- ID:
- ivo://CDS.VizieR/I/116
- Title:
- Cape Photographic Catalog 1950.0 (CPC)
- Short Name:
- I/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog includes most of the stars from the 1900.0 Cordoba Zone Catalogues B and C in the zone -30 deg. -35 deg. at the equinox of 1925.0. Some of the fainter Cordoba stars have been omitted in the rather crowded regions in the Milky Way. The aim was to provide accurate places for an average of 9 to 10 stars per square degree as a reference for a rereduction of the AG positions. Most of the stars have visual magnitudes between 7 and 10. Positions and proper motions have been supplied from the General Catalogue for those stars that were too bright for accurate measurement on photographic plates. The positions are on the FK3 system for the equinox of 1950.0. The probable errors of the positions are nominally +/- 0.15" in both right ascension and declination. That of the proper motions should not exceed +/- 1.4"/century, or +/-14 in the units in which the proper motions expressed in arc are given in the catalog.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/I/85
- Title:
- Cape Photographic Catalogue 2
- Short Name:
- I/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the provisional positions for 51018 stars in the Cape zone -40 deg. to -52 deg., on the FK4 system for the equinox 1950.0. The internal mean error of a single coordinate obtained from the mean of r=four plates is estimated to be less than +/- 0.1" at the mean epoch of observation, about 1962. The systematic deviation from the FK4 system in a small area is probably also about +/-0.1". New proper motions have been determined for 22731 stars which are also in the Smithsonian Astrophysical Observatory (SAO) catalogue; the formal mean error of an annual proper motion in each coordinate is about +/-0.004"/a.
- ID:
- ivo://CDS.VizieR/I/108
- Title:
- Cape Photographic Durchmusterung
- Short Name:
- I/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The "Cape Photographic Durchmusterung" (CPD, Gill and Kapteyn 1895-1900) is a photographic survey of southern stars in the declination range -18 deg to -90 degrees. The original goal of the work was to carry out a southern survey similar to those of the "Bonner Durchmusterung" (BD, Argelander 1859-1862, see also Kuestner 1903) and Schoenfeld (1886) and the "Cordoba Durchmusterung" (CD, Thome 1892-1932) but using photographic plates which would provide a permanent record of the sky at the epoch of observation. The summary of the positional uncertainties quoted in the third volume of the published catalog gives +/- 0.28 sec (R.A.), +/- 0.044 arcmin (Dec.) for zones -18 to -57 degrees, +/- 0.157 sec + 0.0764/cos(delta) sec (R.A.), +/- 0.056 arcmin (Dec.) for zones -58 to -85 degrees, and +/- 0.157 sec + 0.0353/cos(delta) sec (R.A.), +/- 0.0127 arcmin (Dec.) for the polar plate where, as explained in the intro- duction to the third volume, many positions were derived from rectangular coordinates (these are positions reported to 0.1 sec (R.A.) and 0.001 arcmin (Dec.) in the -86 to -89 degree zones in the catalog). The probable error of a photographic magnitude, as determined by combining results for different magnitudes and weighting proportionately according to the numbers of stars in each class of magnitude, is given as +/- 0.055 mag. From an analysis of the faint magnitude limits on the plates discussed in the third volume introduction, the catalog as a whole can be considered complete to photographic magnitude 9.2, but it is stated that it will be found practically complete, in or near the Milky Way, to magnitude 9.5.
2664. Capodimonte Deep Field
- ID:
- ivo://CDS.VizieR/J/A+A/428/339
- Title:
- Capodimonte Deep Field
- Short Name:
- J/A+A/428/339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Capodimonte Deep Field (OACDF), a deep field covering an area of 0.5{deg}^2^ in the B, V, R optical bands plus six medium-band filters in the wavelength range 773-913nm. The field reaches the following limiting magnitudes: B_AB_~25.3, V_AB_~24.8 and R_AB_~25.1 and contains ~50000 extended sources in the magnitude range 18<=R_AB_<=25.0. Hence, it is intermediate between deep pencil beam surveys and very wide but shallow surveys.
