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Author: search.filters.author.Ray, SubharthiSubject: search.filters.subject.Dense matter

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    Astrophysical consequences of diquark formation on the surface of strange star
    (2001-05-12) Dey, Mira; Sinha, Monika; Ray, Subharthi
    Compactness of some stars is explained if they are strange stars (SS) as shown by Dey et al.(1998) (D98) and Li et al. (1999a,b). In D98, a realistic potential was used in a Fock mean eld approximation within Dirac phe- nomenology, thereby simplifying the spinorial structure of the quarks. Using the plane wave states for the beta equi- librated u, d and s quark Fermi seas from D98 and the conventional spin dependent force between these quarks, we now nd energy lowering in some speci c spin-aligned states. This is a short range pairing between quarks of dif- ferent flavours and may lower the energy by several MeV for each diquark pair. The accretion driven X-ray and γ ray bursts in com- pact objects are believed to be due to thermonuclear or some other explosions which are short lived. These may in fact destroy the spin alignment of the quarks if these stars are SS. The subsequent alignment and production of copious diquark pairing may produce su cient energy to produce recurrent very long bursts seen in some such stars. The long time involved in these processes, we claim, is due to the weak interactions which are responsible for the equilibration of strange quark matter. In such a the case the elusive properties of some of the most massive objects in nature, the compact stars, can be accounted for by spin alignment of pairs of the smallest components of matter, - namely the quarks.
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    Possible evidence of surface vibration of realistic strange stars from stellar observations
    (2011-07-05) Ray, Subharthi; Dey, Jishnu; Dey, Mira; et al.
    Emission lines in the eV and keV range by certain stellar candidates from their recent analysis invoke the question of their possible origin. These stars under consideration, are the 4U 0614+091 (0.65, 0.86, and 1.31 keV ), 2S 0918−549 (0.8 keV with width 55 eV ), 4U 1543−624 (0.7 keV ), 4U 1850 −087 (0.7 keV ) and 4U 1820−30 (0.6 and 0.9 keV ) and also the 0.6 keV excess emission in RX J170930.2−263927. Recently, it has been suggested that the resonance absorption at ∼ in 0.7, 1.4, 2.1 and 2.8 keV 1E1207−5209 and 0.35, 0.7 and 1.4 keV RX J1856.5−3754 are due to harmonic surface vibrations in strange stars. We propose that these harmonic vibrations may also responsible for emission lines in the above mentioned compact stellar candidates.