A5089769108- Astro and Planetary Science
- Planetary Science and Exploration
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Spacecraft Dynamics and Control
- Relativity and Gravitational Theory
- Pulsars and Gravitational Waves Research
- Digital Games and Media
- Cinema and Media Studies
- Scientific Research and Discoveries
- Space Science and Extraterrestrial Life
- Geophysics and Sensor Technology
- Black Holes and Theoretical Physics
- Marine and environmental studies
- Astronomy and Astrophysical Research
- Space Exploration and Technology
- Astronomical Observations and Instrumentation
- Geology and Paleoclimatology Research
- Gamma-ray bursts and supernovae
- Aerospace Engineering and Control Systems
United States Naval Observatory
2014-2024
Charles University
2022-2023
Planetary Science Institute
2022-2023
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2022-2023
United States Navy
2005-2019
United States Department of the Navy
2005-2019
University of Helsinki
2009
University of Minnesota
2002-2003
Harvard University
1999-2001
Tufts University
1996
Any model of tides is based on a specific hypothesis how lagging depends the tidal-flexure frequency. For example, Gerstenkorn (1955), MacDonald (1964), and Kaula (1964) assumed constancy geometric lag angle, while Singer (1968) Mignard (1979, 1980) asserted time lag. Thus, each these two models was certain law scaling The actual dependence frequency more complicated determined by rheology planet. Besides, particular functional form this will unambiguously fix appropriate tidal quality...
While the seismic quality factor and phase lag are defined solely by bulk properties of mantle, their tidal counterparts determined both self-gravitation a body as whole. For qualitative estimate, we model with homogeneous sphere express through in sample material. Although simplistic, our is sufficient to understand that lags not identical. The difference emerges because pulls bulge down. At low frequencies, this reduces strain makes damping less efficient larger bodies. high competition...
We re-examine the popular belief that a telluric planet or satellite on an eccentric orbit can, outside spin–orbit resonance, be captured in quasi-static tidal equilibrium called pseudosynchronous rotation. The existence of such configurations was deduced from oversimplified models assuming either constant torque linear frequency. A more accurate treatment requires decomposed into Darwin–Kaula series over modes, and this decomposition combined with realistic choice rheological properties...
We study the tidal history of an icy moon, basing our approach on a dissipation model, which combines viscoelasticity with anelasticity and takes into account microphysics attenuation. apply this to Iapetus, most remote large moon in Saturnian system. Different authors provide very different estimates for Iapetus's despinning timescale, by several orders magnitude. One reason these differences is choice model used computing spin evolution. As laboratory data viscoelastic properties planetary...
Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning, and also participate the subtle process entrapment bodies into spin-orbit resonances. This makes directly relevant to studies habitability planets their moons. Our work begins with an explanation how friction lagging should be built theory bodily tides. Although much this material can found various publications, short but self-consistent summary on topic has been lacking...
This is a pilot paper serving as launching pad for study of orbital and spin evolution binary asteroids. The rate tidal asteroidal binaries defined by the dynamical Love numbers kl divided quality factors Q. Common in literature (oftentimes illegitimate) approximation with their static counterparts. Since are, approximately, proportional to inverse rigidity, this renders popular fallacy that determined product rigidity factor: . In reality, depend on frequency all rheological parameters...
In Efroimsky & Makarov (2014), we derived from the first principles a formula for tidal heating rate in tidally perturbed homogeneous sphere. We compared it with formulae used literature, and pointed out differences. Using this result, now present three case studies - Mercury, Kepler-10b, triaxial Io. A very sharp frequency-dependence of k2/Q near spin-orbit resonances yields similarly dependence on spin rate. This indicates that physical libration may play major role synchronously rotating...
