Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/356/1256
- Title:
- Elemental abundance analysis of HR 8216
- Short Name:
- J/MNRAS/356/1256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed the abundance analysis of the cool magnetic CP star HR 8216 (=HD 204411) using 2.4{AA}/mm Dominion Astrophysical Observatory Reticon exposures covering ll 3830-4770{AA} with a typical signal-to-noise ratio of 200. The spectrograms were measured interactively with the graphics computer program REDUCE. We performed a fine analysis with an ATLAS9 metal-rich model atmosphere whose predictions best matched the optical region fluxes and the Hg profile. HR 8216's anomalies are primarily an enhancement of many iron peak elements with the rare earths elements much less enhanced than for many similar cool magnetic CP stars .Using the results of the fine analysis we synthetized the spectrum. Comparison with the observed spectrum showed that agreement is better.
- ID:
- ivo://CDS.VizieR/J/A+A/371/1078
- Title:
- Elemental abundance of 4 normal B and A stars
- Short Name:
- J/A+A/371/1078
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Elemental abundances analysis of the superficially normal B and A stars {alpha} Dra (A0 III), {tau} Her (B5 IV), {gamma} Lyr (B9 III), and HR 7926 (B8 II-III) are performed consistent with previous studies of this series using spectrograms obtained with Reticon and CCD detectors. Comparisons of the first two analysis with those of the same stars performed earlier in this series which used mostly coadded photographic plates show the general consistency of the derived elemental abundances. A slight increase in the adopted effective temperature produces a corresponding increase in the derived abundances. In these stars the He/H ratios are found to be close to solar. Except for {gamma} Lyr the metals show for the most part marginally subsolar abundance values. But this star has Al, Ca, Sc, and Sr abundances that are substantially underabundant as well as other underabundant values.
- ID:
- ivo://CDS.VizieR/J/MNRAS/364/272
- Title:
- Elemental abundances in Blanco 1
- Short Name:
- J/MNRAS/364/272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution spectroscopy is used to determine the detailed chemical abundances of a group of eight F- and G-type stars in the young open cluster Blanco 1. An average [Fe/H] of +0.04+/-0.02 (internal error)+/-0.04 (external error) is found, considerably lower than a previous spectroscopic estimate for this cluster. The difference is due mainly to our adoption of significantly cooler temperatures that are consistent with both photometric and spectroscopic constraints. Blanco 1 exhibits subsolar [Ni/Fe](0.18+/-0.01+/-0.01), [Si/Fe](0.09+/-0.02+/-0.03), [Mg/Fe](0.14+/-0.02+/-0.03) and [Ca/Fe](0.09+/-0.03+/-0.03); ratios that are not observed among nearby field stars.
- ID:
- ivo://CDS.VizieR/J/A+A/420/673
- Title:
- Elemental abundances of CP2 star HR 5049
- Short Name:
- J/A+A/420/673
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spectrum synthesis analysis for photospheric lines in the magnetic B star HR 5049 is presented, based on a high quality spectrogram obtained with the EMMI spectrograph attached to the NTT at ESO. It is found that light elements such as He, C and O are under-abundant. One of the most notable features is the deficiency of He by more than -2.0dex. Co and Cl are over-abundant by +3.5dex and +1.9dex, respectively. Other iron peak elements are over-abundant ranging from +0.47dex (Ti II) to +1.94 dex (Cr I). For rare earth elements, the lines of once-ionized species are generally weak, while the third spectra (especially those of Pr and Nd) are very prominent. Although rare earth elements show significant over-abundances ranging from +3.0dex to as large as +4.0dex, Ba has the solar abundance. The Nd-Pr abundance difference, which shows an apparent decreasing trend with increasing effective temperature among CP stars, is found to be unusually small in HR 5049.
