
TY  - JOUR
A1  - Melatos, A. 
A1  - Phinney, E. S. 
T1  - Hydromagnetic Structure of a Neutron Star Accreting at Its Polar Caps
JF  - Publications of the Astronomical Society of Australia
JO  - Publ. Astron. Soc.  Aust.
Y1  - 2002
VL  - 18
IS  - 4
SP  - 421
EP  - 430
KW  - accretion, accretion disks &#8212; pulsars: general &#8212; stars: magnetic fields &#8212; stars: neutron
UR  - https://doi.org/10.1071/AS01056 
N2  - The hydromagnetic structure of a neutron star accreting symmetrically at both magnetic poles is calculated as a function of accreted mass, Ma, starting from a polytropic sphere plus central magnetic dipole (Ma =0) and evolving the configuration through a quasistatic sequence of twodimensional, Grad&#8211;Shafranov equilibria as Ma increases. It is found that the accreted material spreads equatorward under its own weight, compressing the magnetic field into a thin boundary layer and burying it everywhere except in a narrow, equatorial belt. The magnetic dipole moment of the star is given by =5.2&#215;1024(B0/1012.5G)1.3( Ma/10-8M yr-1)0.18(Ma/M)-1.3Gcm3, and the fractional difference between its principal moments of inertia is given by =2.110-5 (B0/1012.5G)0.27 (Ma/10-8M yr-1)0.18(Ma/M)1.7, for Ma in the range 10-5 Ma/M 10-1,where B0 is the pre-accretion magnetic field strength, and Ma is the accretion rate. 
ER  -

