Related papers: Deuterium burning in objects forming via the core …
Compact astrophysical objects, such as neutron stars and white dwarfs, can act as detectors of energetic particle fluxes originating from astrophysical accelerators. While most existing capture and heating calculations assume isotropic very…
We present self-consistent calculations coupling numerical hydrodynamics simulations of collapsing pre-stellar cores and stellar evolution models of accreting objects. We analyse the main impact of consistent accretion history on the…
Galactic destruction of primordial deuterium is inevitably linked through star formation to the chemical evolution of the Galaxy. The relatively high present gas content and low metallicity suggest only modest D-destruction. In concert with…
To date, hundreds of sub-stellar objects with masses between $1-80\ M_{\rm Jup}$ have been detected orbiting main-sequence stars. The current convention uses the deuterium-burning limit, $M_c \approx 13 M_{\rm Jup}$ to divide this…
High levels of deuterium fraction in N$_2$H$^+$ are observed in some pre-stellar cores. Single-zone chemical models find that the timescale required to reach observed values ($D_{\rm frac}^{{\rm N}_2{\rm H}^+} \equiv {\rm N}_2{\rm D}^+/{\rm…
We address the formation of correlations in a general nonequilibrium situation. As an example we calculate the formation of light composite particles in a heavy ion collision. In particular we study the formation of deuterons via three-body…
We investigate the mass function in the substellar domain down to a few Jupiter masses in the young sigma Orionis open cluster (3+/-2 Ma, d = 360^+70_-60 pc). We have performed a deep IJ-band search, covering an area of 790 arcmin^2 close…
The continuous temporal coverage and high photometric precision afforded by space observatories has opened up new opportunities for the study of variability processes in young stellar cluster members. Of particular interest is the…
(Abridged) We aim to determine the degrees of CO depletion, deuterium fractionation, and ionisation in a sample of seven massive clumps associated with IRDCs. The APEX telescope was used to observe the C17O(2-1), H13CO+(3-2), DCO+(3-2),…
A key outstanding question in star and planet formation is how far the initial mass function of stars and sub-stellar objects extends, and whether or not there is a cut-off at the very lowest masses. Isolated objects in the planetary-mass…
Recent theoretical work has shown that the pre-main-sequence (PMS) evolution of stars is much more complex than previously envisioned. Instead of the traditional steady, one-dimensional solution, accretion may be episodic and not…
One of the challenges to increasing the mass of a white dwarf through accretion is the tendency for the accumulating hydrogen to ignite unstably and potentially trigger mass loss. It has been known for many years that there is a narrow…
Comet--asteroid transition (CAT) objects are small solar system bodies in the process of evolving from cometary nuclei into asteroids, as they gradually lose volatile substances due to solar heating. The volatile material is mainly water…
Nuclear burning and its dependence on the mass accretion rate are fundamental ingredients for describing the complicated observational phenomenology of neutron stars in binary systems. Motivated by high quality burst rate data emerging from…
The relative abundance of deuterium and hydrogen is a potent tracer of planet formation and evolution. Jupiter and Saturn have protosolar atmospheric D/H ratios, a relic of substantial gas accretion from the nebula, while the atmospheres of…
We consider the role of deuterium as a potential marker of location and ambient conditions during the formation of small bodies in our Solar system. We concentrate in particular on the formation of the regular icy satellites of Jupiter and…
The evolution of low- and intermediate mass stars at the onset and during core helium burning is reviewed. Particular emphasis is laid on structural differences, which may allow to identify a star's nature and evolutionary phase in spite of…
A new cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation…
We investigate the impacts of nuclear burning on the spherically symmetric stationary accretion flow of helium-rich matter on to compact objects. We have already shown the existence of the critical accretion rates for the accretion of…
The accurate evaluation of the nuclear reaction rates and corresponding uncertainties is an essential requisite for a precise determination of light nuclide primordial abundances. The recent measurement of the D(p,gamma)3He radiative…