MOST detects g- and p-modes in the B supergiant HD 163899 (B2 Ib/II )

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dc.creator Saio, H.
dc.creator Kuschnig, R.
dc.creator Gautschy, A.
dc.creator Cameron, Chris
dc.creator Walker, G. A. H.
dc.creator Matthews, J. M.
dc.creator Guenther, David B.
dc.creator Moffat, A. F .J.
dc.creator Rucinski, S. M.
dc.creator Sasselov, D.
dc.date.accessioned 2013-10-30T19:04:38Z
dc.date.available 2013-10-30T19:04:38Z
dc.date.issued 2006-10-20
dc.identifier.issn 0004-637X
dc.identifier.uri http://library2.smu.ca/xmlui/handle/01/25307
dc.description Publisher's version/PDF
dc.description.abstract The Microvariability and Oscillations of Stars (MOST ) satellite observed the B supergiant HD 163899 (B2 Ib/ II ) for 37 days as a guide star and detected 48 frequencies [less than tilde] 2.8 cycles day [superscript minus 1] with amplitudes of a few millimagnitudes (mmag) and less. The frequency range embraces g- and p-mode pulsations. It was generally thought that no g-modes are excited in less luminous B supergiants because strong radiative damping is expected in the core. Our theoretical models, however, show that such g-modes are excited in massive post-main-sequence stars, in accordance with these observations. The nonradial pulsations excited in models between 20 M[circle dot] at log T[subscript eff][approximately equal] 4.41 and 15 M[circle dot] at log T[subscript eff] [approximately equal] 4.36 are roughly consistent with the observed frequency range. Excitation by the Fe bump in opacity is possible because g-modes can be partially reflected at a convective zone associated with the hydrogen-burning shell, which significantly reduces radiative damping in the core. The MOST light curve of HD 163899 shows that such a reflection of g-modes actually occurs and reveals the existence of a previously unrecognized type of variable, slowly pulsating B supergiants (SPBsg) distinct from [alpha] Cyg variables. Such g-modes have great potential for asteroseismology. en_CA
dc.language.iso en en_CA
dc.publisher American Astronomical Society
dc.relation.uri http://dx.doi.org/10.1086/507409
dc.rights Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
dc.subject.lcsh Early stars
dc.subject.lcsh Stellar oscillations
dc.subject.lcsh Supergiant stars
dc.title MOST detects g- and p-modes in the B supergiant HD 163899 (B2 Ib/II ) en_CA
dc.type Text en_CA
dcterms.bibliographicCitation Astrophysical Journal 650(2), 1111-1118. (2006)


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Article is made available in accordance with the publisher’s policy and is subject to copyright law. Please refer to the publisher’s site. Any re-use of this article is to be in accordance with the publisher’s copyright policy. This posting is in no way granting any permission for re-use to the reader/user.
 
Published Version: http://dx.doi.org/10.1086/507409
 
 

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