- ID:
- ivo://CDS.VizieR/J/ApJ/873/L5
- Title:
- Magnetic field measurements of Ap/Bp stars
- Short Name:
- J/ApJ/873/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on magnetic field measurements of 157 chemically peculiar A/B stars (Ap/Bp) based on resolved, magnetically split absorption lines present in H-band spectra provided by the Sloan Digital Sky Survey (SDSS)/Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. These stars represent the extreme magnetic end of a still-growing sample of >900 Ap/Bp stars selected among the APOGEE telluric standard stars as those with CeIII absorption lines and/or literature Ap/Bp classifications. The lines most frequently resolved into their split components for these stars in the H-band pertain primarily pertain to CeIII, CrII, FeI, MnII, SiI, and CaII, in addition to one or more unidentified ions. Using mean magnetic field modulus (<B>) estimates for transitions with known Lande factors, we estimate effective Lande factors for 5 CeIII lines and 15 unknown lines and proceed to measure <B> of 157 stars, only 3 of which have previous literature estimates of <B>. This 183% increase in the number of Ap/Bp stars for which <B> has been measured is a result of the large number of stars observed by SDSS/APOGEE, extension of high-resolution Ap/Bp star observations to fainter magnitudes, and the advantages of long wavelengths for resolving magnetically split lines. With <B>~25kG, the star 2MASS J02563098+4534239 is currently the most magnetic star of the SDSS/APOGEE sample. Effective Lande factors, representative line profiles, and magnetic field moduli are presented. The validity of the results is supported using optical, high-resolution, follow-up spectra for 29 of the stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/475/1053
- Title:
- Magnetic fields in Ap/Bp stars
- Short Name:
- J/A+A/475/1053
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated a sample of 28 well-known spectroscopically-identified magnetic Ap/Bp stars, with weak, poorly-determined or previously undetected magnetic fields. The aim of this study is to explore the weak part of the magnetic field distribution of Ap/Bp stars. Using the MuSiCoS and NARVAL spectropolarimeters at Telescope Bernard Lyot (Observatoire du Pic du Midi, France) and the cross-correlation technique Least Squares Deconvolution (LSD), we have obtained 282 LSD Stokes $V$ signatures of our 28 sample stars, in order to detect the magnetic field and to infer its longitudinal component with high precision (median sigma=40G).
- ID:
- ivo://CDS.VizieR/J/MNRAS/372/1804
- Title:
- Magnetic fields of chem. peculiar stars
- Short Name:
- J/MNRAS/372/1804
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectropolarimetric observations of 96 chemically peculiar (CP) main-sequence stars have been carried out at the 6-m telescope at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) with the aim of searching for the presence of stellar magnetic fields. The stars selected for investigation were CP stars known to have strong anomalies in the wavelength region of the continuum flux depression around {lambda} 5200{AA}. This selection was conducted with the aid of low-resolution spectral observations, made with the SAO RAS 1-m telescope, and of published differential photometric data. Magnetic fields have been successfully detected in 72 stars of which only three stars were previously known to have magnetic fields. For two stars, the longitudinal component of the magnetic field B_e_exceeds 5kG: HD178892 - 7.4kG, and HD258686 - 6.7kG. We failed to reliably detect the magnetic field in the other 24 CP stars. These stars are mostly fast rotators, a feature which hampers accurate measurements of B_e_. It is demonstrated in this paper that selecting candidate magnetic stars by considering their photometric indices Z or {Delta}alpha}, or alternatively, by inspecting low-resolution spectra around the {lambda}5200{AA} flux depression, considerably increases the detection rate.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/73.178
- Title:
- Magnetic fields of CP stars (2011)
- Short Name:
- J/other/AstBu/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of measuring longitudinal magnetic fields (B_e_), rotation velocities (v_e_sini), 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.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/75.294
- Title:
- Magnetic fields of CP stars (2012)
- Short Name:
- J/other/AstBu/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of measuring longitudinal magnetic fields (Be), rotation velocities (v_esini), and radial velocities (VR) of 163 stars observed with the Main Stellar Spectrograph (MSS) of the 6-m BTA telescope of the Special Astrophysical Observatory in 2012. Observations of standard stars without magnetic fields confirm the absence of systematic errors capable of introducing distortions into the longitudinal-field measurement results.