- ID:
- ivo://CDS.VizieR/J/AJ/130/2804
- Title:
- Carbon abundances in metal-poor stars
- Short Name:
- J/AJ/130/2804
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We develop and test a method for the estimation of metallicities ([Fe/H]) and carbon abundance ratios ([C/Fe]) for carbon-enhanced metal-poor (CEMP) stars based on the application of artificial neural networks, regressions, and synthesis models to medium-resolution (1-2{AA}) spectra and J-K colors. We calibrate this method by comparison with metallicities and carbon abundance determinations for 118 stars with available high-resolution analyses reported in the recent literature.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A78
- Title:
- Carbon and nitrogen rate coefficients
- Short Name:
- J/A+A/625/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-energy inelastic collisions with neutral hydrogen atoms are important processes in stellar atmospheres, and a persistent source of uncertainty in non-LTE modelling of stellar spectra. We calculate and study excitation and charge transfer of CI and of NI due to such collisions. We use a previously presented method that is based on an asymptotic two-electron linear combination of atomic orbitals (LCAO) model of ionic-covalent interactions for the adiabatic potential energies, combined with the multichannel Landau- Zener model for the collision dynamics. We find that charge transfer processes typically lead to much larger rate coefficients than excitation processes, consistent with studies of other atomic species. Two-electron processes were considered and lead to non-zero rate coefficients that can potentially impact statistical equilibrium calculations. However, they were included in the model in an approximate way, via an estimate for the two-electron coupling that was presented earlier in the literature: the validity of these data should be checked in a future work.
- ID:
- ivo://CDS.VizieR/J/ApJ/735/41
- Title:
- Carbon and oxygen abundances in FGK stars
- Short Name:
- J/ApJ/735/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present carbon and oxygen abundances for 941 FGK stars -the largest such catalog to date. We find that planet-bearing systems are enriched in these elements. We self-consistently measure N_C_/N_O_, which is thought to play a key role in planet formation. We identify 46 stars with N_C_/N_O_>=1.00 as potential hosts of carbon-dominated exoplanets. We measure a downward trend in [O/Fe] versus [Fe/H] and find distinct trends in the thin and thick disks, supporting the work of Bensby et al. Finally, we measure sub-solar N_C_/N_O_=0.40^+0.11^_-0.07_, for WASP-12, a surprising result as this star is host to a transiting hot Jupiter whose dayside atmosphere was recently reported to have N_C_/N_O_>=1 by Madhusudhan et al. Our measurements are based on 15,000 high signal-to-noise spectra taken with the Keck 1 telescope as part of the California Planet Search. We derive abundances from the [OI] and CI absorption lines at {lambda}=6300 and 6587{AA} using the SME spectral synthesizer.
- ID:
- ivo://CDS.VizieR/J/A+A/621/A112
- Title:
- Carbon and oxygen in 107 dwarf stars
- Short Name:
- J/A+A/621/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results from the determination of stellar masses, carbon and oxygen abundances in the atmospheres of 107 stars from the CHEPS program. Our stars are drawn from a population with a significantly super-solar metallicity. At least 10 of these stars are known to host orbiting planets. In this work, we set out to understand the behavior of carbon and oxygen abundance in stars with different spectral classes, metallicities and Vsini, within the metal-rich stellar population. Masses of these stars were determined using the data from Gaia DR2 release. The oxygen and carbon abundances were determined by fitting the absorption lines. Oxygen abundances were determined by fits to the 6300.304{AA} OI line, and for the determination of the carbon abundances we used 3 lines of the CI atom and 12 lines of C_2_ molecule for the determination of carbon abundances. We determine masses and abundances of 107 CHEPS stars. There is no evidence that the [C/O] ratio depends on V sin i or the mass of the star, within our constrained range of masses, i.e. 0.82<M*/M_{sun}_<1.5 and metallicities -0.27<[Fe/H]<+0.39 and we confirm that metal-rich dwarf stars with planets are more carbon-rich in comparison with non-planet host stars, with a statistical significance of 96%. We find tentative evidence that there is a slight offset to lower abundance and a greater dispersion in oxygen abundances relative to carbon, and interpret this as potentially arising from the production of the oxygen being more effective at more metal-poor epochs. We also find evidence that for lower mass star's the angular momentum loss in star's with planets as measured by Vsini is steeper than star's without planets. In general, we find that the fast rotators (Vsini>5km/s) are massive stars.
