Astronomy and Astrophysics – Astronomy
Scientific paper
May 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993aas...182.6406c&link_type=abstract
American Astronomical Society, 182nd AAS Meeting, #64.06; Bulletin of the American Astronomical Society, Vol. 25, p.912
Astronomy and Astrophysics
Astronomy
Scientific paper
Observed properties of many short period millisecond pulsars (P < 10 ms) near the galactic disk support the standard spin-up scenario for their origins. Radio pulse properties of these ms pulsars (PSR 1937+21, PSR 1957+20, PSR 1855+09 and PSR 1953+29) are consistent with those expected from substantially spun-up neutron stars. The presence of low mass companions in extremely circular orbits in three out four cases indicates rather long mass transfer histories. However, the radio pulse profile of PSR 1257+12 is more similar to the pulse profiles of most canonical pulsars than these ms pulsars mentioned above. The existence of two companion planets around this pulsar is unique among the ms pulsars in the galactic disk. Here we suggest that this ms pulsar may have a different origin: core coalescence of a close binary system. We consider the evolution of a close binary consisting with two main sequence stars of masses 7 M_sun and 5 M_sun respectively. When the more massive one evolves into a giant, it is assumed that mass can be transfered to the companion through Roche-lobe overflow and the primary evolves into a compact core with mass about 1 M_sun. When the secondary (which now has mass 11M_sun) evolves into a giant, the mass transfer may bring the evolved primary into the envelope of the secondary, leading to the merger of the two cores. If the coalesced core collapses through a SN II, a neutron star with a rotation period of a few ms is expected. A neutron star formed by this scenario may also have a relatively weak magnetic field. Because the merged star inherits large angular momentum of the binary (J=M_1M_2sqrt {Ga/(M_1+M_2)}, where a ~ 10(12) cm is the initial separation of the binary), the typical angular momentum of the material in the envelope of the merged star is rather high ( ~ sqrt {Ga(M_1+M_2)}). The fallback material with mass of few percent solar mass may form a gas disk at radius 10(10-13) cm. The evolution of the gas disk may lead to the formation of planets. This work was performed under auspices of the US DOE.
No associations
LandOfFree
Is PSR 1257+12 a Spun-up Pulsar? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Is PSR 1257+12 a Spun-up Pulsar?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Is PSR 1257+12 a Spun-up Pulsar? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1850228