The chemical composition of the peculiar companion to the millisecond pulsar in NGC 6397

Abstract

We present the chemical composition of the bright companion to the millisecond pulsar J1740-5340 in NGC 6397, based on high resolution spectra. Though the large rotation velocity of the star broadens the lines and complicates the analysis, the derived abundances are found fully compatible with those of normal unperturbed stars in NGC 6397, with the exception of a few elements (Li, Ca, and C). The lack of C suggests that the star has been peeled down to regions where incomplete CNO burning occurs, favouring a scenario where the companion is a turn-off star which has lost most of its mass. In addition we found an unexpected large Li abundance, which suggests that fresh 7Li has been produced on the stellar surface.

arXiv comment9 pages, 5 figures, A&A, accepted

References in corpus (21)

• Evolutionary Binary Sequences for Low- and Intermediate-Mass X-ray Binaries
• The O-Na and Mg-Al Anticorrelations in Turn-Off and early Subgiants in Globular Clusters
• Predictions for self-pollution in globular cluster stars
• Distances and ages of NGC 6397, NGC 6752 and 47 Tuc
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• Metal Abundances of Red Clump Stars in Open Clusters: I. NGC 6819
• Chandra Exposes the Core Collapsed Globular Cluster NGC 6397
• The lithium content of the globular cluster NGC 6397
• Discovery of short-period binary millisecond pulsars in four globular clusters
• An eclipsing millisecond pulsar with a possible main-sequence companion in NGC 6397
• Chandra Study of a Complete Sample of Millisecond Pulsars in 47Tuc and NGC6397
• The bright optical companion to the eclipsing millisecond pulsar in NGC 6397
• Multiwavelength optical observations of chromospherically active binary systems. III. High resolution echelle spectra from Ca II H&K to Ca II IRT
• Multiwavelength optical observations of chromospherically active binary systems. I. Simultaneous H{alpha}, NaI D{1}, D{2}, and HeI D{3} observations
• Radial Velocity Studies of Close Binary Stars.VIII
• A Millisecond Pulsar Optical Counterpart with Large-Amplitude Variability in the Globular Cluster 47 Tucanae
• The eclipsing millisecond pulsar PSR J1740-5340 and its red straggler companion
• Accurate mass ratio and heating effects in the dual-line millisecond binary pulsar in NGC 6397
• Stellar Forensics II: Millisecond Pulsar Binaries
• The complex Halpha line profile of the bright companion to PSR J1740-5340 in NGC 6397
• Eclipsing binary millisecond pulsar PSR J1740-5340 -- evolutionary considerations and observational test

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• Radio Timing and Optical Photometry of the Black Widow System PSR J1953+1846A in the Globular Cluster M71
• Chandra-HETGS Characterization of an Outflowing Wind in the accreting millisecond pulsar IGR J17591-2342
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• 4FGL J1120.0-2204: A Unique Gamma-ray Bright Neutron Star Binary with an Extremely Low Mass Proto-White Dwarf
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• Lithium enhancement in X-ray binaries due to stellar rotation
• Neutron Stars and Black Holes in Star Clusters
• X-rays from the Eclipsing Millisecond Pulsar PSR J1740-5340 in the Globular Cluster NGC 6397
• Identification and characterization of optical companions to the population of millisecond pulsars in the globular cluster M3