A plethora of new, magnetic chemically peculiar stars from LAMOST DR4

Abstract

Magnetic chemically peculiar (mCP) stars are important to astrophysics because their complex atmospheres lend themselves perfectly to the investigation of the interplay between such diverse phenomena as atomic diffusion, magnetic fields, and stellar rotation. 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 5200A 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 previously known). 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 100 Myr and 1 Gyr 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. We identified several astrophysically interesting objects: two mCP stars have distances and kinematical properties in agreement with halo stars; an eclipsing binary system hosting an mCP star component; and an SB2 system likely comprising of an mCP star and a supergiant component.

arXiv comment62 pages, 24 figures, 10 tables, corrected some typos and minor mistakes; corrected wrong number of stars with absolute parallax errors less than 25%, redundant figure removed

References in corpus (48)

• Gaia Data Release 2. Summary of the contents and survey properties
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main Sequence Stars
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• Global survey of star clusters in the Milky Way II. The catalogue of basic parameters
• A Gaia DR2 view of the Open Cluster population in the Milky Way
• Gaia Data Release 2: Catalogue validation
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• A fossil origin for the magnetic fields of A-stars and white dwarfs
• Galactic Reddening in 3D from Stellar Photometry - An Improved Map
• The first WASP public data release
• Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
• On the metallicity of open clusters. III. Homogenised sample
• Astrophysical supplements to the ASCC-2.5. Ia. Radial velocities of about 55000 stars and mean radial velocities of 516 Galactic open clusters and associations
• Evolutionary state of magnetic chemically peculiar stars
• A new catalogue of Stroemgren-Crawford uvbybeta photometry
• Searching for links between magnetic fields and stellar evolution. II. The evolution of magnetic fields as revealed by observations of Ap stars in open clusters and associations
• Searching for links between magnetic fields and stellar evolution. I. A survey of magnetic fields in open cluster A- and B-type stars with FORS1
• Searching for links between magnetic fields and stellar evolution III. Measurement of magnetic fields in open cluster Ap stars with ESPaDOnS
• Chemically peculiar stars and their temperature calibration
• An Investigation of the Rotational Properties of Magnetic Chemically Peculiar Stars
• New catalogue of Chemically Peculiar stars, and Statistical Analysis
• MOBSTER - II. Identification of rotationally variable A stars observed with \emph{TESS} in Sectors 1 to 4
• On the detection of chemically peculiar stars using Delta a photometry
• The nature of the light variability of the silicon star HR 7224
• Pulsation versus metallicism in Am stars as revealed by LAMOST and WASP
• Evolution of Magnetic Fields in Stars Across the Upper Main Sequence: II. Observed distribution of the magnetic field geometry
• The applications of the MHD Alfven wave oscillation model for kHz quasi-periodic oscillations
• Theoretical analysis of the atmospheres of CP stars. Effects of the individual abundance patterns
• Gaia's view of the $\lambda$ Boo star puzzle
• The Kepler view of magnetic chemically peculiar stars
• Doppler imaging of chemical spots on magnetic Ap/Bp stars. Numerical tests and assessment of systematic errors
• A comprehensive comparison between APOGEE and LAMOST: Radial Velocities and Atmospheric Stellar Parameters
• The 5200A flux depression of chemically peculiar stars: I. Synthetic Delta a photometry - the normality line
• Stellar model atmospheres with magnetic line blanketing
• Stellar model atmospheres with magnetic line blanketing. II. Introduction of polarized radiative transfer
• HD66051: the first eclipsing binary hosting an early-type magnetic star
• A Large Sample of Am Candidates from LAMOST Data Release 1
• Metallic-Line Stars Identified from Low Resolution Spectra of LAMOST DR5
• Exploring the spectral \textit{information content} in the LAMOST medium-resolution survey (MRS)
• New solar metallicity measurements
• The structural evolution of galaxies with both thin and thick discs
• Ultraviolet and visual flux and line variations of one of the least variable Bp stars HD 64740
• HD 99458: First time ever Ap-type star as a $\delta$ Scuti pulsator in a short period eclipsing binary?
• On the evolutionary status of chemically peculiar stars of the upper main sequence
• Surface abundance and the hunt for stratification in chemically peculiar hot subdwarfs: PG 0909+276 and UVO 0512-08
• HD66051, an eclipsing binary hosting a highly peculiar, HgMn-related star

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• V680 Mon -- a young mercury-manganese star in an eclipsing heartbeat system
• Rotational Velocities of Am and Non-CP Stars based on Kepler and LAMOST DR5
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• Exploring the Stellar Rotation of Early-type Stars in the LAMOST Medium-resolution Survey. III. Evolution
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• High-velocity CP2 stars in the Galactic halo
• Magnetism in LAMOST CP stars observed by TESS
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