English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

PSR J1903+0327 is a mili-second pulsar with a mass of 1.67 M_{\odot} in ahighly eccentric orbit (e=0.44) around a main-sequence star. This unique systemcannot be reconciled with current observations where milli-second pulsars aregenerally seen to orbit white dwarfs in almost exactly circular orbits. Currenttheoretical models of binary and stellar formation and evolution cannot explainthe high eccentricity of this system either. In this work, we present three newepochs of optical spectroscopy for the companion to PSR J1903+0327, obtained toconfirm the association of the main-sequence star with the pulsar. These 3 newepochs together with the 2 previous ones obtained by Freire et al. (2011)firmly establish the high eccentricity of the companion's orbit as predicted bypulsar timing. Using all five epochs of optical data, we have provided anindependent estimate of the mass-ratio, R=1.56\pm0.15 as well as the systemicradial velocity of the binary, \gamma= 42.1\pm2.5 km/s. We constrain thespectral type of the pulsar companion to lie between F5 V -- G0 V (a slightlyearlier type than suggested previously) by measuring the equivalent widths oftwo of the three Ca-triplet lines (8498 \AA, 8542 \AA) and the Paschen line at8598 \AA (P14); we also broadly constrain the metallicity of the companion.Additionally, we have placed a somewhat better limit on the rotational velocityof the pulsar companion of v_{rot}\sin{i} \leq 66 km/s which is still notsufficient to allow a test of general relativity using this system.

PSR J1903+0327 : A Unique Milli-Second Pulsar with a Main-Sequence Companion Star