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Adams, T. F.

Publications and source records attributed to Adams, T. F..

Light curves for bump Cepheids computed with a dynamically zoned pulsation code

The dynamically zoned pulsation code developed by Castor, Davis, and Davison was used to recalculate the Goddard model and to calculate three other Cepheid models with the same period (9.8 days). This family of models shows how the bumps and other features of the light and velocity curves change as the mass is varied at constant period. The use of a code that is capable of producing reliable light curves demonstrates that the light and velocity curves for 9.8 day Cepheid models with standard homogeneous compositions do not show bumps like those that are observed unless the mass is significantly lower than the 'evolutionary mass.' The light and velocity curves for the Goddard model presented here are similar to those computed independently by Fischel, Sparks, and Karp. They should be useful as standards for future investigators.

Adams, T. F.↗

High-resolution observations of the Lyman alpha sky background

The first high-resolution observations of the Lyman alpha sky background, obtained with a spectrometer on the Copernicus satellite, are examined. The high-resolution observations presented allow the first direct measurement of the heliocentric velocity of the local interstellar medium. The high resolution of the spectrometer and the projection of the earth's orbital velocity along the line of sight made it possible to separate the weak extraterrestrial background feature from the intense geocoronal emission line. The observations also contain considerable information about the Lyman alpha emission from the geocorona. The data permit limits to be placed on the temperature of the gas that produces the background feature.

Adams, T. F.↗