The cometary activity of Centaur P/2004 A1 (LONEOS)★

comparison of catalytic activity of heteropoly compounds in the synthesis of bis(indolyl)alkanes.

heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...

Using Cometary Activity to Trace the Physical and Chemical Evolution of Cometary Nuclei

Historically, minor bodies are classified as comets based on observations of “activity,” which refers to the appearance of dust and gas around the nucleus. While cometary activity has been observed for centuries, at ever-increasing heliocentric distances, our understanding of the mechanisms for producing cometary activity and its heliocentric dependence has only recently been developed to the l...

Anatomy of the Centaur Historical Background

A staple of Greek mythology, Centaurs have made many appearances throughout the centuries and even in our own time. They are represented by numerous sculptures and images in museums. True, when speaking of Centaurs, we have to rely on twoand three-dimensional models—here as many other instances in biology—because there has not yet been a sighting of a live specimen. However, the majority of ext...

CentAUR Central

CentAUR Central

Many recent papers have documented the existence of periodicities in returns, return volatility, bidask spreads and trading volume, in both equity and foreign exchange markets. In this paper, we propose and employ a new test for detecting subtle periodicities in time-series data based on a signal coherence function. The technique is applied to a set of seven half-hourly exchange rate series. Ov...