We present a catalogue of 2572 new double stars with common proper motion and angular separation smaller than 2 arcminutes, found in PM2000 proper motion catalogue. To this catalogue we add an annex of 259 of common proper motion doublestars with angular separation between 2 and 5 arcminutes and proper motion larger than 50mas/yr. A by-product of this work was the identification in PM2000 and remeasurement of 926 WDS double stars.
We studied the polarization behavior of the quasar 3C 273 over the 1mm wavelength band at ALMA with a total bandwidth of 7.5GHz across 223-243GHz at 0.8" resolution, corresponding to 2.1kpc at the distance of 3C 273. With these observations we were able to probe the optically thin polarized emission close to the jet base, and constrain the magnetic field structure. We computed the Faraday rotation measure using simple linear fitting and Faraday rotation measure synthesis. In addition, we modeled the broadband behavior of the fractional Stokes Q and U parameters (qu-fitting). The systematic uncertainties in the polarization observations at ALMA were assessed through Monte Carlo simulations. We find the unresolved core of 3C 273 to be 1.8% linearly polarized. We detect a very high rotation measure (RM) of (5.0+/-0.3)x10^5^rad/m^2^ over the 1 mm band when assuming a single polarized component and an external RM screen. This results in a rotation of >40{deg} of the intrinsic electric vector position angle, which is significantly higher than typically assumed for millimeter wavelengths. The polarization fraction increases as a function of wavelength, which according to our qu-fitting could be due to multiple polarized components of different Faraday depth within our beam or to internal Faraday rotation. With our limited wavelength coverage we cannot distinguish between the cases, and additional multifrequency and high angular resolution observations are needed to determine the location and structure of the magnetic field of the Faraday active region. Comparing our RM estimate with values obtained at lower frequencies, the RM increases as a function of observing frequency, following a power law with an index of 2.0+/-0.2, consistent with a sheath surrounding a conically expanding jet. We also detect ~0.2% circular polarization, although further observations are needed to confirm this result.
Fine analyses of the silicon star HD 43819 and the CP star HD 147550 are presented using ATLAS9 model atmospheres whose predictions fit the optical region spectrophotometry and H{gamma} profiles and have the same bulk metallicity as the deduced abundances. For HD 43819 except for scandium and nickel, the derived abundances of the iron peak elements are around 10 times solar while those of the rare earths are about 1000 times solar. The lighter elements are generally underabundant except for silicon and calcium which are overabundant. HD 147550 is helium and calcium poor; carbon, magnesium, aluminum, scandium, titanium, and iron normal; and sulfur, chromium, manganese, nickel, strontium, zirconium, barium, europium, and mercury rich. It is a nonmagnetic CP star intermediate between the HgMn and the hot Am stars.
To enlarge our data base of chemically peculiar stars, we compiled published data concerning the He-weak and He-rich stars observed by high-resolution spectroscopy techniques during last decades. Twenty He-weak and 28 He-rich stars have been added to the data base. We have also distinguished roAp stars from stars previously identified as Ap stars. To deepen our knowledge on statistical overview of the abundance anomalies versus the physical parameters of stars, we compared our data with previous compilations. We applied statistical tests on our data and found interesting correlations for effective temperature and surface gravity for all type of stars and a few correlations for projected rotation velocity only for He-rich stars. Because of the lack of the data, we could not check whether being a member of binary system is affecting on chemical peculiarities of those stars.
With the aim to corroborate the result of a search for chemically peculiar stars in the Large Magellanic Cloud (LMC), we present measurements obtained from CCD imaging of two fields, one containing a young open cluster (NGC 1711). ************************************************************************** * * * Sorry, but the author(s) never supplied the tabular material * * announced in the paper * * * **************************************************************************
We present the results of measuring longitudinal magnetic fields (B_e), rotation velocities (v_e_sini), and radial velocities (V_r_) of 44 stars observed with the Main Stellar Spectrograph (MSS) of the 6-m BTA telescope of the Special Astrophysical Observatory in 2009. Observations of standard stars without magnetic fields confirm the absence of systematic errors capable of introducing distortions into the longitudinal-field measurement results. In this work we comment on the results for each of the stars.
This catalog presents the results of magnetic field measurements for 39 chemically peculiar and 3 normal main sequence stars used as standard stars. Observations were carried out with the Main Stellar Spectrograph of the Russian 6-m telescope during 2007. The accuracy analysis for the longitudinal magnetic field measurements of the stars confirms that the systematic errors do not exceed 10-20G and are within the quoted limits. The absence of significant instrumental deviations follows from the measurements of theBD CP stars with well-known B_e_ variation curves.
We present the results of measuring longitudinal magnetic fields (B_e_), rotation velocities (v_esini_), and radial velocities (V_r_) of 92 stars observed with the Main Stellar Spectrograph (MSS) of the 6-m BTA telescope of the Special Astrophysical Observatory in 2010. Observations of standard stars without magnetic fields confirm the absence of systematic errors capable of introducing distortions into the longitudinal-field measurement results.
We present the results of the magnetic field measurements of 37 chemically peculiar and 4 normal main sequence stars using circularly polarized spectra obtained in 2008 with a Zeeman analyzer on the Main Stellar Spectrograph (MSS) of the Russian 6-m telescope (BTA). Four new magnetic stars have been discovered (HD25999, HD35100, HD96237, and HD279021), the presence of a field was suspected in two stars (HD2887 and BD-12 2366), 16 previously known CP stars were continued to be monitored to study their fields. The results of the longitudinal magnetic field B_e_ measurements show that in stars with narrow spectral lines, systematic errors in B_e_ determination do not exceed 10-20G, which is within the statistical error. Our study of stars with reliable phase curves of the longitudinal field B_e_ show that there are no instrumental effects which can distort the observations.