相关论文: Directly testing gravity with Proxima Centauri
Recent studies have shown that velocity differences of very wide binary stars, measured to high precision with GAIA, can provide an interesting test for modified-gravity theories which emulate dark matter; in essence, MOND-like theories…
Astronomical observations reveal a major deficiency in our understanding of physics $-$ the detectable mass is insufficient to explain the observed motions in a huge variety of systems given our current understanding of gravity, Einstein's…
Estimates of the size of the feeding zone of the planet Proxima Centauri c have been made at initial orbital eccentricities of planetesimals equal to 0.02 or 0.15. The research is based on the results of modeling of the evolution of…
High precision spectrographs can enable not only the discovery of exoplanets, but can also provide a fundamental measurement in Galactic dynamics. Over about ten year baselines, the expected change in the line-of-sight velocity due to the…
It is found that Gaia DR3 binary stars selected with stringent requirements on astrometric measurements and radial velocities naturally satisfy Newtonian dynamics without hidden close companions when projected separation $s \lesssim 2$ kau,…
The discovery of Proxima b, a terrestrial temperate planet, presents the opportunity of studying a potentially habitable world in optimal conditions. A key aspect to model its habitability is to understand the radiation environment of the…
The $\alpha$ Cen binary system is a well-known stellar system with very accurate observational constraints to structure of its component stars. In addition to the classical non-seismic constraints, there are also seismic constraints for the…
We review the results from {\it Mariner 10} regarding Mercury's gravity field and the results from radar ranging regarding topography. We discuss the implications of improving these results, including a determination of the polar component,…
At radio wavelengths, solar-type stars emit thermal free-free and gyroresonance, gyrosynchrotron, and impulsive coherent emission. Thermal free-free emission originates at layers where the optical depth is close to unit, while high…
Stellar soft X-ray ([1, 100] Angstrom) and Extreme Ultraviolet (also EUV, [100, 920] Angstrom; jointly, XUV) radiation affects the evolution and chemistry of exoplanet atmospheres. It is however uncertain to what extent the radiation's…
We present the analysis of a kinematic data set of stars in the globular cluster NGC 2419, taken with Keck/DEIMOS. Combined with a reanalysis of deep HST and Subaru imaging data, which provide an accurate luminosity profile of the cluster,…
In the future interstellar exploration at near-relativistic speeds will be possible using beamed energy laser propulsion. With this, spacecraft as small as gm mass picospacecraft become candidates for the exploration of deep space, with a…
The MOND modified gravity paradigm, best known for its agreement with galactic rotation curve data, is difficult to devise laboratory tests for. MOND's predictions differ substantially from Newtonian gravity only in the case of very small…
This work presents the simulation results of the radio science experiment onboard the proposed Heavy Metal mission to the M-type asteroid (216) Kleopatra. Earth-based radiometric measurements (range and range-rate), complemented by images…
We present new analyses of ALMA 12-m and ACA observations at 233 GHz (1.3 mm) of the Proxima Centauri system with sensitivities of 9.5 and 47 $\mu$Jy beam$^{-1}$, respectively, taken from 2017 January 21 through 2017 April 25. These…
The "holy grail" in planet hunting is the detection of an Earth-analog: a planet with similar mass as the Earth and an orbit inside the habitable zone. If we can find such an Earth-analog around one of the stars in the immediate solar…
We lay out and apply methods to use proper motions of individual kinematic tracers for estimating the dynamical mass of star clusters. We first describe a simple projected mass estimator and then develop an approach that evaluates directly…
In astrometric binaries, the presence of a dark, unseen star can be inferred from the gravitational pull it induces on its luminous binary companion. While the orbit of such binaries can be characterized with precise astrometric…
The 3D velocities of M31 and M33 are important for understanding the evolution and cosmological context of the Local Group. Their most massive stars are detected by Gaia, and we use Data Release 2 (DR2) to determine the galaxy proper…
We study the cosmological constraints on the variation of the Newton's constant and on post-Newtonian parameters for simple models of scalar-tensor theory of gravity beyond the extended Jordan-Brans-Dicke theory. We restrict ourselves to an…