- ID:
- ivo://CDS.VizieR/J/PAZh/31/437
- Title:
- Magnetic peculiar stars elemental abundances
- Short Name:
- J/PAZh/31/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Temperature dependance of the abundances of the chemical elements Si, Ca, Cr and Fe in the atmospheres of normal, metallic-line (Am), magnetic peculiar (Ap) and pulsating magnetic peculiar (r0Ap) stars in the range 6000-15000K.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/74.66
- Title:
- Main sequence magnetic stars properties
- Short Name:
- J/other/AstBu/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reconsidered the previous studies of properties of magnetic stars based on the latest data on average surface magnetic fields of 177 stars. New, corrected results have been obtained that allow a better understanding of the phenomenon of magnetic chemically peculiar stars.
- ID:
- ivo://CDS.VizieR/J/A+A/640/A40
- Title:
- 1002 mCP stars from LAMOST DR4
- Short Name:
- J/A+A/640/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present work is aimed at identifying new mCP stars using spectra collected by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). Suitable candidates were selected by searching LAMOST DR4 spectra for the presence of the characteristic 5200{AA} flux depression. Spectral classification was carried out with a modified version of the MKCLASS code and the accuracy of the classifications was estimated by comparison with results from manual classification and the literature. Using parallax data and photometry from Gaia DR2, we investigated the space distribution of our sample stars and their properties in the colour-magnitude diagram. Our final sample consists of 1002 mCP stars, most of which are new discoveries (only 59 common entries with the Catalogue of Ap, HgMn and Am stars). Traditional mCP star peculiarities have been identified in all but 36 stars, highlighting the efficiency of the code's peculiarity identification capabilities. The derived temperature and peculiarity types are in agreement with manually derived classifications and the literature. Our sample stars are between 100Myr and 1Gyr old, with the majority having masses between 2M_{sun}_ and 3M_{sun}_. Our results could be considered as strong evidence for an inhomogeneous age distribution among low-mass (M<3M_{sun}_) mCP stars; however, we caution that our sample has not been selected on the basis of an unbiased, direct detection of a magnetic field. We identified several astrophysically interesting objects: the mCP stars LAMOST J122746.05+113635.3 and LAMOST J150331.87+093125.4 have distances and kinematical properties in agreement with halo stars; LAMOST J034306.74+495240.7 is an eclipsing binary system (Porb=5.1435+/-0.0012d) hosting an mCP star component; and LAMOST J050146.85+383500.8 was found to be an SB2 system likely comprising of an mCP star and a supergiant component. With our work, we significantly increase the sample size of known Galactic mCP stars, paving the way for future in-depth statistical studies.
- ID:
- ivo://CDS.VizieR/J/other/RAA/15.1182
- Title:
- M Dwarf catalog of LAMOST DR1
- Short Name:
- J/other/RAA/15.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic catalog of 93 619 M dwarfs from the first data release of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) general survey. During sample selection, M giant contamination was eliminated using 2MASS photometry and CaH/TiO molecular indices. For each spectrum, the spectral subtype and values are provided including radial velocity, H{alpha} equivalent width, a series of prominent molecular band indices, and the metal-sensitive parameter {zeta}, as well as distances and the space motions for high S/N objects. In addition, H{alpha} emission lines are measured to examine the magnetic activity properties of M dwarfs and 7179 active ones are found. In particular, a subsample with significant variation in magnetic activity is revealed through observations from different epochs. Finally, statistical analysis for this sample is performed, including the metallicity classification, the distribution of molecular band indices and their errors.
- ID:
- ivo://CDS.VizieR/J/A+A/455/303
- Title:
- Nainital-Cape Survey. II. Null results
- Short Name:
- J/A+A/455/303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search for photometric variability in chemically peculiar A type stars in the northern hemisphere. High-speed photometric observations of Ap and Am star candidates have been carried out from ARIES (Manora Peak, Nainital) using a three-channel fast photometer attached to the ARIES 104-cm Sampurnanand telescope.
