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- 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/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/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.
- ID:
- ivo://CDS.VizieR/J/A+A/418/1073
- Title:
- Emission lines in optical spectrum of 3 Cen A
- Short Name:
- J/A+A/418/1073
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Weak emission lines in the optical spectrum of the helium-weak chemically peculiar star 3 Cen A are tabulated. The observed wavelengths, line identification information and equivalent widths are presented based on data obtained with the ESO 1.5m telescope and FEROS instrument (16-17 May 2000) and the VLT with UVES spectrograph (24 June 2001). Table 2 is a listing of all recorded emission lines arranged by wavelength and including unidentified features. Table 3 arranges the identified lines according to their ion and multiplet.
- ID:
- ivo://CDS.VizieR/J/MNRAS/396/2061
- Title:
- Equivalent widths of EP UMA (HR 4330)
- Short Name:
- J/MNRAS/396/2061
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemically peculiar star HR 4330 (=HD 96707, EP UMa) was observed using the 2-m Himalayan Chandra Telescope at the Indian Astronomical Observatory, Hanle, India, for studying the variations in its spectral features. It was found that the spectral features of CaII 3933{AA} and SrII 4077{AA} were showing rapid variations in their equivalent widths with a periodicity of 0.28+/-0.02d. Such short-term variations suggest that there could be a dynamically active surface with rapid variation in the conditions of the stellar atmosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A106
- Title:
- eta Car velocity-resolved imaging
- Short Name:
- J/A+A/594/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass loss from massive stars is not understood well. eta Carinae is a unique object for studying the massive stellar wind during the luminous blue variable phase. It is also an eccentric binary with a period of 5.54yr. The nature of both stars is uncertain, although we know from X-ray studies that there is a wind-wind collision whose properties change with orbital phase. We want to investigate the structure and kinematics of eta Car's primary star wind and wind-wind collision zone with a high spatial resolution of ~6mas (~14au) and high spectral resolution of R=12000. Observations of eta Car were carried out with the ESO Very Large Telescope Interferometer (VLTI) and the AMBER instrument between approximately five and seven months before the August 2014 periastron passage. Velocity-resolved aperture-synthesis images were reconstructed from the spectrally dispersed interferograms. Interferometric studies can provide information on the binary orbit, the primary wind, and the wind collision.
- ID:
- ivo://CDS.VizieR/J/A+A/450/763
- Title:
- Evolutionary state of magnetic CP stars
- Short Name:
- J/A+A/450/763
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The photospheres of about 5-10% of the upper main sequence stars exhibit remarkable chemical anomalies. Many of these chemically peculiar (CP) stars have a global magnetic field, the origin of which is still a matter of debate. We present a comprehensive statistical investigation of the evolution of magnetic CP stars, aimed at providing constraints to the theories that deal with the origin of the magnetic field in these stars.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A199
- Title:
- Fit parameters & ephemerides of 650 mCP stars
- Short Name:
- J/A+A/622/A199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic, chemically peculiar stars are known for exhibiting surface abundance inhomogeneities (chemical spots) that lead to photometric and spectroscopic variability with the rotation period. It is commonly assumed that the surface structures are causally connected with the global magnetic field that dominates the photospheric and subphotospheric layers of these stars. As a rule, the observed magnetic fields show a simple dipole-like geometry, with the magnetic axis being noncollinear to the rotational one. The present study aims at detecting underlying patterns in the distribution of photometric spots in a sample of 650 magnetic, chemically peculiar stars and examines their link to the magnetic field topology. Photometric time-series observations from the ASAS-3 archive were employed to inspect the light-curve morphology of our sample stars and divide them into representative classes described using a principal component analysis. Theoretical light curves were derived from numerous simulations assuming different spot parameters and following the symmetry of a simple dipole magnetic field. These were subsequently compared with the observed light curves. The results from our simulations are in contradiction with the observations and predict a much higher percentage of double-wave light curves than is actually observed. We thereby conclude that the distribution of the chemical spots does not follow the magnetic field topology, which indicates that the role of the magnetic field in the creation and maintenance of the surface structures may be more subsidiary than what is predicted by theoretical studies.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/74.62
- Title:
- Fundamental parameters of CP stars
- Short Name:
- J/other/AstBu/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents the results of determination of fundamental parameters (effective temperature, surface gravity, luminosity, mass, radius, rotation velocity, and radial velocity) for 146 stars observed at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences with the Main Stellar Spectrograph during 2009-2011; 124 of the stars are magnetic or potentially magnetic objects. We obtained and analyzed at least 500 pairs of circularly-polarized-emission spectra. Various methods and approaches were used in estimating the fundamental parameters.
