相关论文: Is Her X-1 a strange star?

Systematic error in calculation of z for high redshift type Ia supernovae could help explain unexpected luminosity values that indicate an accelerating rate of expansion of the universe.

We review recent results obtained from observations of Anomalous X-ray Pulsars at different wavelengths (X-rays, Optical, IR and Radio) with particular emphasis on results obtained by BeppoSAX. Proposed models for AXPs are briefly presented…

Here, we explore some peculiar orbital features of the recently discovered asteroid A/2017 U1, which is a clear outlier when considering the average value of the eccentricity of known hyperbolic comets. As for the orientation of its orbit…

We have proposed the new explanation of some magnetic chemically peculiar (MCP) stars anomalies, which is based on assumption that such stars can be the close binary systems with a secondary component being neutron star. Within this…

We present Chandra and HST observations of the ultraluminous X-ray source (ULX) IC 342 X-1. The Chandra and HST images are aligned using two X-ray emitting foreground stars. The astrometry corrected position for X-1 is R.A. = 03h45m55.61s,…

Within the realms of the possibility of solid quark matter, we fitted the 500ks Chandra LETG/HRC data for RX J1856.5-3754 with a phenomenological spectral model, and found that electric conductivity of quark matter on the stellar surface is…

We report evidence of type-I X-ray bursting activity from the transient 1RXS J170930.2-263927 when it was in outburst early 1997. This identifies the source as a probable low-mass X-ray binary containing a neutron star. The error boxes of…

M40 has always been something of an oddity in the Messier Catalogue, since it is just a pair of stars rather than an extended object. Doubts have also been expressed as to whether it is even a physical binary. Here, we note that the…

During the last few years a class of enigmatic sub-luminous accreting neutron stars has been found in our Galaxy. They have peak X-ray luminosities (2-10 keV) of a few times 1E34 erg/s to a few times 1E35 erg/s, and both persistent and…

Early-type stars appear to be a difficult place to look for planets astrometrically. First, they are relatively heavy, and for fixed planetary mass the astrometric signal falls inversely as the stellar mass. Second, they are relatively rare…

LS I +61 303 is a puzzling object detected from radio up to high-energy gamma-rays. Variability has recently been observed in its high-energy emission. The object is a binary system, with a compact object and a Be star as primary. The…

Chemically peculiar (CP) stars are main-sequence A and B stars with abnormally strong or weak lines for certain elements. They generally have magnetic fields and all observables tend to vary with the same period. Chemically peculiar stars…

This article demonstrates that the recent proof of the invariant subspace problem, as presented by Khalil et al., is incorrect.

Current models and observations of variability in HgMn stars disagree. We present here the models that argue for pulsating HgMn stars with properties similar to those of Slowly Pulsating B Stars. The lack of observed variable HgMn stars…

gamma-Cas stars constitute a subgroup of Be stars showing unusually hard and bright X-ray emission. In search for additional peculiarities, we analyzed the TESS lightcurves of 15 gamma-Cas analogs. Their periodograms display broad frequency…

RR Lyrae stars are of great importance for investigations of Galactic structure. However, a complete compendium of all RR-Lyraes in the solar neighbourhood with accurate classifications and coordinates does not exist to this day. Here we…

Astrophysicists distinguish between three different types of compact stars. These are white dwarfs, neutron stars, and black holes. The former contain matter in one of the densest forms found in the Universe. This feature, together with the…

Hercules X-1/HZ Hercules (Her X-1/HZ Her) is an X-ray binary monitored by multiple X-ray missions since last century. With the abundance of long-term observations, we present a complete set of orbital light-curves of Her X-1/HZ Her during…

Investigation on open questions about perturbation of Hermitian sequences and their spectral symbols. Results on normal sequences are also furnished.

We discuss possible scenarios for the existence of strange matter in compact stars. The appearance of hyperons leads to a hyperon puzzle in ab-initio approaches based on effective baryon-baryon potentials but is not a severe problem in…