Occultation by a Possible Third Satellite of Neptune

  title={Occultation by a Possible Third Satellite of Neptune},
  author={H. J. Reitsema and William B. Hubbard and Larry Allen Lebofsky and David J. Tholen},
  pages={289 - 291}
The 24 May 1981 close approach of Neptune to an uncataloged star was photoelectrically monitored from two observatories separated by 6 kilometers parallel to the occultation track. An 8.1-second drop in signal, recorded simultaneously at both sites, is interpreted as resulting from the passage of a third satellite of Neptune in front of the star. From the duration of the event, the derived minimum diameter for an object sharing Neptune's motion is 180 kilometers. If the object was in Neptune's… 
Occultation detection of a neptunian ring-like arc
The apparent closest approach of the star SAO186001 to Neptune was observed photoelectrically on 22 July 1984 at Cerro Tololo Inter-American Observatory. A 32% signal drop lasting about 1.2 s was
1981N1: A Neptune Arc?
An object in the vicinity of Neptune detected in 1981 by simultaneous stellar occultation measurements at observatories near Tucson, Arizona, was interpreted as a new Neptune satellite. A
An Explanation for Neptune's Ring Arcs
Analysis of Voyager data shows that a radial distortion with an amplitude of approximately 30 kilometers is traveling through the ring arcs, a perturbation attributable to the nearby satellite Galatea, and the arcs appear to be azimuthally confined by a resonant interaction with the same satellite.
The Voyager 2 Encounter with the Neptunian System
An overview of the Voyager 2 encounter with Neptune is presented, including a brief discussion of the trajectory, the planned observations, and highlights of the results described in the 11 companion
Notes on an initial satellite system of Neptune
The comparison of masses and sizes of the Neptunian satellites and of Pluto and Charon to the secondaries of the planetary, Jovian, Saturnian and Uranian systems support the hypotheses, first, that
Shepherding model for Neptune's arc ring
An incomplete arc ring has recently been discovered around Neptune1. Here, a model to explain the confinement of this ring is developed. The ring may be azimuthally confined near a triangular
Observations of Neptunian rings by Voyager Photopolarmeter Experiment
The Voyager photopolarimeter experiment detected the Neptunian rings 1989N1R and possibly 1989N2R. These rings were also photographed by the Voyager imaging cameras in August 1989. Our firm detection


The rings of Uranus
AT least five rings encircle the planet Uranus—as indicated by five brief occultations of the star SAO 158687 that occurred both before and after its occultation by Uranus on 10 March 1977. We
Predicted occultations by Neptune - 1981-1984
Predictions are presented for eight occultations by and appulses to Neptune from 1981 through 1984. Of special interest are a near-central occultation of Hyd - 22 deg 58794 on June 15, 1983, and a
Reliability of Minor Planet Satellite Observations
Observations of the 1973 Pallas occultation indicate that spurious events may be easily misidentified as true occultations, and that caution must be exercised in interpreting such occurrences.
The need for redundant observations such as those presented here is discussed in H. Reitsema
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We used the pole orientation given in Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac (Her Majesty's Stationery Office
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Change of global climate during recent 100 years" (a copy of the manuscript may be obtained from the author at the Geophysical Institute
Larson with the 154-cm telescope. A wide-field photograph obtained several days later by P. Bowell at Lowell Observatory contained no candidate objects