File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Magnetic field evolution of accreting neutron stars

TitleMagnetic field evolution of accreting neutron stars
Authors
KeywordsStars: binaries: close
Stars: magnetic fields
Stars:neutron
X-rays: stars
Issue Date1998
PublisherE D P Sciences. The Journal's web site is located at http://www.aanda.org
Citation
Astronomy And Astrophysics, 1998, v. 337 n. 2, p. 441-446 How to Cite?
AbstractWe study the evolution of the magnetic field of an accreting neutron star in the frozen field and incompressible fluid approximations. The plasma is accreted onto two polar caps and squeezes some of the surface material of the neutron star toward the equator. The frozen B-field is then pushed toward the equator and is eventually buried there. The magnetic field within the polar cap areas, which is defined by the Alfvèn radius, decreases due to the expansion of the polar cap areas resulting from the physical motion of the accreted material, which conserves the magnetic flux. But the decrease of the magnetic field also changes the Alfvèn radius which modifies the size of the polar cap and also affects the decrease of the magnetic flux within the polar caps. Therefore, the magnetic field enclosed by the polar caps appears to decay rapidly with a time scale of ∼ 10 5 mB/10 -3M ⊙/Ṁ/(10 18gs -1) years. As a consequence the magnetic field outside the polar cap is increasing because the total flux of the entire stellar surface is conserved in our approximations. The decrease of the polar cap magnetic field will stop and reach a minimum value ∼ 10 8G when the magnetic field outside the polar cap reaches B out ∼ 10 15G, which is strong enough to stop the motion of the accretion material across the stellar surface. However, this strong B out cannot be observed because the accreted matter stopped by this strong field cannot move toward the equator. Instead it moves inward and pulls this field inside the crust with a time scale ∼ 10 6H 5R 2 6ρ 14Ṁ -1 18 yr. Pulsars accreting similar masses but having very different magnetic field may result from different equations of state.
Persistent Identifierhttp://hdl.handle.net/10722/80495
ISSN
2014 Impact Factor: 4.378
2015 SCImago Journal Rankings: 2.446
References

 

DC FieldValueLanguage
dc.contributor.authorCheng, KSen_HK
dc.contributor.authorZhang, CMen_HK
dc.date.accessioned2010-09-06T08:07:05Z-
dc.date.available2010-09-06T08:07:05Z-
dc.date.issued1998en_HK
dc.identifier.citationAstronomy And Astrophysics, 1998, v. 337 n. 2, p. 441-446en_HK
dc.identifier.issn0004-6361en_HK
dc.identifier.urihttp://hdl.handle.net/10722/80495-
dc.description.abstractWe study the evolution of the magnetic field of an accreting neutron star in the frozen field and incompressible fluid approximations. The plasma is accreted onto two polar caps and squeezes some of the surface material of the neutron star toward the equator. The frozen B-field is then pushed toward the equator and is eventually buried there. The magnetic field within the polar cap areas, which is defined by the Alfvèn radius, decreases due to the expansion of the polar cap areas resulting from the physical motion of the accreted material, which conserves the magnetic flux. But the decrease of the magnetic field also changes the Alfvèn radius which modifies the size of the polar cap and also affects the decrease of the magnetic flux within the polar caps. Therefore, the magnetic field enclosed by the polar caps appears to decay rapidly with a time scale of ∼ 10 5 mB/10 -3M ⊙/Ṁ/(10 18gs -1) years. As a consequence the magnetic field outside the polar cap is increasing because the total flux of the entire stellar surface is conserved in our approximations. The decrease of the polar cap magnetic field will stop and reach a minimum value ∼ 10 8G when the magnetic field outside the polar cap reaches B out ∼ 10 15G, which is strong enough to stop the motion of the accretion material across the stellar surface. However, this strong B out cannot be observed because the accreted matter stopped by this strong field cannot move toward the equator. Instead it moves inward and pulls this field inside the crust with a time scale ∼ 10 6H 5R 2 6ρ 14Ṁ -1 18 yr. Pulsars accreting similar masses but having very different magnetic field may result from different equations of state.en_HK
dc.languageengen_HK
dc.publisherE D P Sciences. The Journal's web site is located at http://www.aanda.orgen_HK
dc.relation.ispartofAstronomy and Astrophysicsen_HK
dc.subjectStars: binaries: closeen_HK
dc.subjectStars: magnetic fieldsen_HK
dc.subjectStars:neutronen_HK
dc.subjectX-rays: starsen_HK
dc.titleMagnetic field evolution of accreting neutron starsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0004-6361&volume=337&spage=441&epage=446&date=1998&atitle=Magnetic+Field+Evolution+of+Accreting+Neutron+Starsen_HK
dc.identifier.emailCheng, KS: hrspksc@hkucc.hku.hken_HK
dc.identifier.authorityCheng, KS=rp00675en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.scopuseid_2-s2.0-0000863419en_HK
dc.identifier.hkuros38913en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0000863419&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume337en_HK
dc.identifier.issue2en_HK
dc.identifier.spage441en_HK
dc.identifier.epage446en_HK
dc.publisher.placeFranceen_HK
dc.identifier.scopusauthoridCheng, KS=9745798500en_HK
dc.identifier.scopusauthoridZhang, CM=7405492355en_HK

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats