Pyrolysis of immature Torbanite and of the resistant biopolymer (PRB A) isolated from extant alga Botryococcus braunii. Mechanism of formation and structure of torbanite

Immature Torbanite and the resistant biopolymer (PRB A) isolated from extant B. braunii were previously compared using bulk spectroscopic methods. In the present work, analysis of 400°C pyrolysis products and pyrolysis residues provided further information on their structure and possible relationships. It appears that such polymers are based upon unbranched, saturated, cross-linked hydrocarbon chains up to C₃₁. In addition to these bridging structures, a substantial part of the alkyl chains is singly bound, as esters of unbranched, saturated or cis unsaturated, even fatty acids. These esters are sterically protected, against chemical degradations, by the network of the bioand geopolymer.Quantitative and qualitative observations derived from 400°C pyrolysis confirm that the chemical structure of PRB A and immature Torbanite are closely related. The pyrolysis residues show a similar evolution and numerous common features are noted, with respect to the nature and the distribution of the major constituents of the pyrolysates (hydrocarbons and fatty acids). Accordingly, Botryococcus provides what seems to be the first example of a close structural relationship between a biopolymer produced in large amounts by an extant alga and the geopolymer of an immature kerogen. The essential role of PRB A in Torbanite formation is ascertained. Moreover, it is found that the resistant biopolymer does not undergo important structural changes during the first stages of diagenesis. Thus, owing to steric protection, the esters of immature Torbanite show a distribution quite close to the one of PRB A esters, with exclusively even constituents and a large contribution of unsaturated acids.Recent observations pointed to the possible genesis of some algal kerogens principally by selective preservation of resistant macromolecules. Such a type of formation is clearly predominant in Torbanite, where the bulk of the fossil organic matter corresponds to a selectively preserved and weakly altered, resistant biopolymer, while incorporation of lipids into the kerogen structure during diagenesis seems to play a minor role.     

UBV observation and analysis of VV Orionis

TheUBV photoelectric observation of the eclipsing binary star VV Ori were made at Al-Battani Observatory, Baghdad, Iraq, during nine nights in November and December, 1984 and January, 1985. As a result, three light curves were completed.An analysis of theB andV normal points light curves using the optimization method shows the existence of a slight shift in the primary mid-minimum epoch and the temperature of the secondary component is consistent with B5-type star. A new set of geometrical and physical elements is also presented.     

IUE observations of certain short period RS CVn-like stars

Nine low and one high resolution IUE (LWR) spectrograms for the short period subgroup RS CVn-like stars have been studied, particularly in connection with the MgII 2800 Å feature. Clear emission contributions can be easily seen for some of these stars, while all nine of them appear to have the feature filled by emission to some extent.If surface flux in emission is considered as a measure of activity (and not just equivalent width) the short period subgroup is as active as the main group. The activity is not as obvious because of the generally higher photospheric temperatures.Correlations of such activity with angular velocity and the scale of irregular photometric distortions (starspots) are present, though the sample size is low.