Broad-band optical and infrared observations in the R, I, and J, H, Ks bands of comet McNaught-Hartley (C/1999 T1) were performed from Jan. 25 to Feb. 4, 2001, shortly after the comet perihelion on Dec. 14, 2000. For the time the comet was observed, it did not show any peculiar behaviour either in the infrared or in the optical, that is, no non

We report on the discovery of variable circular polarization from the remnant of Nova Chamaeleontis 1953 (RR Cha). The circular polarization appears to be modulated on the spin period of the primary and harmonics of the positive superhump period, with an amplitude peak-to-peak of almost ~10 per cent with both negative and positive polarization. A

We constrain the basic cosmological parameters using the first observations by the Very Small Array (VSA) in its extended configuration, together with existing cosmic microwave background data and other cosmological observations. We estimate cosmological parameters for four different models of increasing complexity. In each case, careful

In this paper, we present a study of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni in a large set of stars known to harbor giant planets, as well as in a comparison sample of stars not known to have any planetary-mass companions. We have checked for possible chemical differences between planet hosts and field stars without known planets

We have obtained a new, deep, wide-field optical imaging survey of the young Alpha Persei cluster which reveals a well-populated lower main sequence extending into the substellar mass regime. Subsequent infrared photometry confirms that most of the candidate brown dwarfs are indeed likely to be cluster members, with a predicted minimum mass of

We present clear evidence for the motion of the companion star in the low-mass X-ray binary (LMXB) X1822-371. We detect N III λ4640 emission moving in antiphase with the radial velocity curve of the neutron star and produced on the X-ray-heated hemisphere of the donor star. From the motion of this feature we derive a lower limit to the radial