A population of small main-belt asteroids residing on closely similar orbits was revealed by Vokrouhlicky and Nesvorny (2008, Astron. J. 136, 280-290). We have estimated statistical significances of individual pairs (Pravec and Vokrouhlicky 2009, Icarus, in press) and started a photometry observing program to characterize their spin properties

The requirements for current large and future extremely large telescopes as well as the quick development of IR instrumentation demand a proper characterization of precipitable water vapour (PWV) above astronomical sites. A comparison of PWV estimations from a photometer and a GPS (Global Positioning System) above the Observatorio del Roque de los

Airglow in a planetary atmosphere is diagnostic of the combined effects of transport, both vertical and horizontal, and chemistry. Airglow emission on the night side in the OH(3-2, 2-1, 2-0, and 1-0), O2(c-X and a-X), and NO(C-A) bands has been reported in the past two years based on observations by VIRTIS on Venus Express [1,2,3]. Previous

The electron temperatures of high-metallicity [12 + log(O/H) > 8.2] HII regions have been studied. The empirical flux-flux relations which express the nebular-to-auroral [OIII] line ratio Q3,O (as well as the nebular-to-auroral [OII] line ratio Q2,O, and the nebular-to-auroral [NII] line ratio Q2,N) in terms of the nebular R3 and R2 line fluxes in

Active galactic nuclei (AGNs) play an important role in many aspects of modern cosmology, and of particular interest is the issue of the interplay between AGNs and their host galaxy. Using X-ray and optical data sets, we have explored the properties of a large sample of AGNs in the Subaru/XMM-Newton Deep Survey field, and studied their evolution in

Context: The dependence of amplitude on the pulsation period differs from other Cepheid-related relationships. Aims: We attempt to revise the period-amplitude (P-A) relationship of Galactic Cepheids based on multi-colour photometric and radial velocity data. Reliable P-A graphs for Galactic Cepheids constructed for the U, B, V, R_C, and IC