Engineering topics

Depater, I.

Publications and source records attributed to Depater, I..

4 records

NASA NTRS1991

Observations of formaldehyde and search for cyanoacetylene in Comet Brorsen-Metcalf (1989o)

The Very Large Array (VLA) was used in September 1989 to search Comet P/Brorsen-Metcalf (1989o) for the 1 sub 11-1 sub 10 transition of formaldehyde (H2CO) at 4,829.659 MHz and for the J equals 1-0, F equals 2-1 rotational transition of cyanoacetylene (HC3N) at 9098.3321 MHz. A new technique was used in reducing the data. Data blocks which were either 3x3 pixels, 5x5 pixels, or 9x9 pixels were examined for a signal from H2CO. Using this approach, different pixel clusters within the field of view can be sampled to optimize the coupling of the synthesized beam to the gas distribution. HC3N is of immediate interest as a cometary molecule because it may be a reservoir of carbon and a source of cometary CN. Our search for HC3N emission at 3.3 cm wavelength demonstrated that for this molecule the VLA can be expected to reach significant levels of sensitivity in many comets.

Snyder, Lewis E.↗

NASA NTRS1984

A Review of the Millimeter and Centimeter Observations of Uranus

Millimeter and centimeter wave astronomical data of Uranus are presented and discussed. Some recent observations of the brightness distribution across the disk at 2 cm and 6 cm wavelength are reported. Data related to the variability of the microwave spectrum are reanalyzed, taking into account the strong variation of temperature with wavelength, and including up to date data. The results indicate that the brightness temperatures of Uranus have probably reached their maximum values. The evidence for the depletion of ammonia in the upper atmosphere is discussed.

Gulkis, S.↗

NASA NTRS1982

Saturn's rings resolved by the VLA

High resolution radio data of Saturn were obtained at 1.3, 2, 6, and 21 cm, at different inclination angles of the ring plane. Results on optical depth measurements in the rings are described. There is no wavelength dependence in the optical depth of the rings between 1.3 and 6 cm. This indicates that there are not many small particles (sizes of a few centimeters) in the B-ring, which ring is responsible for most of the observed obscuration. This result agrees with the Voyager radio occultation experiment.

Depater, I.↗

NASA NTRS1977

Maps of Jovian radio emission

Observations were made of Jupiter with the Westerbork telescope at all three frequencies available: 610 MHz, 1415 MHz, and 4995 MHz. The raw measurements were corrected for position errors, atmospheric extinction, Faraday rotation, clock, frequency, and baseline errors, and errors due to a shadowing effect. The data was then converted into brightness distribution of the sky by Fourier transformation. Maps of both thermal and nonthermal radiation were developed. Results indicate that the thermal disk of Jupiter measured at a wavelength of 6 cm has a temperature of 236 + or - 15 K. The radiation belts have an overall structure governed by the trapping of electrons in the dipolar field of the planet with significant beaming of the synchrotron radiation into the plane of the magnetic equator.

Depater, I.↗