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261. Abundances of heavy ions in ICMEs from 1998-2011
ID:
ivo://CDS.VizieR/J/ApJ/900/123
Title:
Abundances of heavy ions in ICMEs from 1998-2011
Short Name:
J/ApJ/900/123
Date:
20 Jan 2022 00:43:36
Publisher:
CDS
Description:
This statistical work studies the abundances and the charge states of the carbon, oxygen, and iron ions in 281 interplanetary coronal mass ejections (ICMEs) measured at 1 au by ACE spacecraft from 1998 to 2011. The Gaussian distribution test is applied, and the analysis of variance is used to quantify the similarity between two distributions of ionic charge states and abundances. The correlation coefficient is calculated to reveal the dependence of the abundances and the mean charge of heavy ions on the solar activity. The results show that the mean charge, the abundance, and the speed at 1 au are highly related to the sunspot number (SN). The O7+/O6+ shows statistical difference between the high speed and the low speed groups of ICMEs. Different from the cold materials inside ICMEs, the mean charge of carbon ions shows a positive relation to that of oxygen ions. The Mg/O in the studied ICMEs are much higher than that in the solar wind. Three types of charge distribution of C, O, and Fe ions are summarized. The fraction of each of the three types is related to the solar minimum or the solar maximum. The mean charge and the flux of oxygen ions show quasi-linear relations to the SN during solar minimum, and show fluctuations during maximum. The results reveal that the solar activity, which represents the solar magnetic field status by nature, controls the composition of heavy ions in ICMEs.
262. Abundances of HII regions in blue galaxies
ID:
ivo://CDS.VizieR/J/AZh/79/867
Title:
Abundances of HII regions in blue galaxies
Short Name:
J/AZh/79/867
Date:
21 Oct 2021
Publisher:
CDS
Description:
New expression for the ionization correction factors (ICF) are used to find the nebular-gas compositions in HII regions in blue compact dwarf galaxies (BCD). The abundances of He, N, O, Ne, S, and Ar in 41 HII regions are determined.
263. Abundances of HR 4487, 14 Hyd and 3 Cen A
ID:
ivo://CDS.VizieR/J/A+AS/129/563
Title:
Abundances of HR 4487, 14 Hyd and 3 Cen A
Short Name:
J/A+AS/129/563
Date:
21 Oct 2021
Publisher:
CDS
Description:
Ussing CASLEO echelle spectrograms, elemental abundances are derived for the sharp-lined non-magnetic CP stars HR 4487, 14 Hya and 3 Cen A. The first two stars are members of the Mercury-Manganese subgroup and have abundances which are similar to other such peculiar stars. The third is a hotter related star. The detection of Mn II lines in its spectrum adds to this relationship.
264. Abundances of 19 K-type giants in moving groups
ID:
ivo://CDS.VizieR/J/MNRAS/422/2969
Title:
Abundances of 19 K-type giants in moving groups
Short Name:
J/MNRAS/422/2969
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the stellar parameters of 19 K-type giants and their abundances for 13 chemical elements (Al, Ba, Ca, Fe, K, Mg, Mn, Na, Ni, Sc, Si, Ti and V), selected from two moving groups, covering the metallicity range of -0.6<[Fe/H]<0.2, based on high-resolution spectra. Most of the elemental abundances show similar trends as in previous studies, except for Al, Na and Ba, which are seriously affected by evolution. The abundance ratios of [Na/Mg] increase smoothly with higher [Mg/H], and those of [Al/Mg] decrease slightly with increasing [Mg/H]. The abundance ratios of [Mg/Ba] show a distinction between these two moving groups, which is mainly induced by chemical evolution and also partly by kinematic effects. The inhomogeneous metallicity of each star from the moving groups demonstrates that these stars had different chemical origins before they were kinematically aggregated. This favours a dynamical resonant theory.
