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Chen, K.-Y.

Publications and source records attributed to Chen, K.-Y..

12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

A study of the Mg II k line in Beta Persei

Spectral scans of the Mg II k line in Beta Per were obtained with Copernicus during two primary eclipses. A brief description of observation in a short frame mode is given. The observed data are compared with computed line profiles based on the eclipse geometry of spherical stars. It is shown that a nonuniform circumstellar envelope, or cloud, probably is present. In one scan, a red-shifted line of P Cygni-type profile appeared, indicating the occurrence of an unusual event in the close binary system.

Chen, K.-Y.↗
NASA NTRS1977

Gas stream in Algol

Additional absorption features in the red wings of the Mg II resonance lines near 2800 A are found in observations of Algol made from the Copernicus satellite. The absorption features were clearly seen only during a part of the primary eclipse, in the phase interval 0.90-0.03. The observations are interpreted as being produced by a stream of matter flowing from Algol B in the direction of Algol A. The measured Doppler shifts of the features give the value of 150 km/s as the characteristic velocity of matter in the stream. The mass transfer connected with the stream is estimated to be of the order of 10 to the -13th power solar mass per year.

Cugier, H.↗
NASA NTRS1977

Study of a light curve of Beta Persei at 3428 A

Photometric light-curve data obtained during Copernicus satellite observations of Beta Persei in the Balmer continuum at 3428 A are analyzed and reduced. A small but significant fluctuation with a period of very nearly 0.069167 day in the photometric counts is tentatively attributed to a small perturbation in spacecraft attitude introduced each time the satellite passes from daylight into darkness. The light curve is intensity-rectified, phase-rectified, and solved on the assumption that the limb darkening follows the linear cosine law. The resulting distributions of luminosity among the three components of Beta Persei are plotted, and it is shown that the effective temperature of Algol B may be higher than 5000 K.

Chen, K.-Y.↗
NASA NTRS1976

Variations in the ultraviolet Mg II lines of beta Persei

Copernicus satellite observations have been used to study changes in the Mg II lines in the neighborhood of 2800 A in Algol during eclipse. The resonance lines near 2800 A show doubling near the bottom of primary eclipse. A possible explanation is that emission from component B fills the line centers; the absolute magnitude thus derived for component B agrees with other values in the literature.

Chen, K.-Y.↗
NASA NTRS1975

A spectrometric study of the Lyman-alpha line of beta Persei

A brief description is given to the L-alpha line based on observations made by the Copernicus satellite. No emission was detected. No significant differences were found between observations outside eclipse and those during primary minimum. Some of the blended lines in this spectral region are identified.

Chen, K.-Y.↗
NASA NTRS1975

The eclipsing binary CW Eridani

Results of three-color photoelectric observations of CW Eridani are presented which were made with a 30-inch telescope over the three-year period from 1970 to 1973. The times of minima are computed, solutions of the light curves are obtained, and theoretical light curves are computed from the solutions. The period is determined to be 2.72837 days, and the orbital and photoelectric elements are derived from solutions based on the idealized Russell model.

Chen, K.-Y.↗
NASA NTRS1973

A study of the reflection effect in close spectroscopic binary stars

Four W Ursae Majoris-type binaries were investigated using the simple model of blackbody solid spheres. Numerical computations were carried out for the rotationally broadened profiles of spectral lines Sr II (4077.7) and Ca I (4226.7) and the mean radial velocities. These mean velocities at different phases outside eclipses were compared with sinusoidal values of the radial velocity curve for point masses. Within the present accuracy of observations, the reflection effect is small and may be neglected in the analysis of radial velocity curves.

Chen, K.-Y.↗
NASA NTRS1968

Photoelectric photometry of HD 116994.

HD 116994 period, discussing harmonic analyses made of light and color curves, visual magnitude estimation, pulsation theory results and observation result tables

Chen, K.-Y.↗