Related papers: A quest for weak objects and for invisible stars
Observations by the MACHO collaboration suggest that a significant proportion of the galactic halo dark matter is in the form of compact objects with typical masses $M\sim 0.5M_{\odot}$. One of the current mysteries is the nature and origin…
This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts,…
White dwarfs are a class of stars with unique physical properties. They present many challenging problems whose solution requires the application of advanced theories of dense matter, state-of-the-art experimental techniques, and extensive…
The nature of the Massive Compact Halo objects seen in microlensing experiments and interpreted as dark matter in the Halo of our Galaxy remains a mystery. Arguments are presented that these events are probably not ordinary stellar or…
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 which, together with the…
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…
White dwarfs are among the most common objects in the stellar halo; however, due to their low luminosity and low number density compared to the stars in the discs of the Milky Way, they are scarce in the observable volume. Hence, they are…
Macroscopic dark matter -- "macros"-- refers to a broad class of alternative candidates to particle dark matter with still unprobed regions of parameter space. These candidates would transfer energy primarily through elastic scattering with…
Imaging and spectroscopic observations in the mid-infrared wavelength range (5$\mu$m--30$\mu$m) offer valuable insight into the origins of stars and planets. Sensitive new array detectors on 8-meter class telescopes make it possible to…
Using data derived from the deepest and finest angular resolution images of the universe yet acquired by astronomers at optical wavelengths using the Hubble Space Telescope (HST) in two postage-stamp sections of the sky (Williams et al.…
We examine 14 hot white dwarfs for signs of infrared excess using the Spitzer Space Telescope. Twelve of the objects are massive white dwarfs which have been suggested to be the result of binary mergers. The remaining two objects are…
A straightforward interpretation of the MACHO microlensing results in the direction of the Magellanic Clouds suggests that an important fraction of the baryonic dark matter component of our Galaxy is in the form of old white dwarfs. If…
White dwarfs are the remnants of stars not massive enough to become supernovae. This review explores the concept of strange dwarfs, a unique class of white dwarfs which contain cores of strange quark matter. Strange dwarfs have different…
Dark matter is thought to make up most of the matter density of the Universe, yet its true nature remains uncertain. Among dark matter theories, Weakly Interacting Massive Particles (WIMPs) are a prominent candidate for dark matter because…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
Our ongoing spectroscopic survey of high proper motion stars is a rich source of new magnetic white dwarfs. We present a few examples among cool white dwarfs showing the effect of field strength and geometry on the observed optical…
This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts,…
The one billion objects in the GSC-II make up a formidable data set for the hunt of peculiar and rare targets such as late type stars, white dwarfs, carbon dwarfs, asteroids, variable stars, etc. Here we present a survey to search for…
We construct infrared star count models of the Galaxy applicable at faint magnitudes. In addition to dwarfs and subdwarfs, we also take into account L dwarfs, T dwarfs, and white dwarfs of both disk and halo. As a test case of the models,…
Microlensing observations have now become a useful tool in searching for non--luminous astrophysical compact objects (brown dwarfs, faint stars, neutron stars, black holes and even planets). Originally conceived for establishing whether the…