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Newburn, R. L., Jr.

Publications and source records attributed to Newburn, R. L., Jr..

35 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

The International Halley Watch

The International Halley Watch (IHW) is a program designed to promote cooperation, standardization, and archival documentation in all phases of study of Comet Halley during its 1985-86 apparition. Discipline Specialists have been selected to create cooperative nets of ground-based observers encompassing seven different technical areas and to coordinate the observations and publication of results in each. The IHW will promote cooperation among ground-based and space studies of Comet Halley wherever reasonable and feasible. More specifically, the IHW will make ephemerides from the astrometric net available to any country flying a deep space mission. It will coordinate special Halley Watch Days with the arrival dates of space probes or periods of observation from earth orbit. And the IHW will provide a permanent archive in published form of all scientific observations of Comet Halley.

Rahe, J.↗
NASA NTRS1980

Interference filter photometry of periodic comet Ashbrook-Jackson

P/Ashbrook-Jackson has a period of 7.43 years and comes to perihelion at 2.284 AU. It is a low inclination object (12.5 deg) of moderate eccentricity (0.400). In 1963, it made the best possible apparition, coming to perihelion and opposition virtually simultaneously, but no one made physical observations of faint periodic comets in 1963. In 1978 Ashbrook-Jackson came to opposition on Sept. 28, just 40 days after perihelion. It will be just over 100 years before an equally favorable apparition recurs. P/Ashbrook-Jackson was recovered by Pereyra at Cordoba Observatory on April 28, 1977, more than a year and a quarter before perilhelion and already showing a diffuse coma with central condensation. Its helio-centric distance was then 3.7 AU. An extensive program was planned, but equipment problems and weather ultimately limited it to the two nights of data reported here.

Newburn, R. L., Jr.↗
NASA NTRS1979

Optical spectrophotometry of comet Tempel 2 far from the sun

With the advent of mission planning for spacecraft encounters with comets in the 1980s, the lack of basic data on cometary nuclei has become quite apparent and a real problem. More effort is needed on all comets, with special attention given to probable space flight targets such as Tempel 2. The paper presents medium-spectral-resolution spectrophotometry of P/Tempel 2, made at heliocentric distances of 2.66 and 3.02 AU on two dates in 1978. It is shown that optical spectrophotometry of comet Tempel 2 near 3 AU heliocentric distance places strict limits on its activity, the modeled CN production rate having an upper limit of 6 times 10 to the 21st molecules per sec. The observations of P/Tempel 2 are compatible with a bare nucleus of 1.6 km radius (geometric albedo = 0.15) and somewhat redder than the sun.

Spinrad, H.↗
NASA NTRS1979

Models of P/Tempel 2

Quantitative models of Comet Tempel 2 at various heliocentric distances were created using a semi-empirical theory which ties gas production rates to the light curve. Physical properties of the nucleus and gas and dust densities are supplied for a nominal case and two extreme cases at each distance, the extreme cases being based upon a sum-of-negative-tolerances approach.

Newburn, R. L., Jr.↗
NASA NTRS1978

Postperihelion interference filter photometry of the 'annual' Comet P/Encke

Interference filter photometry was taken of Comet Encke on June 14, 1974 (1.07 AU heliocentric distance, postperihelion) at the CTIO (Cerro Tololo Interamerican Observatory) 150-cm reflector. Production rates were calculated as 4.1 x 10 to the 23nd power mol/sec for CN, 5.3 x 10 to 23nd power mol/sec for C3, and 4.3 x 10 to the 24th power mol/sec for C2. These are about three times smaller than at comparable heliocentric distance preperihelion, assuming a value of 100 for the ratio H2O/(C2 + C3 + CN). An upper limit was placed on the production of nonvolatiles at about one-third that of volatiles in mass by assuming a bulk density of 1 g/cu cm, a particle geometric albedo of 0.1, and a phase function of 0.2.

Newburn, R. L., Jr.↗
NASA NTRS1978

The exploration of comets

The structure and origin of comets are reviewed with reference to future cometary research involving fly by and rendezvous missions. Ion-driven spacecraft, to be launched from a Shuttle in the mid-1980s, will theoretically be able to make close observations of Halley's Comet, and fly on to either Tempel 2 or Borelly's Comet during the course of the same mission. A rendezvous, whereby the spacecraft follows a comet in its path around the sun, is considered preferable to a fly by, which will allow only a few hours of observation. Suggested equipment for comet research include IR sensors, X- and Gamma-ray spectrometers, and possibly SEM to analyze the composition of cometary dust particles.

Neugebauer, M.↗
NASA NTRS1976

Scientific possibilities of a solar electric powered rendezvous with comet Encke

The minimum scientific spacecraft instrumentation is considered that is likely to result in as complete an understanding of the composition, structure, and activity of a cometary nucleus as is possible without landing on it. The payload will also give useful results on secondary goals of a better understanding of physical processes in the inner and outer coma. Studies of composition, by means of an actual landing on the surface, details of the internal structure of the nucleus, and sample return were considered beyond the scope of this mission.

Newburn, R. L., Jr.↗
NASA NTRS1975

Planets and satellites of the outer solar system, asteroids, and comets

The cosmogenic significance of outer solar system objects is evaluated with emphasis on planets and larger satellites of greatest biological interest; comets, asteroids, and the smaller satellites are also discussed. Principal physical and rudimentary photometric data for the five outer planets are presented in tables. Sufficient information on planetary motions is included for most calculations in physical planetology.

Newburn, R. L., Jr.↗
NASA NTRS1973

A model of the physical properties of comet Encke

The available observational data on periodic comet Encke were collected and interpreted in order to construct a model of the comet. The model is intended for use in the design of scientific experiments and spacecraft systems to be used on future missions to Encke. Numerical values and ranges of uncertainty are given for all of the important structural, compositional, and photometric parameters with references to the original research from which these were calculated or estimated.

Taylor, F. W.↗
NASA NTRS1970

Why go to the outer planets

Scientific motivation for outer planets exploration covering solar system clues, atmosphere comparisons with earth, radiation and planetary radii measurement, etc

Eisenman, A. R.↗