Aims: Precise determination of the stellar effective temperature of solar type stars is extremely important for astrophysics. We present an effective temperature calibration for FGK dwarf stars using the line equivalent width ratios of spectral absorption lines. Methods: We used the automatic code ARES to measure the equivalent width for several

We present the most complete atlas of nuclear rings to date. We include 113 rings found in 107 galaxies, six of which are elliptical galaxies, five are highly inclined disc galaxies, 18 are unbarred disc galaxies and 78 are barred disc galaxies. Star-forming nuclear rings occur in 20 +/- 2 per cent of disc galaxies with types between T = -3 and T =

Of the over 400 known exoplanets, there are about 70 planets that transit their central star, a situation that permits the derivation of their basic parameters and facilitates investigations of their atmospheres. Some short-period planets, including the first terrestrial exoplanet (CoRoT-7b), have been discovered using a space mission designed to

C60 fullerene can be easily hydrogenated in aromatic solvent under mild conditions with aqueous hydrogen iodide (HI). The resulting black product has the molecular formula C60H24 center dot 2I2 on the basis of the FT-IR spectroscopy and of the thermogravimetric analysis. When this compound is heated under N2 it releases I2 and HI producing

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Three years of optical monitoring of the low-mass X-ray binary (LMXB) 4U 1957+11 is presented. The source was observed in V, R and i bands using the Faulkes Telescopes North and South. The light curve is dominated by long-term variations which are correlated (at the >3σ level) with the soft X-ray flux from the All Sky Monitor on board the Rossi X