view Abstract Citations (2) References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The orbital motion of the minor planet (1362) Griqua and the mass of Jupiter. Rabe, Eugene Abstract The minor planet (1362) Griqua is of special interest not only because of its mean daily motion n which is continuously increasing from 596" in 1933 to 607" in 1977, going through the rigorous 2 : I commensurability with respect to Jupiter's mean motion n' during the year 1943, but also because of the large eccentricity e of its orbit, which makes it possible to observe the enormously large perturbations by Jupiter in perihelion oppositions at such close geocentric distances as 1.3 a.u. When the orbital elements of the planet were derived from accurate positions in 6 oppositions during 1935-1956 (Rabe 1956), the final values of the accurate special perturbations computed on NORC as well as of the elements were obtained only by a process of successive approximations, because of the size of the perturbations by Jupiter and their dependence on the basic elements. In Table I the two significant elements n and e TABLE I. n AND e WITH INTERVALS OF 800 DAYS JD a e JD a 27400.5 596.10 0.33975 36200.5 602.98 0.35256 28200 596.19 .34051 37000 602.84 .35314 29000 596.18 .34108 37800 603.17 .35383 29800 596.87 .34189 38600 603.92 .35454 30600 596.71 .34237 39400 603.65 .35544 31400 598.93 .34525 40200 606.00 .35766 32200 599.79 .34667 41000 606.37 .35856 33000 599.43 .34712 41800 606.28 .35907 33800 600.00 .34811 42600 606.93 .35994 34600 600.80 .34838 43400.5 607.22 0.36020 35400.5 601.41 0.35049 have been listed with intervals of 800 days, beginning at JD 2427400.5 = 1933 Nov. 24.0 UT, and ending at JD 2443400.5 = 1977 Sep. 14.0 UT. These osculating values of n and e include the perturbations by all the major planets from Venus to Neptune, but Jupiter is almost exclusively responsible for the remarkable orbital changes exhibited in Table I. From earlier long range computations for a fictitious case of such a critical Hecuba planet (Wilkens 1930) we know already that the longitude perturbations by Jupiter are of zero order and are not limited to any maximum amplitude. The purpose of this note is to point out that in the case of Griqua such rapidly increasing perturbations can be observed under most favorable conditions, and that apparently Griqua is a most suitable asteroid for the determination of Jupiter's mass. The size of the total perturbational displacements Aa cos 6 and A6, observable in the next three perihelion oppositions 1959, 1965 and 1971, has been computed for two dates 20 days a art in each of these most favorable oppositions. These values are listed in Table II, together with TABLE II. PERTURBATIONAL DISPLACEMENT OF GRIQUA IN COMING PERIHELION OPPOSITIONS Date UT p r A cos I Al As I 5 Sep. 29.0 1.270 2.118 24?89 6?12 25?63 Oct. 19.0 1.267 2.109 24.34 4.60 24.77 1965 Oct. 27.0 1.293 2.123 40.73 12.83 42.70 Nov. 16.0 1.300 2.148 38.26 10.51 39.68 1971N0V.25.0 1.384 2.259 57.33 20.70 60.96 Dec. 15.0 1.406 2.313 51.97 18.18 55.o6 the total displacement As, the geocentric distance p, and the heliocentric distance r. The zero epoch of these perturbations is 1935 July 31.903, corresponding to the first observation known for this planet. In 1971, or 35 years later, the observable effect of Jupiter's mass amounts to 610. Observers are urged to observe Griqua as extensively as possible, not only in these perihelion oppositions but in regular oppositions as well. Extended ephemerides will be published in the MPC. The author intends to utilize all suitable observations later on for a determination of the mass of Jupiter. REFERENCES Rabe, E. 1956, Minor Planet Circ. 1459. Wilkens, A. 1930, A. N. 240, 201. University of Cincinnati, Cincinnati, Ohio Publication: The Astronomical Journal Pub Date: March 1959 DOI: 10.1086/107866 Bibcode: 1959AJ.....64...53R full text sources ADS |