PMO OpenIR研究单元&专题: 历算和天文参考系研究团组
http://libir.pmo.ac.cn:80/handle/332002/63
Fri, 21 Sep 2018 06:52:41 GMT2018-09-21T06:52:41ZGravitational time advancement under gravity's rainbow
http://libir.pmo.ac.cn:80/handle/332002/17542
题名: Gravitational time advancement under gravity's rainbow
作者: Deng, Xue-Mei; Xie, Yi
摘要: Under gravity's rainbow, we investigate its effects on the gravitational time advancement, which is a natural consequence of measuring proper time span for a photon's round trip. This time advancement can be complementary to the time delay for testing the gravity's rainbow, because they are sensitive to different modified dispersion relations (MDRs). Its observability on ranging a spacecraft far from the Earth by two radio and a laser links is estimated at superior conjunction (SC) and inferior conjunction (IC). We find that (1) the IC is more favorable than the SC for measurement on the advancement caused by the rainbow; (2) aspecific type of MDR has a significantly larger effect on the advancement than others in both SC and IC cases; and (3) acombination of available optical clocks and the realization of planetary laser ranging in the future will benefit distinguishing the gravity's rainbow from GR by measuring the gravitational time advancement. (C) 2017 The Author(s). Published by Elsevier B.V.Mon, 27 Nov 2017 02:56:40 GMThttp://libir.pmo.ac.cn:80/handle/332002/175422017-11-27T02:56:40ZImproved Solar System bounds on the cosmologically viable f (G) gravity
http://libir.pmo.ac.cn:80/handle/332002/17415
题名: Improved Solar System bounds on the cosmologically viable f (G) gravity
作者: Deng, Xue-Mei; Xie, Yi
摘要: By making use of the supplementary advances of the perihelia provided by INPOP10a and INPOP15a (France) and EPM2011 (Russia) ephemerides, we obtain improved Solar System bounds on the cosmologically viable f (G) gravity, where f is an arbitrary function of the Gauss-Bonnet invariant G. When we estimate new bounds on its model parameters, we consider the Lense-Thirring effect caused by the Sun's angular momentum and the uncertainty of the Sun's quadrupole moment, neither of which were included in related works before. The bounds we obtain in the present work are tighter than the previous ones by at least 5 orders of magnitude.Tue, 21 Nov 2017 07:42:36 GMThttp://libir.pmo.ac.cn:80/handle/332002/174152017-11-21T07:42:36ZSolar System and stellar tests of noncommutative spectral geometry
http://libir.pmo.ac.cn:80/handle/332002/17414
题名: Solar System and stellar tests of noncommutative spectral geometry
作者: Deng, Xue-Mei
摘要: By using purely geometric forces on a noncommutative spacetime, noncommutative spectral geometry (NCSG) was proposed as a possible way to unify gravitation with the other known fundamental forces. The correction of the NCSG solution to Einstein's general relativity (GR) in the four-dimensional spacetime can be characterized by a parameter beta similar to 1/root f(0), where f(0) denotes the coupling constants at the unification. The parameter beta contributes a Yukawa-type correction exp(-beta r)/r to the Newtonian gravitational potential at the leading order, which can be interpreted as either the massive component of the gravitational field or the typical range of interactions carried by that component of the field. As an extension of previous works, we mainly focus on the Solar System and stellar tests of the theory, and the constraints on similar to obtained by the present work is independent of the previous ones. In the Solar System, we investigate the effects of the NCSG on the perihelion shift of a planet, deflection of light, time delay at superior conjunction (SC) and inferior conjunction (IC), and the Cassini experiment by modeling new observational results and adopting new datasets. In the binary pulsars system, based on the observational data sets of four systems of binary pulsars, PSR B1913+ 16, PSR B1534+ 12, PSR J0737-3039, and PSR B2127+ 11C, the secular periastron precessions are used to constrain this theory. These effects in the scale of the Solar System and binary pulsars were not considered in previous works. We find that the lower bounds given by these experiments are beta similar or equal to 10(-9) similar to 10(-10) m(-1), considerably smaller than those obtained in laboratory experiments. This confirms that experiments and observations at smaller scales are more favorable for testing the NCSG theory.Tue, 21 Nov 2017 07:42:34 GMThttp://libir.pmo.ac.cn:80/handle/332002/174142017-11-21T07:42:34ZThe second post-Newtonian light propagation and its astrometric measurement in the Solar System: Light time and frequency shift
