2009ApJ...692..723L

The discovery of the eccentric binary and millisecond pulsar J1903+03273 has raised interesting questions about the formation mechanisms of this peculiar system. Here we present a born-fast scenario for PSR J1903+03273. We assume that during the supernova (SN) explosion that produced the pulsar, a fallback disk was formed around and accreted onto the newborn neutron star. Mass accretion could accelerate the neutron star's spin to milliseconds, and decrease its magnetic field to ∼10⁸-10⁹ G, provided that there was sufficient mass (∼0.1 M_☉) in the fallback disk. The neutron star became a millisecond pulsar after mass accretion terminated. In the meanwhile the binary orbit has kept to be eccentric (due to the SN explosion) for ∼10⁹ yr. We have performed population synthesis calculations of the evolutions of neutron stars with a fallback disk, and found that there might be tens to hundreds of PSR J1903+03273 like systems in the Galaxy. This scenario also suggests that some fraction of isolated millisecond pulsars in the Galactic disk could be formed through the same channel.