We report optical spectroscopic observations of the radio-quiet quasar Kaz 102. We find impressive variations of the Hα emission line both in shape and intensity. Hα dimms by 40%, and develops a blue asymmetry within a few years. The continuum level also decreases by a similar amount. We discuss the results in terms of the kinematics of the BLR

We present new results from a study of recent cosmic microwave background (CMB) observations which provide the first strong evidence for the existence of a 'Doppler peak' localized in both angular scale and amplitude. This first estimate of the angular position of the peak is used to place a new direct limit on the curvature of the universe

We have studied the statistical properties of the energy of individual acoustic modes, extracted from 310 days of GOLF data near the solar minimum. The exponential distribution of the energy of each mode is clearly seen. The modes are found to be uncorrelated with a partial 0.6% accuracy, thus supporting the hypothesis of stochastic excitation by

We examine the status of the threat posed to stellar-mass black hole candidates by the possible existence of Q-stars (compact objects with an exotic equation of state that might have masses well above the normally accepted maximum for standard neutron stars). We point out that Q-stars could be extremely compact (with radii less than 1.5 times the

I report medium-resolution spectroscopic observations of six H emission-line stars proposed by Meyer et al. (1993) to be T Tauri stars formed in the vicinity of the B1 giant Sco, a bright member of the Sco-Cen OB association. Using spectroscopic criteria which are distance-independent, I classify these stars in different premain-sequence (PMS)

The physics of a twisted magnetic flux tube rising in a stratified medium is studied using a numerical MHD code. The problem considered is fully compressible (no Boussinesq approximation), includes ohmic resistivity, and is two dimensional, i.e., there is no variation of the variables in the direction of the tube axis. We study a high plasma beta