ar X iv : a st ro - p h / 04 05 59 9 v 1 2 9 M ay 2 00 4 Self lensing effects for compact stars and their mass - radius relation

ar X iv : a st ro - p h / 04 05 59 9 v 1 2 9 M ay 2 00 4 Self lensing effects for compact stars and their mass - radius relation August 20 , 2010

During the last couple of years astronomers and astrophysicists have been debating on the fact whether the so called ‘strange stars’ stars made up of strange quark matter, have been discovered with the candidates like SAX J1808.4−3658, 4U 1728−34, RX J1856.5−3754, etc. The main contention has been the estimation of radius of the star for an assumed mass of ∼ 1.4M⊙ and to see whether the point o...

ar X iv : a st ro - p h / 04 05 53 6 v 1 2 7 M ay 2 00 4 To appear in ApJ 9 / 04 A Minimum - Mass Extrasolar Nebula

By analogy with the minimum-mass solar nebula, we construct a surfacedensity profile using the orbits of the 26 precise-Doppler planets found in multiple-planet systems: Σ = 2200 g cm (a/1 AU), where a is the circumstellar radius and β = 2.0 ± 0.5. The minimum-mass solar nebula (β = 1.5) is consistent with this model, but the uniform-α accretion disk model (β ≈ 1) is not. In a nebula with β > 2...

ar X iv : a st ro - p h / 04 05 50 0 v 1 25 M ay 2 00 4 Potential Direct Single - Star Mass Measurement

We analyze the lightcurve of the microlensing event OGLE-2003-BLG175/MOA-2003-BLG-45 and show that it has two properties that, when combined with future high resolution astrometry, could lead to a direct, accurate measurement of the lens mass. First, the lightcurve shows clear signs of distortion due to the Earth’s accelerated motion, which yields a measurement of the projected Einstein radius ...

ar X iv : a st ro - p h / 02 05 14 4 v 1 9 M ay 2 00 2 X - ray Rich GRB , Photospheres and Variability

We investigate the relationship between the quasi-thermal baryon-related photosphere in relativistic outflows, and the internal shocks arising outside them, which out to a limiting radius may be able to create enough pairs to extend the optically thick region. Variable gamma-ray light curves are likely to arise outside this limiting pair-forming shock radius, while X-ray excess bursts may arise...

ar X iv : h ep - p h / 04 05 11 9 v 1 1 3 M ay 2 00 4 The Lorentz and CPT violating effects on the charged