scholarly journals A new determination of lunar orbital parameters, precession constant and tidal acceleration from LLR measurements

2002 ◽  
Vol 387 (2) ◽  
pp. 700-709 ◽  
Author(s):  
J. Chapront ◽  
M. Chapront-Touzé ◽  
G. Francou
Keyword(s):  
Orbital Parameters ◽  
Tidal Acceleration ◽  
Precession Constant

scholarly journals Erratum: Determination of the orbital parameters of binary pulsars

2009 ◽  
Vol 395 (3) ◽  
pp. 1775-1775 ◽  
Author(s):  
P. C. Freire ◽  
M. Kramer ◽  
A. G. Lyne
Keyword(s):  
Orbital Parameters ◽  
Binary Pulsars

scholarly journals Orbits of Galactic Globular Clusters from Schmidt Plate Astrometry

1994 ◽  
Vol 161 ◽  
pp. 453-459 ◽  
Author(s):  
M. Odenkirchen ◽  
R.-D. Scholz ◽  
M.J. Irwin
Keyword(s):  
Globular Clusters ◽  
Proper Motions ◽  
Mass Model ◽  
Orbital Parameters ◽  
The Galaxy ◽  
Galactic Globular Clusters

We present results from orbit integrations for the globular clusters M 3 and M 92. Absolute proper motions recently measured from Tautenburg Schmidt plates and a three-component mass model for the Galaxy have been used to derive the galactic orbits of these clusters. Orbital parameters and the influence of observational uncertainties on the determination of the orbits are discussed.

scholarly journals Dynamical Constants and Reference Parameters for Mars

1980 ◽  
Vol 56 ◽  
pp. 325-328
Author(s):  
William H. Michael ◽  
George M. Kelly
Keyword(s):  
Seasonal Variation ◽  
Rotation Rate ◽  
Direct Determination ◽  
Time Span ◽  
Tracking Data ◽  
Doppler Tracking ◽  
Reference Parameters ◽  
Fundamental Reference ◽  
Precession Constant

AbstractDynamical constants and other fundamental reference parameters for Mars have been derived from analyses of Viking lander ranging and Doppler tracking data covering a time span of nearly four years. Precise values have been obtained for the coordinates of the spin axis and for the rotation rate, suggesting that these Viking-derived values are definitive and are suitable for adoption by the IAU. Preliminary results have been obtained for a small seasonal variation in the rotation rate, and progress has been made toward a direct determination of the precession constant.

scholarly journals Determination of Resonance terms using Optical Observations of Two Meteosat Satellites

1997 ◽  
Vol 165 ◽  
pp. 355-360
Author(s):  
U. Hugentobler ◽  
T. Schildknecht ◽  
G. Beutler
Keyword(s):  
Radiation Pressure ◽  
Ccd Camera ◽  
Least Square ◽  
Optical Observations ◽  
Laser Ranging ◽  
Time Interval ◽  
Orbital Parameters ◽  
Adjustment Procedure ◽  
Relative Errors

AbstractDuring an observation campaign in winter 94/95 astrometric positions from Meteosat 4 and 5 were acquired at the Zimmerwald observatory using a CCD camera mounted in the prime focus of the 0.5 m Satellite Laser Ranging telescope. The measurements cover a time interval of four months, their precision is of the order of .The modeling of radiation pressure for the small, cylindrically shaped satellites is relatively easy and they are therefore excellent objects to probe the geopotential. The orbital parameters and the radiation pressure coefficients for the two satellites as well as the resonant coefficients C22, S22 of the geopotential were determined by a single least square adjustment procedure including all the Zimmerwald observations. The relative errors estimated for the terms C22 and S22 are of the order of 1 ÷ 3 · 10−4.

scholarly journals Note on the Determination of the Neaely Diurnal Free Nutation (Core Nutation) and the Principal Term of Nutation Based on the Astrometric Data

1991 ◽  
Vol 127 ◽  
pp. 385-391
Author(s):  
Ya.S. Yatskiv ◽  
L.D. Kovbasyuk
Keyword(s):  
Accurate Determination ◽  
Principal Term ◽  
Direct Observations ◽  
Vlbi Observations ◽  
Core Boundary ◽  
Insufficient Time ◽  
Astrometric Data ◽  
Free Nutation ◽  
Precession Constant

