The formation of habitable planets in the four-planet system HD 141399

ABSTRACT The presented work investigates the possible formation of terrestrial planets in the habitable zone (HZ) of the exoplanetary system HD 141399. In this system, the HZ is located approximately between the planets c (a = 0.7 au) and d (a = 2.1 au). Extensive numerical integrations of the equations of motion in the pure Newtonian framework of small bodies with different initial conditions in the HZ are performed. Our investigations included several steps starting with 500 massless bodies distributed between planets c and d in order to model the development of the disc of small bodies. It turns out that after some 106 yr, a belt-like structure analogue to the main belt inside Jupiter in our Solar system appears. We then proceed with giving the small bodies masses (∼ Moon mass) and take into account the gravitational interaction between these planetesimal-like objects. The growing of the objects – with certain percentage of water – due to collisions is computed in order to look for the formation of terrestrial planets. We observe that planets form in regions connected to mean motion resonances (MMR). So far there is no observational evidence of terrestrial planets in the system of HD 141399 but from our results we can conclude that the formation of terrestrial planets – even with an appropriate amount of water necessary for being habitable – in the HZ would have been possible.

A computational study of quantum transport properties of hydrogen passivated graphene monoxide: NDR and rectification

We computed the electronic transport properties of a structure analogue to graphene monoxide using combining non-equilibrium Green’s function and density functional theory methods. These properties were transmission spectrum and current – bias voltage characteristics, along with density of states and projected density of states of the electrodes and central molecules. We found that the computed current values in considered bias potentials had the rectification behavior and included a negative differential resistance region. We interpreted these properties using the relative localization and delocalization of molecular projected self-consistent Hamiltonian orbitals.

A Data Structure Analogue for Modelling Tree Crowns

A rooted-tree computer data structure is used as an analogue of coniferous tree crowns in building a simulation model of a single tree. Submodels of branch death and the allocation of stored reserves are used to illustrate the model. The programming language used is PL/1.