Browsing by Author "Bombaci, Ignazio"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Rapidly rotating strange stars for a new equation of state of strange quark matter
    (2000-12-18) Bombaci, Ignazio; Thampan, A. V.; Datta, Bhaskar
    For a new equation of state of strange quark matter, we construct equilibrium sequences of rapidly rotating strange stars in general relativity. The sequences are the normal and supramassive evolutionary sequences of constant rest mass. We also calculate equilibrium sequences for a constant value of Ω corresponding to the most rapidly rotating pulsar PSR 1937 +21. In addition to this, we calculate the radius of the marginally stable orbit and its dependence on Ω, relevant for modeling of kilo–Hertz quasi–periodic oscillations in X–ray binaries.
  • No Thumbnail Available
    Item
    Temperature profiles of accretion discs around rapidly rotating strange stars in general relativity : a comparison with neutron stars
    (2001-07-05) Bhattacharyya, Sudip; Thampan, A. V.; Bombaci, Ignazio
    We compute the temperature pro les of accretion discs around rapidly rotating strange stars, using constant gravitational mass equilibrium sequences of these objects, considering the full e ect of general relativity. Beyond a certain critical value of stellar angular momentum (J), we observe the radius (rorb) of the innermost stable circular orbit (ISCO) to increase with J (a property seen neither in rotating black holes nor in rotating neutron stars). The reason for this is traced to the crucial dependence of drorb=dJ on the rate of change of the radial gradient of the Keplerian angular velocity at rorb with respect to J. The structure parameters and temperature pro les obtained are compared with those of neutron stars, as an attempt to provide signatures for distinguishing between the two. We show that when the full gamut of strange star equation of state models, with varying degrees of sti ness are considered, there exists a substantial overlap in properties of both neutron stars and strange stars. However, applying accretion disc model constraints to rule out sti strange star equation of state models, we notice that neutron stars and strange stars exclusively occupy certain parameter spaces. This result implies the possibility of distinguishing these objects from each other by sensitive observations through future X{ray detectors.