The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform
Stephen G Bosi - One of the best experts on this subject based on the ideXlab platform.
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Measures of 62 Southern Pairs
arXiv: Solar and Stellar Astrophysics, 2020Co-Authors: Matthew James, Rod Letchford, Graeme L. White, Meg Emery, Stephen G BosiAbstract:We report lucky imaging observations of 62 pairs at mid-southern declinations sourced from the WDS with separations larger than 4 arc seconds and magnitude less than 10. The measures comprise separations and PA calibrated against Alpha Centauri AB and drift scans, presented as weighted means of these two calibration methods, with formal internal uncertainties \delta\rho = 80 mas and \delta PA = 0.056(deg). We also compare our measures against 1) extrapolated historic measures, 2) GAIA DR2 data and 3) measures determined from HIPPARCOS and GAIA observations. Our best estimate of our bias against these 3 databases are \rho \approx 10 \pm 30 mas and PA \approx 0.04 \pm 0.08(deg). These formal uncertainties are consistent with the internal uncertainties of \delta\rho = 80 mas and \delta PA = 0.056(deg). We also report Rectilinear Elements for 61 pairs, Grade 5 Orbital Elements for 5 pairs and suggest 5 pairs as Optical Doubles (4 of which are new).
Bosi Stephen - One of the best experts on this subject based on the ideXlab platform.
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Measures of 62 Southern Pairs
2020Co-Authors: James Matthew, Letchford Rod, White, Graeme L, Emery Meg, Bosi StephenAbstract:We report lucky imaging observations of 62 pairs at mid-southern declinations sourced from the WDS with separations larger than 4 arc seconds and magnitude less than 10. The measures comprise separations and PA calibrated against Alpha Centauri AB and drift scans, presented as weighted means of these two calibration methods, with formal internal uncertainties \delta\rho = 80 mas and \delta PA = 0.056(deg). We also compare our measures against 1) extrapolated historic measures, 2) GAIA DR2 data and 3) measures determined from HIPPARCOS and GAIA observations. Our best estimate of our bias against these 3 databases are \rho \approx 10 \pm 30 mas and PA \approx 0.04 \pm 0.08(deg). These formal uncertainties are consistent with the internal uncertainties of \delta\rho = 80 mas and \delta PA = 0.056(deg). We also report Rectilinear Elements for 61 pairs, Grade 5 Orbital Elements for 5 pairs and suggest 5 pairs as Optical Doubles (4 of which are new).Comment: 24 pages, 6 Figures (Fig5 consists of 61 Rectilinear Plots and Fig6 consists of 5 orbital plots
Matthew James - One of the best experts on this subject based on the ideXlab platform.
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Measures of 62 Southern Pairs
arXiv: Solar and Stellar Astrophysics, 2020Co-Authors: Matthew James, Rod Letchford, Graeme L. White, Meg Emery, Stephen G BosiAbstract:We report lucky imaging observations of 62 pairs at mid-southern declinations sourced from the WDS with separations larger than 4 arc seconds and magnitude less than 10. The measures comprise separations and PA calibrated against Alpha Centauri AB and drift scans, presented as weighted means of these two calibration methods, with formal internal uncertainties \delta\rho = 80 mas and \delta PA = 0.056(deg). We also compare our measures against 1) extrapolated historic measures, 2) GAIA DR2 data and 3) measures determined from HIPPARCOS and GAIA observations. Our best estimate of our bias against these 3 databases are \rho \approx 10 \pm 30 mas and PA \approx 0.04 \pm 0.08(deg). These formal uncertainties are consistent with the internal uncertainties of \delta\rho = 80 mas and \delta PA = 0.056(deg). We also report Rectilinear Elements for 61 pairs, Grade 5 Orbital Elements for 5 pairs and suggest 5 pairs as Optical Doubles (4 of which are new).
James Matthew - One of the best experts on this subject based on the ideXlab platform.
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Measures of 62 Southern Pairs
2020Co-Authors: James Matthew, Letchford Rod, White, Graeme L, Emery Meg, Bosi StephenAbstract:We report lucky imaging observations of 62 pairs at mid-southern declinations sourced from the WDS with separations larger than 4 arc seconds and magnitude less than 10. The measures comprise separations and PA calibrated against Alpha Centauri AB and drift scans, presented as weighted means of these two calibration methods, with formal internal uncertainties \delta\rho = 80 mas and \delta PA = 0.056(deg). We also compare our measures against 1) extrapolated historic measures, 2) GAIA DR2 data and 3) measures determined from HIPPARCOS and GAIA observations. Our best estimate of our bias against these 3 databases are \rho \approx 10 \pm 30 mas and PA \approx 0.04 \pm 0.08(deg). These formal uncertainties are consistent with the internal uncertainties of \delta\rho = 80 mas and \delta PA = 0.056(deg). We also report Rectilinear Elements for 61 pairs, Grade 5 Orbital Elements for 5 pairs and suggest 5 pairs as Optical Doubles (4 of which are new).Comment: 24 pages, 6 Figures (Fig5 consists of 61 Rectilinear Plots and Fig6 consists of 5 orbital plots
Stephen Case - One of the best experts on this subject based on the ideXlab platform.
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How bright planets became dim stars: planetary speculations in John Herschel's double star astronomy.
Endeavour, 2014Co-Authors: Stephen CaseAbstract:Previous research on the origins of double star astronomy in the early nineteenth century emphasized the role mathematical methods and instrumentation played in motivating early observations of these objects. The work of the British astronomer John Herschel, however, shows that questions regarding the physical nature of double stars were also important. In particular, an analysis of John Herschel's early work on double stars illustrates the way in which speculations regarding these objects were shaped by assumptions of the properties of stars themselves. For Herschel, a major consideration in double star astronomy was distinguishing between types of double stars. Optical Doubles were useful in determining parallax while binary Doubles were not. In practice, classification of a specific double star pair into one of these categories was based on the assumption that stars were of approximately the same luminosity and thus differences in relative brightness between stars were caused by difference in distances. Such assumptions, though ultimately abandoned, would lead Herschel in the 1830s to advance the possibility that the dim companion stars in certain double star pairs were not stars at all but in fact planets.