Due to the highly accurate determination of the corrections to the nutation terms (the IAU-1980 nutation theory) by VLBI observations, the proposal for adoption of the new nutation theory or standard model of nutation is being discussed. At this point there are two unsolved problems:(a)VLBI observations can’t provide reliable estimates of the principal nutation term. The reason is that the correlation between this term and the precession constant is high due to the insufficient time span of these observations (about 10 years).(b)period of free core nutation (FCN) which depends on the ellipticity of the mantle-core boundary has not been, so far, reliably determined from direct observations.In the present paper, we would like to draw attention to the results of the analysis of astrometric latitude and time observations which could be useful for resolving these problems.

The orbits of Ariel 4 and Prospero

1975 ◽  
Vol 343 (1633) ◽  
pp. 257-264 ◽  
Keyword(s):  
Gravitational Field ◽  
Orbital Parameters ◽  
Zonal Harmonics ◽  
Earth’S Gravitational Field ◽  
Tesseral Harmonics ◽  
Visual Observations

Orbital parameters for Ariel 4 and Prospero have been determined at the Royal Aircraft Establishment and made available for use with the respective telemetry analysis programs. Ariel 4 orbit determinations were based on N.A.S.A. Minitrack observations, and Prospero orbit determinations on U.S. Navy observations and a small number of visual observations. Both orbits are near polar (inclination 83° for Ariel 4 and 82° for Prospero) but not otherwise similar. The initial perigee and apogee heights were, respectively, 500 and 600 km for Ariel 4, as against 550 and 1600 km for Prospero. Hence Ariel 4 has experienced much more drag than Prospero and orbital parameters had to be determined at much closer intervals for the former than for the latter, 3 days as against 7 days. The Ariel 4 orbit is being analysed to study the effects of 15th-order tesseral harmonics in the Earth’s gravitational field, and the Prospero orbit has been used in a recent determination of odd zonal harmonics.

scholarly journals The determination of the orbital parameters of WZ Sagittae

1978 ◽  
Vol 184 (4) ◽  
pp. 835-841 ◽  
Author(s):  
A. C. Fabian ◽  
D. N. C. Lin ◽  
J. Papaloizou ◽  
J. E. Pringle ◽  
J. A. J. Whelan
Keyword(s):  
Orbital Parameters

scholarly journals Updated astrometry and masses of the LUH 16 brown dwarf binary

2018 ◽  
Vol 618 ◽  
pp. A111 ◽  
Author(s):  
P. F. Lazorenko ◽  
J. Sahlmann
Keyword(s):  
High Precision ◽  
Photographic Plate ◽  
Brown Dwarf ◽  
Precision Data ◽  
Orbital Parameters ◽  
Very Large Telescope ◽  
High Precision Data ◽  
The Absolute ◽  
The Individual

The nearest known binary brown dwarf WISE J104915.57–531906.1AB (LUH 16) is a well-studied benchmark for our understanding of substellar objects. Previously published astrometry of LUH 16 obtained with FORS2 on the Very Large Telescope was affected by errors that limited its use in combination with other datasets, thereby hampering the determination of its accurate orbital parameters and masses. We improve upon the calibration and analysis of the FORS2 astrometry with the help of Gaia DR2 to generate a high-precision dataset that can be combined with present and future LUH 16 astrometry. We demonstrate its use by combining it with available measurements from the Hubble Space Telescope (HST) and Gemini/GeMS and deriving updated orbital and mass parameters. Using Gaia DR2 as astrometric reference field, we derived the absolute proper motion and updated the absolute parallax of the binary to 501.557 ± 0.082 mas. We refined the individual dynamical masses of LUH 16 to 33.5 ± 0.3 M Jup (component A) and 28.6 ± 0.3 M Jup (component B), which corresponds to a relative precision of ∼1% and is three to four times more precise than previous estimates. We found that these masses show a weak dependence on one datapoint extracted from a photographic plate from 1984. The exact determination of a residual mass bias, if any, will be possible when more high-precision data can be incorporated in the analysis.

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