The neutron vortices thought to exist in the inner crust of a neutron star interact with nuclei and are expected to pin to the nuclear lattice. Evidence for long-period precession in pulsars, however, requires that pinning be negligible. We estimate the strength of vortex pinning and show that hydrodynamic forces present in a precessing star are likely sufficient to unpin all of the vortices of...

While conducting a near-infrared (NIR) survey of “Digel Clouds”, which are thought to be located in the extreme outer Galaxy (EOG), Kobayashi & Tokunaga found star formation activity in “Cloud 2”, a giant molecular cloud at the Galactic radius of ∼ 20 kpc. Additional infrared imaging showed two embedded young clusters at the densest regions of the molecular cloud. Because the molecular cloud is...

We present a chemical composition analysis of 36 giant stars in mildly metal-poor globular cluster M5. In comparing the M5 results to those obtained in M4, a cluster previously considered to be a “twin” in age, metallicity and chemical composition, we find large star-to-star variations in the abundances of elements sensitive to proton-capture nucleosynthesis, similar [Fe/H] values, but factor o...

Exo-planet migration is assumed to have occurred to explain close-to-star gas giant exoplanets within the context of the so-called standard model of solar system formation, rather than giving cause to question the validity of that particular model. I present evidence against the concept of planet migration, evidence that is historical, interdisciplinary, and model-independent. First, I demonstr...

We use Subaru Suprime-Cam and VLT FORS1 photometry of the dwarf galaxy DDO210 to study the global stellar content and structural properties of a transitiontype galaxy (with properties intermediate between dwarf irregular and dwarf spheroidal systems). This galaxy is sufficiently isolated that tidal interactions are not likely to have affected its evolution in any way. The colour-magnitude diagr...

We describe a phenomenological model for molecular hydrogen formation suited for applications in galaxy formation simulations, which includes non-equilibrium formation of H2 on dust and approximate treatment of both its self-shielding and shielding by dust from the dissociating UV radiation. The model is applicable in simulations in which individual star forming regions – the giant molecular co...

Astronomers have established that for a few million years newborn stars possess disks of orbiting gas and dust. Such disks, which are likely sites of planet formation, appear to disappear once these stars reach ages of 5-10 × 10 yr; yet, ≥ 10 yr is thought necessary for giant planet formation. If disks dissipate in less time than is needed for giant planet formation, such planets may be rare an...

I study some aspects of common envelope evolution, where a compact star enters the envelope of a giant star. I show that in some binary systems under a narrow range of parameters, a substantial fraction of the giant stellar envelope is lost before the onset of the common envelope. The reduced envelope mass at the onset of the common envelope implies that the binary system emerges from the commo...

Context. The discovery of a short-period giant planet (a hot Jupiter) around the primary component of the triple star system HD 188753 has often been considered as an important observational evidence and as a serious challenge to planet-formation theories. Aims. Following this discovery, we monitored HD 188753 during one year to better characterize the planetary orbit and the feasibility of pla...

Two UV brights stars in globular clusters, ROA 5701 (ω Cen) and Barnard 29 (M 13) are analysed from highresolution UV and optical spectra. The main aim is the measurement of iron abundances from UV spectra obtained with the HST-GHRS. In addition atmospheric parameters and abundances for He, C, N, O, and Si are derived from optical spectra (ESO CASPEC) for ROA 5701 or taken from literature for B...