The Theory of Brown Dwarfs and Extrasolar Giant Planets

Straddling the traditional realms of the planets and the stars, objects below the edge of the main sequence have such unique properties, and are being discovered in such quantities, that one can rightly claim that a new field at the interface of planetary science and and astronomy is being born. In this review, we explore the essential elements of the theory of brown dwarfs and giant planets, as well as of the new spectroscopic classes L and T. To this end, we describe their evolution, spectra, atmospheric compositions, chemistry, physics, and nuclear phases and explain the basic systematics of substellar-mass objects across three orders of magnitude in both mass and age and a factor of 30 in effective temperature. Moreover, we discuss the distinctive features of those extrasolar giant planets that are irradiated by a central primary, in particular their reflection spectra, albedos, and transits. Aspects of the latest theory of Jupiter and Saturn are also presented. Throughout, we highlight the effects of condensates, clouds, molecular abundances, and molecular/atomic opacities in brown dwarf and giant planet atmospheres and summarize the resulting spectral diagnostics. Where possible, the theory is put in its current observational context.Comment: 67 pages (including 36 figures), RMP RevTeX LaTeX, accepted for publication in the Reviews of Modern Physics. 30 figures are color. Most of the figures are in GIF format to reduce the overall size. The full version with figures can also be found at: http://jupiter.as.arizona.edu/~burrows/papers/rm

Stark broadening data for spectral lines of rare-earth elements: Example of Tb II and Tb IV

International audienc

70 years of Astronomical society “Rudjer Bošković” – an interesting experience in astronomical education, popularization and organization of astronomer amateurs

The oldest organization of astronomers amateurs in Serbia is the Astronomical society “Rudjer Bošković” which in 2004. celebrates the 70th aniversary. The Society has People's observatory which in 2004 celebrates 40th jubilly, planetarium and publish the journal for astronomy “Vasiona” (Universe), which 50th aniversary has been celebrated in 2003. Here is given a review of the history and development of Society and an overview of its activities

Stark broadening data tables for some analogous spectral lines along Li and Be isoelectronic sequences

By using the semiclassical perturbation approach, Stark broadening parameters due to the interaction with a selection of perturbers of interest for recently published experimental results for Li - like B III, C IV, N V and O VI 3s2S-3p2Po, and for Be - like B II, C III, N IV and O V 3s3S-3p3Po multiplets, have been calculated. The results are presented as a function of temperature for a perturber density of 1017cm−3. The influence of resonance contribution for B II, differences in Stark broadening parameters if we take oscillator strengths calculated within the Coulomb approximation or taken from TOP Database, and the influence of transitions with different parent terms, have been discussed as well

Estimation of electron-impact line widths for singly-, doubly- and triply-charged vanadium ions

In this paper we present the electron-impact widths for 28 transitions of singly-, doubly-, and triply- ionized vanadium estimated by using the modified semiempirical method. The electron-impact widths have been estimated for the electron density of 1023m−3 and presented as a function of electron temperature

A MODIFIED ADIABATIC THEORY CALCULATION FOR THE STARK BROADENING OF He I (31P0-21S)

Curvilinear trajectory adiabatic approxination for calculating Stark broadening parameters for neutral lines from plasmas, as proposed by authors,1,2 has been applied to HeI(31p0-21S ) line, at T = 5000. K and Ne=1015cm-3. This line has been chosen for two reasons: (1) The quadrupole perturber-emitter interaction potential is much smaller than corresponding dipole polarization interaction, so that simple analytical calculations can be carried out; (2) Stark constant C4 of the upper level of the transition is negative and large, so that so called defocusing effect can be distinctly demonstrated

Life and activities of Vasilije Oskanjan (1921-1989)

The life and scientific, professional and other activities of Vasilije Oskanjan (1921-1989), one-time director of the Belgrade Astronomical Observatory, research fellow of the Belgrade and Byurakan Observatories, are presented, followed by the Bibliography of his works, the list of bibliographical items wherein his name is mentioned and the list of his name’s citations in the Science Citation Index in the period 1946 - July 1999

Influence of the (n-n')-mixing processes on the optical properties of the hydrogen clouds in the broad-line region of AGNs

International audienc

Quantum Stark broadening of Ar XV lines. Strong collision and quadrupolar potential contributions

International audienc

Stark broadening of B I spectral lines within 2s22p - 2s2nd Spectral Series

International audienc