering a clear hint for a Pb production occurring at [Fe/H] > −1.7 dex. Our data suggest that the role of the weak component in the production of s-process elements is negligible. Moreover, evidence gathered from the abundances of other elements indicates that the main component occurring in this GC is peculiar and shifted towards higher mass polluters than the standard one.

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“…The usual notations log (A) = log(N A /N H ) + 12 and [A/B] = log(N A /N B ) * − log(N A /N B ) were adopted, where N A and N B are the numerical particle density of Smiljanic et al (2007). Barbuy et al (1999); (4) Allende Prieto et al (2001); (5) Lambert (1978); (6) Bielski (1975); (7) Biémont & Godefroid (1980); (8) Gratton & Sneden (1994); (9) Hannaford et al (1982); (10) Hannaford & Lowe (1983); (11) Biémont et al (1981); (12) Thévenin (1990); (13) Bergstrom et al (1988); (28) Corliss & Bozman (1962); (29) average between Kusz (1992) and Biémont & Lowe (1993); (30) Biémont et al (2000); "SUN" indicates log g f obtained through fits on the solar spectrum.…”

Section: Abundancesmentioning

confidence: 99%

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

Allen

Mello

2010

A&A

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Barium stars are optimal sites for studying the correlations between the neutron-capture elements and other species that may be depleted or enhanced, because they act as neutron seeds or poisons during the operation of the s-process. These data are necessary to help constrain the modeling of the neutron-capture paths and explain the s-process abundance curve of the solar system. Chemical abundances for a large number of barium stars with different degrees of s-process excesses, masses, metallicities, and evolutionary states are a crucial step towards this goal. We present abundances of Mn, Cu, Zn, and various light and heavy elements for a sample of barium and normal giant stars, and present correlations between abundances contributed to different degrees by the weak-s, mains, and r-processes of neutron capture, between Fe-peak elements and heavy elements. Data from the literature are also considered in order to better study the abundance pattern of peculiar stars. The stellar spectra were observed with FEROS/ESO. The stellar atmospheric parameters of the eight barium giant stars and six normal giants that we analyzed lie in the range 4300 < T eff /K < 5300, −0.7 < [Fe/H] ≤ 0.12 and 1.5 ≤ log g < 2.9. Carbon and nitrogen abundances were derived by spectral synthesis of the molecular bands of C 2 , CH, and CN. For all other elements we used the atomic lines to perform the spectral synthesis. A very large scatter was found mainly for the Mn abundances when data from the literature were considered. We found that [Zn/Fe] correlates well with the heavy element excesses, its abundance clearly increasing as the heavy element excesses increase, a trend not shown by the [Cu/Fe] and [Mn/Fe] ratios. Also, the ratios involving Mn, Cu, and Zn and heavy elements usually show an increasing trend toward higher metallicities. Our results suggest that a larger fraction of the Zn synthesis than of Cu is owed to massive stars, and that the contribution of the main-s process to the synthesis of both elements is small. We also conclude that Mn is mostly synthesized by SN Ia, and that a non-negligible fraction of the synthesis of Mn, Cu, and Zn is owed to the weak s-process.

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New f-values in neutral lead obtained by time-resolved laser spectroscopy, and astrophysical applications

Cited by 61 publications

References 54 publications

Stellar Archaeology: A Keck Pilot Program on Extremely Metal-Poor Stars From the Hamburg/ESO Survey. III. The Lead (P[CLC]b[/CLC]) Star HE 0024−2523

Stellar Archaeology: A Keck Pilot Program on Extremely Metal-Poor Stars From the Hamburg/ESO Survey. III. The Lead (P[CLC]b[/CLC]) Star HE 0024−2523

Chemical enrichment mechanisms inωCentauri: clues from neutron-capture elements

Mn, Cu, and Zn abundances in barium stars and their correlations with neutron capture elements

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