265. Abundances of LAMOST giants from APOGEE DR12
ID:
ivo://CDS.VizieR/J/ApJ/836/5
Title:
Abundances of LAMOST giants from APOGEE DR12
Short Name:
J/ApJ/836/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this era of large-scale spectroscopic stellar surveys, measurements of stellar attributes ("labels," i.e., parameters and abundances) must be made precise and consistent across surveys. Here, we demonstrate that this can be achieved by a data-driven approach to spectral modeling. With The Cannon, we transfer information from the APOGEE survey to determine precise T_eff_, logg, [Fe/H], and [{alpha}/M] from the spectra of 450000 LAMOST giants. The Cannon fits a predictive model for LAMOST spectra using 9952 stars observed in common between the two surveys, taking five labels from APOGEE DR12 as ground truth T_eff_, logg, [Fe/H], [{alpha}/M], and K-band extinction A_k_. The model is then used to infer T_eff_, logg, [Fe/H], and [{alpha}/M] for 454180 giants, 20% of the LAMOST DR2 stellar sample. These are the first [{alpha}/M] values for the full set of LAMOST giants, and the largest catalog of [{alpha}/M] for giant stars to date. Furthermore, these labels are by construction on the APOGEE label scale; for spectra with S/N>50, cross-validation of the model yields typical uncertainties of 70K in T_eff_, 0.1 in logg, 0.1 in [Fe/H], and 0.04 in [{alpha}/M], values comparable to the broadly stated, conservative APOGEE DR12 uncertainties. Thus, by using "label transfer" to tie low-resolution (LAMOST R~1800) spectra to the label scale of a much higher-resolution (APOGEE R~22500) survey, we substantially reduce the inconsistencies between labels measured by the individual survey pipelines. This demonstrates that label transfer with The Cannon can successfully bring different surveys onto the same physical scale.
266. Abundances of late G/K dwarfs in solar neighborhood
ID:
ivo://CDS.VizieR/III/27A
Title:
Abundances of late G/K dwarfs in solar neighborhood
Short Name:
III/27A
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this investigation, a technique developed by Spinrad and Taylor for obtaining metal abundances of late-type stars, and used by them in an earlier investigation of evolved stars (see Cat. II/47), is applied to field dwarfs in the solar vicinity and to the Hyades. The colors determined from photoelectric spectrum-scanner observations are listed in the "raw_data.dat" file; the derived blocking factors are given in the "blocking.dat" file. These results were published as the Table 5 of the paper.
267. Abundances of late K and M dwarfs in binary systems
ID:
ivo://CDS.VizieR/J/AJ/145/52
Title:
Abundances of late K and M dwarfs in binary systems
Short Name:
J/AJ/145/52
Date:
21 Oct 2021
Publisher:
CDS
Description:
Knowledge of late K and M dwarf metallicities can be used to guide planet searches and constrain planet formation models. However, the determination of metallicities of late-type stars is difficult because visible wavelength spectra of their cool atmospheres contain many overlapping absorption lines, preventing the measurement of equivalent widths. We present new methods, and improved calibrations of existing methods, to determine metallicities of late K and M dwarfs from moderate resolution (1300<R<2000) visible and infrared spectra. We select a sample of 112 wide binary systems that contain a late-type companion to a solar-type primary star. Our sample includes 62 primary stars with previously published metallicities, as well as 50 stars with metallicities determined from our own observations. We use our sample to empirically determine which features in the spectrum of the companion are best correlated with the metallicity of the primary. We find ~120 features in K and M dwarf spectra that are useful for predicting metallicity. We derive metallicity calibrations for different wavelength ranges, and show that it is possible to get metallicities reliable to <0.10dex using either visible, J-, H-, or K-band spectra. We find that the most accurate metallicities derived from visible spectra requires the use of different calibrations for early-type (K5.5-M2) and late-type (M2-M6) dwarfs. Our calibrations are applicable to dwarfs with metallicities of -1.04<[Fe/H]<+0.56 and spectral types from K7 to M5. Lastly, we use our sample of wide binaries to test and refine existing calibrations to determine M dwarf metallicities. We find that the {zeta} parameter, which measures the ratio of TiO can CaH bands, is correlated with [Fe/H] for super-solar metallicities, and {zeta} does not always correctly identify metal-poor M dwarfs. We also find that existing calibrations in the K and H bands are quite reliable for stars with [Fe/H]>-0.5, but are less useful for more metal-poor stars.
