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1431. Li-rich giants atomic lines
ID:
ivo://CDS.VizieR/J/A+A/364/674
Title:
Li-rich giants atomic lines
Short Name:
J/A+A/364/674
Date:
21 Oct 2021
Publisher:
CDS
Description:
A detailed analysis has been carried out for a sample of 16 red giants showing a strong Li I 670.8nm line. Ten of them were detected in a survey by Castilho et al. (1998A&AS..127..139C), and the other 6 stars are Li-rich giants selected from the literature. Element abundances in the sample Li-rich giants are similar to those in normal red giants, differing only by their high Li abundance and infrared excess. This suggests that Li-rich giants may correspond to a phase of stellar evolution of normal red giants, when Li is produced and transported to the atmosphere.
1432. L379IRS3 radio lines
ID:
ivo://CDS.VizieR/J/AZh/93/409
Title:
L379IRS3 radio lines
Short Name:
J/AZh/93/409
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of spectral observations of the region of massive star formation L379IRS3 (IRAS 18265-1517) are presented. The observations were carried out with the 30-m Pico Veleta radio telescope (Spain) at seven frequencies in the 1-mm, 2-mm, and 3-mm wavelength bands. Lines of 24 molecules were detected, from simple diatomic or triatomic species to complex eight- or nine-atom compounds such as CH_3_OCHO or CH_3_OCH_3_. Rotation diagrams constructed from methanol and methyl cyanide lines were used to determine the temperature of the quiescent gas in this region, which is about 40-50K. In addition to this warm gas, there is a hot component that is revealed through high-energy lines of methanol and methyl cyanide, molecular lines arising in hot regions, and the presence of H_2_O masers and Class II methanol masers at 6.7GHz, which are also related to hot gas. One of the hot regions is probably a compact hot core, which is located near the southern submillimeter peak and is related to a group of methanol masers at 6.7GHz. High-excitation lines at other positions may be associated with other hot cores or hot post-shock gas in the lobes of bipolar outflows. The rotation diagrams can be use to determine the column densities and abundances of methanol (10^-9^) and methyl cyanide (about 10^-11^) in the quiescent gas. The column densities of A- and E-methanol in L379IRS3 are essentially the same. The column densities of other observed molecules were calculated assuming that the ratios of the molecular level abundances correspond to a temperature of 40 K. The molecular composition of the quiescent gas is close to that in another region of massive star formation, DR21(OH). The only appreciable difference is that the column density of SO2 in L379IRS3 is at least a factor of 20 lower than the value in DR21(OH). The SO_2_/CS and SO2/OCS abundance ratios, which can be used as chemical clocks, are lower in L379IRS3 than in DR21(OH), suggesting that L379IRS3 is probably younger than DR21(OH).
1433. Lithium abundances in AMBRE stars
ID:
ivo://CDS.VizieR/J/A+A/595/A18
Title:
Lithium abundances in AMBRE stars
Short Name:
J/A+A/595/A18
Date:
21 Oct 2021
Publisher:
CDS
Description:
The goal of this paper is to investigate the lithium stellar content of Milky Way stars in order to put constraints on the lithium chemical enrichment in our Galaxy, in particular in both the thin and thick discs. We show that the interstellar lithium abundance increases with metallicity by 1dex from [M/H]=-1dex to +0.0dex. Moreover, we find that this lithium ISM abundance decreases by about 0.5dex at super-solar metallicity. Based on a chemical separation, we also observed that the stellar lithium content in the thick disc increases rather slightly with metallicity while the thin disc shows a steeper increase. The lithium abundance distribution of alpha-rich metal-rich stars has a peak at A(Li)~3 dex. We conclude that the thick disc stars suffered of a low lithium chemical enrichment, showing lithium abundances rather close to the Spite plateau while the thin disc stars clearly show an increasing lithium chemical enrichment with the metallicity, probably thanks to the contribution of low-mass stars.
1434. Lithium abundances in stars with planets
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.
1435. Lithium abundances of a large sample of red giants
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.
1436. Lithium in Praesepe
ID:
ivo://CDS.VizieR/J/AJ/106/1080
Title:
Lithium in Praesepe
Short Name:
J/AJ/106/1080
Date:
21 Oct 2021
Publisher:
CDS
Description:
Echelle observations are presented of lithium in 63 F and G dwarfs of the Praesepe cluster. For stars earlier than about G0V, Praesepe follows the same trends seen in the Hyades, which has approximately the same age and composition. Stars in Praesepe later than about G5V have more Li than their Hyades counterparts, possibly because Praesepe is slightly younger than the Hyades or has slightly lower metallicity. Significant differences in the abundance of Li are seen among stars of the same color, and, as in the Hyades, there is a tendency for the deviant stars to be binaries to the extent that duplicity in Praesepe is known. There are also stars with much less Li than most cluster members yet which appear to be true members of Praesepe. The close binary KW 181 has a normal Li abundance, despite the fact that similar close binaries in the Hyades are Li rich.
