13 research outputs found
A giant exoplanet orbiting a very-low-mass star challenges planet formation models
Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought
Bacterial enzymes and multi-enzymatic systems for cleaning-up dyes from the environment
Synthetic dyes are xenobiotic compounds that are being increasingly used in several industries, with special emphasis in the paper, textile and leather industries. Over 100,000 commercial dyes exist today and more than 7 Ă 105 tons of dyestuff is produced annually, of which 1â1.5 Ă 105 tons is released into the wastewaters (Rai et al in Crit Rev Environ Sci Tecnhol 35:219â238, 2005). Among these, azo dyes, characterized by the presence of one or more azo groups (âN=Nâ), and anthraquinonic dyes represent the largest and most versatile groups