We measured the light-curve of the asteroid （147） Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of （...We measured the light-curve of the asteroid （147） Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of （147） at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for （147）, from a preliminary estimation, is not less than 1.26：1.展开更多
The basic physical parameters of asteroids, such as spin parameters, shape and scattering parameters, can provide us with information on the formation and evolution of both the asteroids themselves and the entire sola...The basic physical parameters of asteroids, such as spin parameters, shape and scattering parameters, can provide us with information on the formation and evolution of both the asteroids themselves and the entire solar system. In a majority of asteroids, the disk-integrated photometry measurement constitutes the primary source of the above knowledge. In the present paper, newly observed photometric data and existing data on（585） Bilkis are analyzed based on a Lommel-Seeliger ellipsoid model. With a Markov chain Monte Carlo（MCMC） method, we have determined the spin parameters（period, pole orientation）and shape（b/a, c/a） of（585） Bilkis and their uncertainties. As a result, we obtained a rotational period of 8.5738209 h with an uncertainty of 9×10^-7h, and derived a pole of（136.46°, 29.0°） in the ecliptic frame of J2000.0 with uncertainties of 0.67°and 1.1°in longitude and latitude respectively. We also derived triaxial ratios b/a and c/a of（585） Bilkis as 0.736 and 0.70 with uncertainties of 0.003 and 0.03 respectively.展开更多
New CCD photometric observations for asteroid（1028）Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rot...New CCD photometric observations for asteroid（1028）Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rotation period of 11.680±0.001 hours is derived with the Phase Dispersion Minimization（PDM） method.In addition,using the Amplitude-Aspect method,the elementary results of the pole orientation of asteroid（1028）Lydina are obtained：λp=111°＋4°-4°,βp=31°＋4°-5°. Meanwhile,the axial ratios of the tri-axial ellipsoid are estimated：a/b=1.77＋0.10 -0.08 and b/c=1.17＋0.07 -0.09 .展开更多
文摘We measured the light-curve of the asteroid （147） Protogeneia in November 2004, with a CCD detector attached to the 1-meter telescope at the Yunnan Observatory, China. The synodic period and maximum amplitude of （147） at this apparition are 7.852 hours and 0.25 mag, respectively. The value of a/b for （147）, from a preliminary estimation, is not less than 1.26：1.
基金funded by the National Natural Science Foundation of China(Grant Nos.11073051 and 11473066)supported,in part,by the Academy of Finland(Project 1257966)
文摘The basic physical parameters of asteroids, such as spin parameters, shape and scattering parameters, can provide us with information on the formation and evolution of both the asteroids themselves and the entire solar system. In a majority of asteroids, the disk-integrated photometry measurement constitutes the primary source of the above knowledge. In the present paper, newly observed photometric data and existing data on（585） Bilkis are analyzed based on a Lommel-Seeliger ellipsoid model. With a Markov chain Monte Carlo（MCMC） method, we have determined the spin parameters（period, pole orientation）and shape（b/a, c/a） of（585） Bilkis and their uncertainties. As a result, we obtained a rotational period of 8.5738209 h with an uncertainty of 9×10^-7h, and derived a pole of（136.46°, 29.0°） in the ecliptic frame of J2000.0 with uncertainties of 0.67°and 1.1°in longitude and latitude respectively. We also derived triaxial ratios b/a and c/a of（585） Bilkis as 0.736 and 0.70 with uncertainties of 0.003 and 0.03 respectively.
基金funded by the National Natural Science Foundation of China(Grant Nos.10933004 and 11073051)
文摘New CCD photometric observations for asteroid（1028）Lydina,carried out with the 1-m and 2.4-m telescopes at Yunnan Observatory from 2011 December 19 to 2012 February 3,are presented.Using the new light curves,the rotation period of 11.680±0.001 hours is derived with the Phase Dispersion Minimization（PDM） method.In addition,using the Amplitude-Aspect method,the elementary results of the pole orientation of asteroid（1028）Lydina are obtained：λp=111°＋4°-4°,βp=31°＋4°-5°. Meanwhile,the axial ratios of the tri-axial ellipsoid are estimated：a/b=1.77＋0.10 -0.08 and b/c=1.17＋0.07 -0.09 .
