\Vhen a,massive star collapses to a neutron star, rapidly losing over half its mass in a symmetric supernova explosion, any planets orbiting the star will be unbound. ]Iowever, to explain the observed space velocity and binary fraction of radio pulsars, an asymmetric kick must be given to the neutron star at birth. Occasionally, this kick will prevent the resulting pulsar-planet system from unb...

This paper is directed to the question of how to model and design an efficient tool for the intelligent mapping which is based on both dynamic and efficient storage of data and soft computing. The former is performed by our method that learns how to store, search and delete the data. After pointing out the limitation of the crisp evaluation of the distance between two points, we argue in favor ...

We report the discovery of a 16 th magnitude star, HE 0437−5439, with a heliocentric radial velocity of +723 ± 3 km s −1. A quantitative spectral analysis of high-resolution optical spectra obtained with the VLT and the UVES – 2 – spectrograph shows that HE 0437−5439 is a main sequence B-type star with T eff =20 350 K, log(g) = 3.77, solar within a factor of a few helium abundance and metal con...

Groundand space-based observations of stellar heavy element abundances are providing a clearer picture of the chemical evolution of the Galaxy. A large number of (r)apid and (s)low neutron capture process elements, including the first Hubble Space Telescope observations of Pt, Os, Pb and Ge, have been identified in metal-poor, galactic halo stars. In the very low metallicity (i.e. [Fe/H] < –2.0...

A 3D quasiperiodic pattern by projection from an nD lattice can be defined by an orthonormal n x n lattice matrix which produces basis vectors in pattern space with a prescribed arrangement and basis vectors in perpendicular or test space satisfying the quasicrystallographic condition. A 16 x 16 lattice matrix is derived which produces basis vectors in pattern space as a combination or mixing o...

We have analyzed the kinematical parameters of Cir X-1 to constrain the nature of its companion star, the eccentricity of the binary and the pre-supernova parameter space. We argue that the companion is most likely to be a low-mass (∼ 2.0M⊙) unevolved star and that the eccentricity of the orbit is 0.94 ± 0.04. We have evaluated the dynamical effects of the supernova explosion and we find it mus...

After 3 years of quiescence, the globular cluster NGC 6440 exhibited a bright transient X-ray source turning on in August 2001, as noted with the RXTE AllSky Monitor. We carried out a short target of opportunity observation with the Chandra X-ray Observatory and are able to associate the transient with the brightest of 24 X-ray sources detected during quiescence in July 2000 with Chandra. Furth...