Sufficient conditions for escape in the three-body problem

Sufficient conditions are given for the escape of a member of a three-body system. The set of conditions are similar to those given previously by Tevzadze (1962). The new set compares favorably in most cases with that of Tevzadze.     

Periodic,consecutive-collision orbits in the restricted problem forμ≠1/2

Sequences of periodic, consecutive-collision orbits in the restricted problem of three bodies have been found for cases where the two primaries are not of equal mass. Each sequence is imbedded in a family of consecutive-collision orbits. There seems to be an infinite number of such families and an infinite number of members in each sequence. Some of the orbits are shown graphically.     

Observations of the horizontal velocity field surrounding sunspots

During the summer and fall of 1971, Doppler spectroheliograms were obtained for several sunspots located near the solar limb. These observations confirm a previous result based on the study of only a few sunspots that in the plage-free photosphere surrounding sunspots the spatially-averaged, horizontal flow tends to be outward at 0.5–1.0 km s^–1 for distances typically 10000–20000 km beyond the outer boundary of the penumbra. It is suggested that these material motions are the means by which small-scale fragments of magnetic flux are carried away from sunspots.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Surface projections of array beam patterns

Described is an application of surface projection calculations of array beam patterns. An example is presented showing how the surface patch illuminated by the transmitted pulse from a monostatic active sonar system intersects the surface projection of the beam pattern as a function of time.     

Lunar bulk sample trace element contents and kreep

The geochemical coherence between the labile element Cl and more refractory F, K, REE and P in lunar soils is utilized to gain insight into the evolution of the lunar samples studied.Paper dedicated to Prof. Harold C. Urey on the occasion of his 80th birthday on 29 April 1973.Work sponsored by USAEC and NASA.     

Analysis of UVSP Dopplergrams and magnetograms and their calibration using the orbital velocity of the SMM spacecraft

To infer velocities and longitudinal magnetic fields from Dopplergram and magnetogram signals obtained by the Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission, one must know the width of the observed emission line. Although the instrument control system provided for a line-width calibration feature which utilized periodically commanded shifts of the line, it was not always used. However, it is possible to use the time-varying line-of-sight component of the orbital velocity of the spacecraft as a means of calibrating the line width for each pixel in a raster. Such a method based on a least-squares fit of the observed Doppler signal to the line-of-sight component of the spacecraft velocity is described here; it then applied to magnetogram observations. As background, the theoretical expressions for the interpretation of the observed Dopplergram and magnetogram signals for both wide and narrow exit slits are also summarized.     

On the physics of a long decay X-ray event

A long decay X-ray event (LDE) which appeared as an expanding loop system on the solar limb on 13–14 August 1973 was well observed temporally (with Skylab ATM S056 and S054 X-ray telescopes) and spectrally (with S082A XUV spectroheliograph). We summarize and supplement the extensive discussion in the literature. In addition, a one-dimensional hydrodynamic study is undertaken to investigate both increasing and decreasing phases of the event. Results indicate that the inferred temperature gradients along the loops during the heating phase are consistent with unrestricted dynamic and conductive flows along magnetic field lines. Furthermore, we conclude that it cannot be unequivocally stated that enhanced emission at the tops of loops is due to pressure gradients along the field lines. Finally, the large emission measure variations in the 10⁵–10⁶ K plasma during the event's decline may be due simply to the temperature dependence of radiative decay within a multi-loop configuration.Presently a NRC Associate at NASA/MSFC, Space Sciences Laboratory, MSFC, Ala. 35812, U.S.A.Presently at NASA/MSFC, Space Sciences Laboratory, MSFC, Ala. 35812, U.S.A.     

Computer model of wind, waves, and longshore currents during a coastal storm

A mathematical model has been developed to forecast or hindcast wind, waves, and longshore currents during the passage of a coastal storm. Storm intensity is a function of the barometric pressure gradient which is modeled by rotating an inverted normal curve around the center of an ellipse. The length and orientation of the major and minor axes of the ellipse control the size and shape of the storm. The path of the storm is determined by a sequence of storm positions for the hindcast mode, and by interpolated positions assuming constant speed and direction for the forecast mode. The site location, shoreline orientation, and nearshore bottom slope provide input data for the shore position. The geostrophic wind speed and direction at the shore site are computed from the latitude and barometric pressure gradient. The geostrophic wind is converted into surface wind speed and direction by applying corrections for frictional effects over land and sea. The surface wind speed and direction, effective fetch, and wind duration are used to compute wave period, breaker height, and breaker angle at the shore site. The longshore current velocity is computed as a function of wave period, breaker height and angle, and nearshore slope. The model was tested by comparing observed data for several coastal locations with predicted values for wind speed, wave period and height, and longshore current velocity. Forecasts were made for actual storms and for hypothetical circular and elliptical storms.