- ID:
- ivo://CDS.VizieR/J/A+A/371/943
- Title:
- Lithium abundances for 185 main-sequence stars
- Short Name:
- J/A+A/371/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This table presents stellar atmospheric parameters, absolute magnitude, mass, age, equivalent width of the {lambda}6708 Li line, and non-LTE Li abundance. For the majority of stars the absolute magnitude has been derived from Hipparcos parallaxes but in a few cases (marked by :) a photometric value derived from the c_1_ index is given. Most stellar ages have errors of around 20% but those marked with `:' are more uncertain, and for stars close to the ZAMS no age is given.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/615/A151
- Title:
- Lithium abundances in 714 F and G dwarf stars
- Short Name:
- J/A+A/615/A151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a detailed analysis of Li in 714 nearby dwarf stars. Li abundances were determined through spectral line synthesis of the Li feature at 670.8 nm. The stellar sample traces the evolution of the Galactic thin and thick disks in the solar neighbourhood, and is the same as previously analysed by Bensby et al. (2014, Cat. J/A+A/562/A71) where stellar parameters and ages were taken from. The same sample was also used in Battistini & Bensby (2015, Cat. J/A+A/577/A9, 2016, Cat. J/A+A/586/A49) wherein abundances for odd iron-peak elements and r- and s-process elements can be found.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/46
- Title:
- Lithium abundances in HIP stars
- Short Name:
- J/ApJ/756/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive atmospheric parameters and lithium abundances for 671 stars and include our measurements in a literature compilation of 1381 dwarf and subgiant stars. First, a "lithium desert" in the effective temperature (T_eff_) versus lithium abundance (A_Li_) plane is observed such that no stars with T_eff_=~6075K and A_Li_=~1.8 are found. We speculate that most of the stars on the low A_Li_ side of the desert have experienced a short-lived period of severe surface lithium destruction as main-sequence or subgiant stars. Next, we search for differences in the lithium content of thin-disk and thick-disk stars, but we find that internal processes have erased from the stellar photospheres their possibly different histories of lithium enrichment. Nevertheless, we note that the maximum lithium abundance of thick-disk stars is nearly constant from [Fe/H]=-1.0 to -0.1, at a value that is similar to that measured in very metal-poor halo stars (A_Li_=~2.2). Finally, differences in the lithium abundance distribution of known planet-host stars relative to otherwise ordinary stars appear when restricting the samples to narrow ranges of T_eff_ or mass, but they are fully explained by age and metallicity biases. We confirm the lack of a connection between low lithium abundance and planets. However, we find that no low A_Li_ planet-hosts are found in the desert T_eff_ window. Provided that subtle sample biases are not responsible for this observation, this suggests that the presence of gas giant planets inhibit the mechanism responsible for the lithium desert.
- ID:
- ivo://CDS.VizieR/J/A+A/372/862
- Title:
- Lithium abundances in IC 2602 and IC 2391
- Short Name:
- J/A+A/372/862
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lithium abundances and [Fe/H] for a sample of late-type stars in the young open clusters IC 2602 and IC 2391. Abundances are based on high resolution spectra obtained at ESO (3.6m + CASPEC) and CTIO (4m + echelle spectrograph)
- ID:
- ivo://CDS.VizieR/J/A+A/634/A130
- Title:
- Lithium abundances in microlensed bulge dwarfs
- Short Name:
- J/A+A/634/A130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lithium abundances are presented for 91 dwarf and subgiant stars in the Galactic bulge. The analysis is based on line synthesis of the ^7^Li line at 6707{AA} in high-resolution spectra obtained during gravitational microlensing events, when the brightnesses of the targets were highly magnified. Our main finding is that bulge stars at sub-solar metallicities that are older than about eight billion years do not show any sign of Li production; that is, the Li trend with metallicity is flat or even slightly declining. This indicates that no lithium was produced during the first few billion years in the history of the bulge. This finding is essentially identical to what is seen for the (old) thick disk stars in the solar neighbourhood, and adds another piece of evidence for a tight connection between the metal-poor bulge and the Galactic thick disk. For the bulge stars younger than about eight billion years, the sample contains a group of stars at very high metallicities at [Fe/H]~=+0.4 that have lithium abundances in the range A(Li)=2.6-2.8. In the solar neighbourhood the lithium abundances have been found to peak at A(Li)~=3.3 at [Fe/H]~=+0.1 and then decrease by 0.4-0.5dex when reaching [Fe/H]~=+0.4. The few bulge stars that we have at these metallicities seem to support this declining A(Li) trend. This could indeed support the recent claim that the low A(Li) abundances at the highest metallicities seen in the solar neighbourhood could be due to stars from the inner disk, or the bulge region, that have migrated to the solar neighbourhood.