- ID:
- ivo://CDS.VizieR/J/A+A/364/237
- Title:
- Elemental abundances of Deneb
- Short Name:
- J/A+A/364/237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study presents a detailed model atmosphere abundance analysis of Deneb which was performed using Kurucz LTE ATLAS9 model atmospheres. The atmospheric parameters were determined from Mg I/II and Fe I/II equilibrium, and by fitting the H{gamma} profile and optical region spectrophotometry. The compromise values which best satisfy these criteria are T_eff_ = 9000 K and log g = 1.45. The Mg I, Mg II, Si II, Ti II, Cr II, Fe I, and Fe II lines yield microturbulences of 3.60, 6.50, 8.50, 8.00, 11.90, 3.60, and 10.40 km/s, respectively. An average microturbulence of 7 km/s was used for the other atomic species.
- ID:
- ivo://CDS.VizieR/J/A+A/406/975
- Title:
- Elemental abundances of four A-B stars
- Short Name:
- J/A+A/406/975
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The superficially normal stars {theta} And (A2 V), {epsilon} Del (B6 III), {epsilon} Aqr (A1.5 V), and {iota} And (B9 V), which have rotationally broadened line profiles, are analyzed in a manner consistent with previous studies of this series using 2.4{AA}/mm spectrograms obtained with CCD detectors and S=N>=200. Their variable radial velocities strongly suggest they are spectroscopic binaries. As no evidence is seen for lines of their companions they are analyzed as single stars. Their derived abundances are generally near solar. But those for {theta} And suggest that it is possibly a fast rotating Am star.
- ID:
- ivo://CDS.VizieR/J/BaltA/14/51
- Title:
- Elemental abundances of 4 Lac and nu Cep
- Short Name:
- J/BaltA/14/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Elemental abundance analysis based on high S/N and high resolution Dominion Astrophysical Observatory spectrograms have been performed for two early type supergiants: 4 Lac (B9 Iab) and {nu} Cep (A2 Ia). Lines as weak as of order 5m{AA} are employed in this study. The projected rotational velocities of these stars are 14 and 26km/s, respectively. Both stars show similar radial velocity amplitudes, macroturbulent velocities and the same general elemental abundance trends. Their He, CNO and light element abundances are solar or overabundant while the iron peak and heavy element abundances are solar or underabundant. Detailed LTE model atmosphere abundance analysis shows that 4 Lac has nuclearly processed matter in its photosphere while {nu} Cep does not.
- ID:
- ivo://CDS.VizieR/J/AJ/127/373
- Title:
- Elemental abundances of 3 red giants in Ter 7
- Short Name:
- J/AJ/127/373
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemical abundances in three giants in Terzan 7, a globular cluster associated with the Sagittarius dwarf galaxy, have been determined using high-resolution spectra obtained with the UVES spectrograph on the ESO 8.2m Kueyen telescope. We find the overall metallicity of the stars to be [Fe/H]=-0.61+/-0.07, which is slightly higher than that previously evaluated from photometry and used for the age determination of this cluster. This metallicity yields an age of about 6Gyr, which is slightly lower than derived from previous estimates. The relative abundance ratios of various chemical elements to iron lie between those of its host galaxy's metal-poor and metal-rich stars and reveal an intriguing similarity to the pattern seen in the Large Magellanic Cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/406/987
- Title:
- Elemental abundances of three CP stars
- Short Name:
- J/A+A/406/987
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We used data from the EBASIM spectrograph of the 2.1-m CASLEO telescope to study three rather sharp-lined late B to early A stars {xi} Oct (B6 IV), {alpha} Sex (B9.5 III), and 68 Tau (A2 IV). These measurements are compared with those from the Anglo-Austrialian Telescope for the first star and to those from the coude spectrograph of the 1.22-m telescope of the Dominion Astrophysical Observatory (DAO) for the other two stars. The equivalent width scales of the EBASIM and the DAO data are similar. Thus for the latter two stars the DAO data is also used in the analyses. Both {xi} Oct and {alpha} Sex generally have abundances close to those of the Sun in the range of values found for other normal stars with similar effective temperatures. The abundance pattern for 68 Tau is that of a metallic-lined star as is well known.