268. Abundances of late-type stars
ID:
ivo://CDS.VizieR/J/ApJ/797/69
Title:
Abundances of late-type stars
Short Name:
J/ApJ/797/69
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of several absorption lines of neutral phosphorus (P, Z=15) in archival near-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We derive phosphorus abundances or interesting upper limits in 14 late-type stars with metallicities spanning -3.8<[Fe/H]<-0.1. Previously, phosphorus had only been studied in Galactic stars with -1.0<[Fe/H]<+0.3. Iron lines reveal abundance offsets between the optical and ultraviolet regions, and we discuss and apply a correction factor to account for this offset. In stars with [Fe/H]>-1.0, the [P/Fe] ratio decreases toward the solar value with increasing metallicity, in agreement with previous observational studies. In stars with [Fe/H]<-1.0, $<[P/Fe]$>=+0.04+/-0.10, which overlaps with the [P/Fe] ratios found in several high-redshift damped Lyman-{alpha} systems. This behavior hints at a primary origin in massive stars.
269. Abundances of LMC bar and disk stars
ID:
ivo://CDS.VizieR/J/A+A/560/A44
Title:
Abundances of LMC bar and disk stars
Short Name:
J/A+A/560/A44
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper compares the chemical evolution of the Large Magellanic Cloud (LMC) to that of the Milky Way (MW) and investigates the relation between the bar and the inner disc of the LMC in the context of the formation of the bar. We obtained high-resolution and mid signal-to-noise ratio spectra with FLAMES/GIRAFFE at ESO/VLT (Proposals 072.B-0293(B) and 078.B-0323(A), P.I. Vanessa Hill) and performed a detailed chemical analysis of 106 and 58 LMC field red giant stars (mostly older than 1Gyr), located in the bar and the disc of the LMC respectively. To validate our stellar parameter determinations and abundance measurement procedures, we performed thorough tests using the well-known mildly metal-poor Milky-Way thick disc giant Arcturus (HD 124897, alpha Boo). We measured elemental abundances for O, Mg, Si, Ca, Ti (alpha-elements), Na (light odd element), Sc, V, Cr, Co, Ni, Cu (iron-peak elements), Y, Zr, Ba, La and Eu (s- and r-elements). We used the automated tool DAOSPEC to measure the equivalent width (EW) and their associated error, and we used the grid of OSMARCS model atmospheres together with the spectrum synthesis code turbospectrum to convert the EW into abundances. Since our stars are giants, atmosphere models and radiative transfer were both in spherical geometry. We built the atmosphere model for a given set of stellar parameters by interpolation onto the OSMARCS grid with the interpolation routine written by T. Masseron.
270. Abundances of LX Per
ID:
ivo://CDS.VizieR/J/AJ/145/167
Title:
Abundances of LX Per
Short Name:
J/AJ/145/167
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present spectroscopic observations of LX Per carried out using the Korean Bohyunsan Observatory Echelle Spectrograph (BOES) with spectral resolving power R=80000. The spectrograph was attached to the 1.8m telescope. The fit of synthetic spectra to the observed spectrum of the system allowed us to find the component parameters and the abundances of chemical elements in the atmospheres of the components. The strong CaII H&K emissions are confirmed; we also found emission lines in the CaII reversals' triplet absorptions at the wavelengths of 8498, 8542, and 8662{AA} in the spectrum of the cooler component of LX Per. A unique photometric solution using the distorted light curves of three different epochs was made. The spot model light curves were fitted to the 1981, 1982, and 1983 observations successfully by adjusting only spot parameters. We could infer that the variation of spot location and size was the main reason for the changing shape of light curves. The main feature of the abundance patterns of both components was the apparent deficiency of heavy (Z>30) elements. Only elements with strong lines, namely Y and Ba, were detected. Correlations of relative abundances of chemical elements with condensation temperatures and second ionization potentials of these elements, which can be explained by the accretion of dust and gas, were found.

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