- ID:
- ivo://CDS.VizieR/J/ApJ/716/L166
- Title:
- Lithium abundances in red giants of M4
- Short Name:
- J/ApJ/716/L166
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The determination of Li and proton-capture element abundances in globular cluster (GC) giants allows us to constrain several key questions on the multiple population scenarios in GCs, from formation and early evolution to pollution and dilution mechanisms. In this Letter, we present our results on Li abundances for a large sample of giants in the intermediate-metallicity GC NGC 6121 (M4), for which Na and O have been already determined by Marino et al. (2008, Cat. J/A+A/490/625). The stars analyzed are both below and above the red giant branch bump luminosity. We found that the first and second generation stars share the same Li content, suggesting that a Li production must have occurred. This provides strong observational evidence supporting the scenario in which asymptotic giant branch stars are GC polluters.
- ID:
- ivo://CDS.VizieR/J/A+A/363/239
- Title:
- Lithium abundances in single giant stars
- Short Name:
- J/A+A/363/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the present work, we study the link between rotation and lithium abundance in giant stars of luminosity class III, on the basis of a large sample of 309 single stars of spectral type F, G and K. We have found a trend for a link between the discontinuity in rotation at the spectral type G0III and the behavior of lithium abundances around the same spectral type. The present work also shows that giant stars presenting the highest lithium contents, typically stars earlier than G0III, are those with the highest rotation rates, pointing for a dependence of lithium content on rotation, as observed for other luminosity classes. Giant stars later than G0III present, as a rule, the lowest rotation rates and lithium contents. A large spread of about five magnitudes in lithium abundance is observed for the slow rotators. Finally, single giant stars with masses 1.5<M/M_{sun}_<=2.5 w a clearest trend for a correlation between rotational velocity and lithium abundance.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/154
- Title:
- Lithium abundances in stars with planets
- Short Name:
- J/ApJ/724/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents a homogeneous determination of lithium abundances in a large sample of giant-planet-hosting stars (N=117) and a control sample of disk stars without detected planets (N=145). The lithium abundances were derived using a detailed profile fitting of the LiI doublet at 6708{AA} in LTE. The planet-hosting and comparison stars were chosen to have significant overlap in their respective physical properties, including effective temperatures, luminosities, masses, metallicities, and ages. The combination of uniform data and homogeneous analysis with well-selected samples makes this study well suited to probe for possible differences in the lithium abundances found in planet-hosting stars. An overall comparison between the two samples reveals no obvious differences between stars with and without planets. A closer examination of the behavior of the Li abundances over a narrow range of effective temperature (5700K<=T_eff_<=5850K) indicates subtle differences between the two stellar samples; this temperature range is particularly sensitive to various physical processes that can deplete lithium.
- ID:
- ivo://CDS.VizieR/J/ApJ/785/94
- Title:
- Lithium abundances of a large sample of red giants
- Short Name:
- J/ApJ/785/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The lithium abundances for 378 G/K giants are derived with non-local thermodynamic equilibrium correction considered. Among these are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective temperature, and rotational velocity, as well as the impact of a giant planet on G/K giants. The results show that the lithium abundance is a function of metallicity and effective temperature. The lithium abundance has no correlation with rotational velocity at v sin i<10 km/s. Giants with planets present lower lithium abundance and slow rotational velocity (v sin i<4 km/s). Our sample includes three Li-rich G/K giants, 36 Li-normal stars, and 339 Li-depleted stars. The fraction of Li-rich stars in this sample agrees with the general rate of less than 1% in the literature, and the stars that show normal amounts of Li are supposed to possess the same abundance at the current interstellar medium. For the Li-depleted giants, Li-deficiency may have already taken place at the main sequence stage for many intermediate mass (1.5-5 M_{sun}_)G/K giants. Finally, we present the lithium abundance and kinematic parameters for an enlarged sample of 565 giants using a compilation of the literature, and confirm that the lithium abundance is a function of metallicity and effective temperature. With the enlarged sample, we investigate the differences between the lithium abundance in thin-/thick-disk giants, which indicate that the lithium abundance in thick-disk giants is more depleted than that in thin-disk giants.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A36
- Title:
- Lithium abundances of bulge RGB stars
- Short Name:
- J/A+A/538/A36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A small number of K-type giants on the red giant branch (RGB) is known to be very rich in lithium (Li). This fact is not accounted for by standard stellar evolution theory. The exact phase and mechanism of Li enrichment is still a matter of debate. Our goal is to probe the abundance of Li along the RGB, from its base to the tip, to confine Li-rich phases that are supposed to occur on the RGB. For this end, we obtained medium-resolution spectra with the FLAMES spectrograph at the VLT in GIRAFFE mode for a large sample of 401 low-mass RGB stars located in the Galactic bulge. The Li abundance was measured in the stars with a detectable Li 670.8 nm line by means of spectral synthesis with COMARCS model atmospheres. A new 2MASS J-K-Teff calibration from COMARCS models is presented in the Appendix. Thirty-one stars with a detectable Li line were identified, three of which are Li-rich according to the usual criterion (log{epsilon}_Li_>1.5). The stars are distributed all along the RGB, not concentrated in any particular phase of the red giant evolution (e.g. the luminosity bump or the red clump). The three Li-rich stars are clearly brighter than the luminosity bump and red clump, and do not show any signs of enhanced mass loss. We conclude that the Li enrichment mechanism cannot be restricted to a clearly defined phase of the RGB evolution of low-mass stars (M~1M_{sun}_), contrary to earlier suggestions from disk field stars.