http://libir.pmo.ac.cn:80/handle/332002/16251
题名: The second post-Newtonian light propagation and its astrometric measurement in the Solar System: Light time and frequency shift
作者: Deng, Xue-Mei
摘要: The light time equation and frequency shift are worked out in the framework of a second parametrized post-Newtonian (2PPN) formalism in the Solar System barycentric reference system (SSBRS) developed in a recently published paper. Effects of each body's oblateness, spin and translational motion are taken into account for the light propagation. It is found that, at the second post-Newtonian (2PN) approximation, the light time and frequency shift depend on the parameter eta only.Tue, 27 Sep 2016 08:12:22 GMThttp://libir.pmo.ac.cn:80/handle/332002/162512016-09-27T08:12:22ZNew upper limits of a braneworld model with recent Solar System tests
http://libir.pmo.ac.cn:80/handle/332002/16150
题名: New upper limits of a braneworld model with recent Solar System tests
作者: Deng, Xue-Mei; Xie, Yi
摘要: As an extension of previous works on classical tests of a braneworld model which is called as the Dadhich, Maartens, Papadopoulos and Rezania (DMPR) solution, and as an attempt to find more stringent constraints on this model, we investigate its effects on physical experiments and astronomical observations conducted in the Solar System by modeling new observable effects and adopting new datasets. First, we investigate gravitational time delay at inferior conjunction (IC) caused by the braneworld model, which was not considered in previous works, because these measurements are not affected by the solar corona noise. Second, the Cassini superior conjunction (SC) experiment is, for the first time, used to test the DMPR model. Third, compared to previous works, we refine the model, which confronts the perihelion shift induced by the braneworld model with modern Solar System ephemerides INPOP10a (IMCCE, France) and EPM2011 (IAA RAS, Russia). The correction of DMPR solution to Einstein's general relativity (GR) in the four-dimensional spacetime can be characterized by a constant bulk "tidal charge" parameter Q, which is confined in the present work. We find that time delay experiment at IC is independent of Q and not suitable for testing the braneworld model. However, the Cassini SC experiment and modern Solar System ephemerides can give better upper bounds on Q: (1) vertical bar Q vertical bar <= 1.2 x 10(7) m(2) by Cassini, and (2) vertical bar Q vertical bar <= 61 m(2) based on the supplementary advances of the perihelia provided by INPOP10a and vertical bar Q vertical bar <= 3.0 x 10(2) m(2) based on the ones of EPM2011. The latter upper bounds are improved to be tighter than the ones of previous works by at least two orders of magnitude. Besides, the stronger constraints on the brane tension are given by the modern ephemerides, which are lambda >= 3.1 x 10(5) MeV4 for INPOP10a and lambda >= 6.2 x 10(4) MeV4 for EPM2011. These improved upper bounds mean that the Solar System tests can serve as a good testbed for high dimensional theories.Tue, 27 Sep 2016 07:48:07 GMThttp://libir.pmo.ac.cn:80/handle/332002/161502016-09-27T07:48:07ZSolar System tests of a scalar-tensor gravity with a general potential: Insensitivity of light deflection and Cassini tracking
http://libir.pmo.ac.cn:80/handle/332002/16129
题名: Solar System tests of a scalar-tensor gravity with a general potential: Insensitivity of light deflection and Cassini tracking
作者: Deng, Xue-Mei; Xie, Yi
