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Dumont, P.

Publications and source records attributed to Dumont, P..

The Visual Orbit of 64 Piscum

We report on the determination of the visual orbit of the double-lined spectroscopic binary system 64 Piscum with data obtained by the Palomar Testbed Interferometer in 1997 and 1998.

stellar astrophysics interferometry

Palomar Testbed Interferometer

The Palomar Testbed Interferometer (PTI) is an infrared, phase-tracking interferometer in operation at Palomar Mountain since July 1995. It was funded by NASA for the purpose of developing techniques and methodologies for doing narrow-angle astrometry for the purpose of detecting extrasolar planets.

optical

The Visual Orbit of Pegasi

Pegasi (HR 8430, HD 210027) is a nearby, short-period (10.2 d) binary system with a F5V primary and a ~ G8V secondary in a circular orbit.

Pegasi HR 8430

406-MHz geostationary SAR experiment

The ability of a 406-MHz satellite to detect and locate aeronautical, maritime, and terrestrial distress incidents is investigated. The geostationary satellite, uplink and downlink budgets, and processors utilized in the experiment are described. The experiment involves: (1) benchmark testing, (2) verification of spacecraft repeater performance, (3) system evaluation, and (4) environmental testing. The Canadian processor data reveal that the processor threshold is 28 dB Hz, the degradation at 27 dB Hz is significant, the median distress message throughput time is 6 minutes, and the microcomputer can handle 10 distress incidents per hour.

Dumont, P.

A compact Dopplergraph/magnetograph suitable for space-based measurements of solar oscillations and magnetic fields

A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-omega power spectra which show clear- the solar nonradial p-mode oscilations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission.

Rhodes, E. J., Jr.

Laser-induced gas breakdown - Spectroscopic and chemical studies.

Discussion of the results of several experimental investigations on laser-induced gas breakdown. The experiments included time-resolved spectroscopy, direct detection of H atoms with a TiO2 probe, and chemical reactions; each of them provided insight into the behavior of the medium at different times. Chemical reactions and explosions have been initiated by the laser beam when a plasma was created. No primary multiphotonic absorption and no macroscopic chemical reactions were observed below the breakdown threshold.

De Montgolfier, PH.