3,006 research outputs found
Tidal Love numbers of neutron stars
For a variety of fully relativistic polytropic neutron star models we
calculate the star's tidal Love number k2. Most realistic equations of state
for neutron stars can be approximated as a polytrope with an effective index
n~0.5-1.0. The equilibrium stellar model is obtained by numerical integration
of the Tolman-Oppenheimer-Volkhov equations. We calculate the linear l=2 static
perturbations to the Schwarzschild spacetime following the method of Thorne and
Campolattaro. Combining the perturbed Einstein equations into a single second
order differential equation for the perturbation to the metric coefficient
g_tt, and matching the exterior solution to the asymptotic expansion of the
metric in the star's local asymptotic rest frame gives the Love number. Our
results agree well with the Newtonian results in the weak field limit. The
fully relativistic values differ from the Newtonian values by up to ~24%. The
Love number is potentially measurable in gravitational wave signals from
inspiralling binary neutron stars.Comment: corrected Eqs. (20) and (23) and entries in Table (1
Alien Registration- Brooker, James A. (Millinocket, Penobscot County)
https://digitalmaine.com/alien_docs/7701/thumbnail.jp
Some factors associated with absenteeism in a printing factory: a study at the Cape Times, Parow
A MARKETING-SYSTEM APPROACH TO REMOVING DISTRIBUTION BARRIERS CONFRONTING SMALL-VOLUME FRUIT AND VEGETABLE GROWERS
Marketing,
Technology improvement pathways to cost-effective vehicle electrification: Preprint
Electrifying transportation can reduce or eliminate dependence on foreign fuels, emission of green house gases, and emission of pollutants. One challenge is finding a pathway for vehicles that gains wide market acceptance to achieve a meaningful benefit. This paper evaluates several approaches aimed at making plug-in electric vehicles (EV) and plug-in hybrid electric vehicles (PHEVs) cost-effective including opportunity charging, replacing the battery over the vehicle life, improving battery life, reducing battery cost, and providing electric power directly to the vehicle during a portion of its travel. Many combinations of PHEV electric range and battery power are included. For each case, the model accounts for battery cycle life and the national distribution of driving distances to size the battery optimally. Using the current estimates of battery life and cost, only the dynamically plugged-in pathway was cost-effective to the consumer. Significant improvements in battery life and battery cost also made PHEVs more cost-effective than today’s hybrid electric vehicles (HEVs) and conventional internal combustion engine vehicles (CVs)
Relativistic theory of tidal Love numbers
In Newtonian gravitational theory, a tidal Love number relates the mass
multipole moment created by tidal forces on a spherical body to the applied
tidal field. The Love number is dimensionless, and it encodes information about
the body's internal structure. We present a relativistic theory of Love
numbers, which applies to compact bodies with strong internal gravities; the
theory extends and completes a recent work by Flanagan and Hinderer, which
revealed that the tidal Love number of a neutron star can be measured by
Earth-based gravitational-wave detectors. We consider a spherical body deformed
by an external tidal field, and provide precise and meaningful definitions for
electric-type and magnetic-type Love numbers; and these are computed for
polytropic equations of state. The theory applies to black holes as well, and
we find that the relativistic Love numbers of a nonrotating black hole are all
zero.Comment: 25 pages, 8 figures, many tables; final version to be published in
Physical Review
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