A spectroscopic study of Wolf-Rayet stars

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Spectroscopic Study of Amethyst Quartz in the Ultraviolet and Infrared Regions

In this paper a study is made of the Absorption of light in the ultraviolet and infrared regions in amethyst quartz. In the ultraviolet the presence of the T-band is masked by the presence of iron impurity and it is difficult to assert its presence. That such a P-band exists was shown by Choong. In the near infrared three absorption bands arc observed the one on the long wavelength side ran be identified with the M-band and the others as bands due to impurity. MI these facts lead to the conclusion that the factors responsible for colour in the case of coloured alkali halides are also responsible for the coloration of amethyst quartz, with some slight difference

A photoelectric study of early-type supergiants around h and χ Persei

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Magnitudes and colours of some members of the Perseus cluster

Photoelectric colours and magnitudes have been determined for twenty-five stars considered to be members of the moving cluster in Perseus. A distance modulus of 6m.83, corresponding to a distance of 230 ps, has been derived. This value is nearly twice the value of 120 ps derived by Miss Roman and Morgan from the upsilon component of proper motion

Polarization of comet Arend-Roland

When, last May, Comet Arend-Roland became a bright naked-eye object in the northern hemisphere, we carried out a series of photoelectric measures of the polarization of its coma at different phase angles. The technique employed utilized a piece of 'Polaroid' attached to a rotatable six-position disk contained in the photometer. This enables measurements of intensity to be made as the 'Polaroid' is turned through 60 dog. for each position of the disk. Standard B and V filters employed in the UBV system, together with interference filters having peak transmissions centred on 5890 A., 5000 A., 4700 A. and 4300 A. and half-widths of 80 A. were used for isolating the different wave-lengths. Each of the three circular apertures behind the 'Polaroid' transmitted 3.7 square minutes of arc of the sky

Emission-line profiles from expanding envelopes

We have developed a method for calculating the emission-line profiles from an expanding envelope. The method applies to an envelope where the emission intensity varies with latitude. Some typically illustrative cases are considered