- ID:
- ivo://CDS.VizieR/J/A+A/622/L4
- Title:
- Carbon and oxygen in metal-poor halo stars
- Short Name:
- J/A+A/622/L4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Carbon and oxygen are key tracers of the Galactic chemical evolution; in particular, a reported upturn in [C/O] towards decreasing [O/H] in metal-poor halo stars could be a signature of nucleosynthesis by massive Population III stars. We reanalyse carbon, oxygen, and iron abundances in 39 metal-poor turn-off stars. For the first time, we take into account 3D hydrodynamic effects together with departures from local thermodynamic equilibrium (LTE) when determining both the stellar parameters and the elemental abundances, by deriving effective temperatures from 3D non-LTE H{beta} profiles, surface gravities from Gaia parallaxes, iron abundances from 3D LTE FeII equivalent widths, and carbon and oxygen abundances from 3D non-LTE CI and OI equivalent widths. We find that [C/Fe] stays flat with [Fe/H], whereas [O/Fe] increases linearly up to 0.75dex with decreasing [Fe/H] down to -3.0dex. Therefore [C/O] monotonically decreases towards decreasing [C/H], in contrast to previous findings, mainly because the non-LTE effects for OI at low [Fe/H] are weaker with our improved calculations.
- ID:
- ivo://CDS.VizieR/J/A+A/655/A117
- Title:
- Carbon and oxygen in microlensed bulge dwarfs
- Short Name:
- J/A+A/655/A117
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Next to H and He, carbon is, together with oxygen, the most abundant element in the Universe and widely used when modelling the formation and evolution of galaxies and their stellar populations. For the Milky Way bulge, there are currently essentially no measurements of carbon in un-evolved stars, hampering our abilities to properly compare Galactic chemical evolution models to observational data for this still enigmatic stellar population. We aim to determine carbon abundances for our sample of 91 microlensed dwarf and subgiant stars in the Galactic bulge. Together with new determinations for oxygen this forms the first statistically significant sample of bulge stars that have C and O abundances measured, and for which the C abundances have not been altered by the nuclear burning processes internal to the stars. Our analysis is based on high-resolution spectra for a sample of 91 dwarf and subgiant stars that were obtained during microlensing events when the brightnesses of the stars were highly magnified. Carbon abundances were determined through spectral line synthesis of six CI lines around 9100{AA}, and oxygen abundances using the three OI lines at about 7770{AA}. One-dimensional (1D) MARCS model stellar atmospheres calculated under the assumption of local thermodynamic equilibrium (LTE) were used, and non-LTE corrections were applied when calculating the synthetic spectra for both C and O. Carbon abundances was possible to determine for 70 of the 91 stars in the sample and oxygen abundances for 88 of the 91 stars in the sample. The [C/Fe] ratio evolves essentially in lockstep with [Fe/H], centred around solar values at all [Fe/H]. The [O/Fe]-[Fe/H] trend has an appearance very similar to that observed for other alpha-elements in the bulge, with the exception of a continued decrease in [O/Fe] at super-solar [Fe/H], where other alpha-elements tend to level out. When dividing the bulge sample into two sub-groups, one younger than 8Gyr and one older than 8Gyr, the stars in the two groups follow exactly the elemental abundance trends defined by the solar neighbourhood thin and thick disks, respectively. Comparisons with recent models of Galactic chemical evolution in the [C/O]-[O/H] plane show that the models that best match the data are the ones that have been calculated with the Galactic thin and thick disks in mind. We conclude that carbon, oxygen, and the combination of the two support the idea that the majority of the stars in the Galactic bulge have a secular origin; that is, they are formed from disk material. We cannot exclude that a fraction of stars in the bulge could be classified as a classical bulge population, but it would have to be small. More dedicated and advanced models of the inner region of the Milky Way are needed to make more detailed comparisons to the observations.
