The results of observations of the two SNRs HB 9 and IC 443 are discussed. A map of HB 9 is presented whose main features are an elongation in the northerly direction and a strong region at the center of the map. The ...

We put forward evidence that relates the phenomenon of the chemically peculiar stars of the upper main sequence to Supernovae explosions in young clusters. In the Upper Scorpius region we find that a supernova shell has ...

UBV photometry of HR 1099 obtained during the 1979-80 and 1980-81 observing seasons is presented. An analysis of the available data shows that the brightness at the light curve maximum increases as the wave amplitude ...

B and V photometry of HD 81410 obtained on 34 nights between January 3 and March 14 of 1981 is presented. In both B and V, the amplitudes are found to be approximately 0.15 mag. It is also found that a 12.86833 day period ...

It is observed that the rotational velocities of most Ap stars are dependent on their masses. Deviations from this general rule may be explained in terms of multiplicity which affects the derived colors and radii. Spectroscopic ...

A classification scheme is proposed for the central regions of Sérsic-Pastoriza galaxies based on high resolution photographs of 50 objects in the integrated light (4000 Å-8700 Å). Structures of two different linear scales ...

The nucleus of NGC 2903 is identified on near infrared photographs. The energy distribution of this nucleus in the visual region of the spectrum is estimated from available observations. The continuum compares well with ...

An initial stationary flow in a configuration diverging as r-squared is assumed, a state corresponding to the normal solar wind solution. The effect on the flow through a tube whose area A(r, t) diverges faster than ...

Mathematical modelling is used in determining the rotational frequency and the density of an ionized medium. It is noted that the technique derives from the measurement of the group travel time for a wave propagating in a ...