1437. LkH{alpha} 101 and the young cluster in NGC 1579
ID:
ivo://CDS.VizieR/J/AJ/128/1233
Title:
LkH{alpha} 101 and the young cluster in NGC 1579
Short Name:
J/AJ/128/1233
Date:
21 Oct 2021
Publisher:
CDS
Description:
The central region of the dark cloud L1482 is illuminated by LkH{alpha} 101, a heavily reddened (A_V_~10mag) high-luminosity (>=8x10^3^L_Sun_) star having an unusual emission-line spectrum plus a featureless continuum. About 35 much fainter (mostly between R=16 and >21) H{alpha} emitters have been found in the cloud. Their color-magnitude distribution suggests a median age of about 0.5Myr, with considerable dispersion. There are also at least five bright B-type stars in the cloud, presumably of about the same age; none show the peculiarities expected of HAeBe stars. Dereddened, their apparent V magnitudes lead to a distance of about 700pc. Radio observations suggest that the optical object LkH{alpha} 101 is in fact a hot star surrounded by a small H II region, both inside an optically thick dust shell.
1438. LMC F supergiants
ID:
ivo://CDS.VizieR/J/A+A/293/347
Title:
LMC F supergiants
Short Name:
J/A+A/293/347
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
1439. LMC PNe [OIII] 5007{AA} and H{beta} flux
ID:
ivo://CDS.VizieR/J/MNRAS/405/1349
Title:
LMC PNe [OIII] 5007{AA} and H{beta} flux
Short Name:
J/MNRAS/405/1349
Date:
21 Oct 2021
Publisher:
CDS
Description:
Our previous identification and spectroscopic confirmation of 431 faint, new planetary nebulae (PNe) in the central 25deg^2^ region of the Large Magellanic Cloud (LMC) permit us to now examine the shape of the LMC planetary nebula luminosity function (PNLF) through an unprecedented 10mag range. The majority of our newly discovered and previously known PNe were observed using the 2dF, multi-object fibre spectroscopy system on the 3.9-m Anglo-Australian Telescope and the FLAMES multi-object spectrograph on the 8-m Very Large Telescope. We present reliable [OIII] 5007{AA} and H{beta} flux estimates based on calibrations to well-established PN fluxes from previous surveys and spectroscopic standard stars.
1440. 4 LMC SFRs velocity profile maps
ID:
ivo://CDS.VizieR/J/A+A/621/A62
Title:
4 LMC SFRs velocity profile maps
Short Name:
J/A+A/621/A62
Date:
21 Oct 2021
Publisher:
CDS
Description:
The aim of our study is to investigate the physical properties of the star-forming interstellar medium (ISM) in the Large Magellanic Cloud (LMC) by separating the origin of the emission lines spatially and spectrally. The LMC provides a unique local template to bridge studies in the Galaxy and high redshift galaxies because of its low metallicity and proximity, enabling us to study the detailed physics of the ISM in spatially resolved individual star-forming regions. Following Okada et al. (2015A&A...580A..54O), we investigate different phases of the ISM traced by carbon-bearing species in four star-forming regions in the LMC, and model the physical properties using the KOSMA-{tau} PDR model. We mapped 3-13 arcmin^2^ areas in 30 Dor, N158, N160, and N159 along the molecular ridge of the LMC in [C II] 158 {mu}m with GREAT on board SOFIA. We also observed the same area with CO(2-1) to (6-5), ^13^CO(2-1) and (3-2), [C I] ^3^P_1_-^3^P_0_ and ^3^P_2_-^3^P_1_ with APEX. For selected positions in N159 and 30 Dor, we observed [O I] 145 {mu}m and [O I] 63 {mu}m with upGREAT. All spectra are velocity resolved. In all four star-forming regions, the line profiles of CO, ^13^CO, and [C I] emission are similar, being reproduced by a combination of Gaussian profiles defined by CO(3-2), whereas [C II] typically shows wider line profiles or an additional velocity component. At several positions in N159 and 30 Dor, we observed the velocity-resolved [O I] 145 and 63 {mu}m lines for the first time. At some positions, the [O I] line profiles match those of CO, at other positions they are more similar to the [C II] profiles. We interpret the different line profiles of CO, [C II] and [O I] as contributions from spatially separated clouds and/or clouds in different physical phases, which give different line ratios depending on their physical properties. We modeled the emission from the CO, [C I], [C II], and [O I] lines and the far-infrared continuum emission using the latest KOSMA-{tau} PDR model, which treats the dust-related physics consistently and computes the dust continuum SED together with the line emission of the chemical species. We find that the line and continuum emissions are not well-reproduced by a single clump ensemble. Toward the CO peak at N159 W, we propose a scenario that the CO, [C II], and [O I] 63 {mu}m emission are weaker than expected because of mutual shielding among clumps.

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