HEAD Division Meeting 1999, April 1999
Session 15. X-Ray Binaries
Poster, Tuesday, April 13, 1999, 8:30am-6:02pm, Gold Room

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[15.05] The Coriolis Effect in KQPOs in Neutron Star Binaries and the Determination of Neutron Star Radius

Lev Titarchuk (NASA/GSFC and GMU), Vladimir Osherovich (NASA/GSFC)

The rotation of neutron star magnetosphere (NSM) affects (through the Coriolis force) the oscillations of the blobs which presumably are formed in disk within a few neutron star radii. We put forth that effect leads to the appearance of the high hybrid frequency which is a combination of the Keplerian and the NS magnetosphere (NSM) rotational frequencies. The difference of the squares of the hybrid and Keplerian frequencies should tend to be almost constant in observations of kiloherth quasiperiodic oscillations (QPO). We find that for a number of sources (as we illustrate for Sco X-1, 4U1608-52 and 4U 1702-429) where the variable peak separation between the two kHz QPO peaks has been observed is well consistent with this hypothesis of the splitting of the main (Keplerian) frequency by the NSM rotation. The detection of these two KQPO frequencies along with the oscillation frequency during the burst would allow to measure the NS spin and NSM frequencies and consequently by comparing these frequencies to determine the depth of the NS potential well (or the NS radius) with a great accuracy.


If the author provided an email address or URL for general inquiries, it is as follows:

titarchuk@lheavx.gsfc.nasa.gov


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