Related papers: Is Her X-1 a strange star?
The concept of dark energy can be used as a possible option to prevent the gravitational collapse of compact objects into singularities. It affects the universe on the largest scale, as it is responsible for our universe's accelerated…
Photometrically and spectroscopically variable chemically peculiar (CP) stars are the optimum laboratories for testing the rotational evolution of main sequence stars. A vast majority of well-studied CP stars have quite steady rotational…
We have studied strange star properties both at zero temperature and at finite temperatures and searched signatures of strange stars in gamma-ray, x-ray and radio astronomy. We have a set of Equations of State (EoS) for strange quark matter…
The binary nature of the bright (V = 4.2 mag) Mercury-Manganese star Phi Her has been known since 1976 and it was considered a low-amplitude single-lined SB. In a recent study we found evidence for lines of the secondary star. Other recent…
In a recent paper, Vink et al. analyzed some spectropolarimetry data of O-type stars. Here we comment on our disagreement with some points presented in this paper, with the hope of helping to fully grasp the scientific implication of these…
A strong X-ray illumination of the optical star atmosphere in Her X-1, asymmetric because of a partial shadowing by the tilted twisted accretion disk around central neutron star, leads to the formation of matter flows coming out of the…
The unusal hard x-ray burster GRO J1744-28 recently discovered by the Compton Gamma-ray Observatory (GRO) can be modeled as a strange star with a dipolar magnetic field $\le 10^{11} $Gauss. When the accreted mass of the star exceeds some…
Structure parameters of rapidly rotating strange stars are compared with those for neutron stars. The salient differences are pointed out.
The observed SEDs of a sample of 60 OH/IR stars are fitted using a radiative transfer model of a dusty envelope. Among the whole sample, 21 stars have reliable phase-lag distances while the others have less accurate distances. L*-P,Mlr-P…
In Paul, Raichur and Mukherjee (2005) we had reported a spectral mode change in the X-ray binary pulsar Cen X-3 using the then available ASM light curves of Cen X-3. Being mindful of the fact that instrument calibration or other issues like…
Archival Hubble Space Telescope Wide Field/Planetary Camera 2 observations of the Small Magellanic Cloud serendipitously reveal a possible counterpart to the Anomalous X-ray Pulsar CXOU J010043.1-721134. The candidate is faint, but its…
Using CGS4 on UKIRT, we have obtained a 1.95-2.45 micron infrared spectrum of the primary candidate counterpart to the bright Z LMXB GX5-1. IR photometry by Naylor, Charles, & Longmore (1992) and the astrometry of Jonker et al. (2000) had…
We aim to investigate the nature of the high energy source KS 1741-293 by revisiting the radio and infrared associations proposed in the early 1990s. Our work is mostly based on the analysis of modern survey and archive data, including the…
The analysis of the central compact object within the supernova remnant HESS J1731-347 suggests that it has a small radius and, even more interestingly, a mass of the order or smaller than one solar mass. This raises the question of which…
Astronomers occasionally detect an object having unexpected shape, unexplainable photometry, or unprecedented spectra that are inconsistent with our contemporary knowledge of the universe. Upon careful assessment, many of these anomalies…
The mass-radius relations for bare and crusted strange stars are calculated with the bag model. Comparing these relations with the observed one derived from redshift, we address that the conclusion, that EXO 0748-676 can not be a strange…
While the number of stellar-mass black holes detected in X-rays or as gravitational wave sources is steadily increasing, the known population remains orders of magnitude smaller than predicted by stellar evolution theory. A significant…
The traditional method for detecting extra-solar planets relies on measuring a small stellar wobble which is assumed to be caused by a planet orbiting the star. Recently, it was suggested that a similar stellar wobble could be caused by a…
The purpose of this work is to supplement the "Stars with solar-type activity" catalog with information about confirmed exoplanets and exoplanet candidates. To do this, cross-identification of the catalog stars with data from the NASA…
This article has been withdrawn; see astro-ph/0611542