摘要: In the work of Hohmann et al. [Phys. Rev. D 88, 084054 (2013)], the authors worked out the parametrized post-Newtonian (PPN) parameters gamma and beta of a scalar-tensor theory with an arbitrary coupling function and a generic potential, and they found that these two PPN parameters depend on the radial distance r from the Sun, gamma(r) and beta(r). Based on the assumption that measurements on the PPN parameters can be characterized by the shortest distance to the Sun, the authors obtained their best constraints on the model parameters of the scalar-tenor theory by light deflection observation and the Cassini tracking experiment. However, as the authors stated, this approach might not be rigorous. In the present work, we physically model astronomical observations and physical experiments by calculating the null and timelike geodesics in the scalar-tensor theory. We show that, contrary to the results in the previous work, the light deflection and the Cassini tracking cannot distinguish the scalar-tensor theory from general relativity. We also investigate the additional advances in perihelia caused by the largest correction of the scalar field on the Newtonian potential. Since this correction has a Yukawa-like form, we obtain very much improved lower bounds on the model parameters by using current upper limits on the Yukawa parameters.Tue, 27 Sep 2016 07:36:13 GMThttp://libir.pmo.ac.cn:80/handle/332002/161292016-09-27T07:36:13ZThree-dimensional orbit and physical parameters of HD 6840
http://libir.pmo.ac.cn:80/handle/332002/16123
题名: Three-dimensional orbit and physical parameters of HD 6840
作者: Wang, Xiao-Li; Ren, Shu-Lin; Fu, Yan-Ning
摘要: HD 6840 is a double-lined visual binary with an orbital period of similar to 7.5 years. By fitting the speckle interferometric measurements made by the 6 m BTA telescope and 3.5 m WIYN telescope, Balega et al. gave a preliminary astrometric orbital solution of the system in 2006. Recently, Griffin derived a precise spectroscopic orbital solution from radial velocities observed with OPH and Cambridge Coravel. However, due to the low precision of the determined orbital inclination, the derived component masses are not satisfying. By adding the newly collected astrometric data in the Fourth Catalog of Interferometric Measurements of Binary Stars, we give a three-dimensional orbit solution with high precision and derive the preliminary physical parameters of HD 6840 via a simultaneous fit including both astrometric and radial velocity measurements.Tue, 27 Sep 2016 07:35:06 GMThttp://libir.pmo.ac.cn:80/handle/332002/161232016-09-27T07:35:06ZA first-order dynamical model of hierarchical triple stars and its application
http://libir.pmo.ac.cn:80/handle/332002/16076
题名: A first-order dynamical model of hierarchical triple stars and its application
作者: Xu, Xing-Bo; Xia, Fang; Fu, Yan-Ning
摘要: For most hierarchical triple stars, the classical double two-body model of zeroth-order cannot describe the motions of the components under the current observational accuracy. In this paper, Marchal's first-order analytical solution is implemented and a more efficient simplified version is applied to real triple stars. The results show that, for most triple stars, the proposed first-order model is preferable to the zeroth-order model both in fitting observational data and in predicting component positions.Tue, 27 Sep 2016 06:55:21 GMThttp://libir.pmo.ac.cn:80/handle/332002/160762016-09-27T06:55:21ZImproved upper bounds on Kaluza-Klein gravity with current Solar System experiments and observations
http://libir.pmo.ac.cn:80/handle/332002/16073
题名: Improved upper bounds on Kaluza-Klein gravity with current Solar System experiments and observations
作者: Deng, Xue-Mei; Xie, Yi
摘要: As an extension of previous works on classical tests of Kaluza-Klein (KK) gravity and as an attempt to find more stringent constraints on this theory, its effects on physical experiments and astronomical observations conducted in the Solar System are studied. We investigate the gravitational time delay at inferior conjunction caused by KK gravity, and use new Solar System ephemerides and the observation of Cassini to strengthen constraints on KK gravity by up to two orders of magnitude. These improved upper bounds mean that the fifth-dimensional space in the soliton case is a very flat extra dimension in the Solar System, even in the vicinity of the Sun.Tue, 27 Sep 2016 06:55:20 GMThttp://libir.pmo.ac.cn:80/handle/332002/160732016-09-27T06:55:20Z望远镜几何扭曲实测方法仿真研究
http://libir.pmo.ac.cn:80/handle/332002/15201
题名: 望远镜几何扭曲实测方法仿真研究
作者: 李凡； 任树林；Thu, 25 Feb 2016 07:24:43 GMThttp://libir.pmo.ac.cn:80/handle/332002/152012016-02-25T07:24:43Z