We use a damped mass-spring model within an N-body code to simulate the tidal evolution of spin and orbit self-gravitating viscoelastic spherical body moving around point-mass perturber. The represents Kelvin–Voigt solid. measure quality function (the dynamical Love number k2 divided by factor Q) from numerically computed drift semimajor axis binary. shape k2/Q, as principal frequency, reproduces kink predicted Efroimsky for response near-spherical homogeneous rotators. demonstrate that we...
GJ 581d is a potentially habitable super-Earth in the multiple system of exoplanets orbiting nearby M dwarf. We investigate this planet's long-term dynamics with an emphasis on its probable final rotation states acquired via tidal interaction host. The published radial velocities for star are re-analyzed benchmark planet detection algorithm to confirm that there no evidence recently proposed two additional planets (f and g). Limiting scope four originally detected planets, we assess...
Parameterised by the Love number $k_2$ and tidal quality factor $Q$, inferred from lunar laser ranging (LLR), dissipation in Moon follows an unexpected frequency dependence often interpreted as evidence for a highly dissipative, melt-bearing layer encompassing core-mantle boundary. Within this, more or less standard interpretation, basal layer's viscosity is required to be of order $10^{15}$ $10^{16}$ Pa s, its outer radius predicted extend zone deep moonquakes. While reconciliation those...
A formula for the tidal dissipation rate in a spherical body is derived from first principles to correct some mathematical inaccuracies found literature. The development combined with Darwin–Kaula formalism tides. Our intermediate results are compared those by Zschau and Platzman. When restricted special case of an incompressible planet spinning synchronously without libration, our final can be commonly used expression Peale & Cassen. However, two turn out differ, as contributions all...
Motivated by a recent study Lazarian and Draine, which showed that high degree of grain alignment the paramagnetic dust is achievable if rates internal relaxation are controlled Barnett process, we undertake an alternative mechanism dissipation, namely, inelastic dissipation energy in oblate grains. We find deformations at double frequency were disregarded earlier studies dominate relaxation. Our results indicate for sufficiently grains, e.g. grains with 4:1 axis ratio, or/and formed...
We have designed and constructed a ``dispersed Fourier Transform Spectrometer'' (dFTS), consisting of conventional FTS followed by grating spectrometer. By combining these two devices, we negate substantial fraction the sensitivity disadvantage for high resolution, broadband, optical spectroscopy, while preserving many advantages inherent to interferometric spectrometers. In addition, implemented simple inexpensive laser metrology system, which enables very precise calibration interferometer...
Abstract Observational evidence of white dwarf planetary systems is dominated by the remains exo-asteroids through accreted metals, debris discs, and orbiting planetesimals. However, exo-planets in these play crucial roles as perturbing agents, can themselves be perturbed close to Roche radius. Here, we illustrate a procedure for computing tidal interaction between near-spherical solid planet. This method determines planet’s inward and/or outward drift, whether planet will reach radius...
It is conceivable that a few thousand confirmed exoplanets initially harboured satellites similar to the moons of Solar system or larger. Could some them have survived over aeons dynamical evolution present day? The conditions are harsh for exomoons in such systems because greater influence host star and tidal torque it exerts on planet. We investigate stability niches around hundreds innermost which needed parameters known today, determine these moons' long-term survival. General lower...
In most books the Delaunay and Lagrange equations for orbital elements are derived by Hamilton–Jacobi method: one begins with two-body Hamilton in spherical coordinates, performs a canonical transformation to elements, obtains system. A standard trick is then used generalize approach N-body case. We reexamine this step demonstrate that it contains an implicit condition which restricts dynamics 9(N−1)-dimensional submanifold of 12(N−1)-dimensional space spanned their time derivatives. The...
The goal of this paper is to demonstrate how the internal symmetry N-body celestial-mechanics problem can be exploited in orbit calculation. We start with summarising research reported (Efroimsky [CITE], [CITE]; Newman & Efroimsky Goldreich [CITE]) and develop its application planetary equations non-inertial frames. This class problems treated by variation-of-constants method. As explained previous publications, whenever a standard system six (in Lagrange, Delaunay, or other form) employed...