8,089 research outputs found
The Photometric Investigation of V921 Her using the Lunar-based Ultraviolet Telescope of Chang'e-3 mission
The light curve of V921 Her in ultraviolet band observed by the Lunar-based
Ultraviolet Telescope (LUT) is analyzed by the Wilson-Devinney code. Our
solutions conclude that V921 Her is an early type marginal contact binary
system with an additional close-in component. The binary system is under poor
thermal contact with a temperature difference of nearly between the two
components. The close-in component contributes about of the total
luminosity in the triple system. Combining the radial velocity study together
with our photometric solutions, the mass of the primary star and secondary one
are calculated to be , . The evolutionary scenario of V921 Her is discussed.
All times of light minimum of V921 Her available in the bibliography are taken
into account and the curve is analyzed for the first time. The most
probable fitting results are discussed in the paper, which also confirm the
existence of a third component ( year) around the binary system. The
period of V921 Her is also undergoing a continuously rapid increase at a rate
of , which may due to mass
transfer from the less massive component to the more massive one
Dynamical generation of dark solitons in spin-orbit-coupled Bose-Einstein condensates
We numerically investigate the ground state, the Raman-driving dynamics and
the nonlinear excitations of a realized spin-orbit-coupled Bose-Einstein
condensate in a one-dimensional harmonic trap. Depending on the Raman coupling
and the interatomic interactions, three ground-state phases are identified:
stripe, plane wave and zero-momentum phases. A narrow parameter regime with
coexistence of stripe and zero-momentum or plane wave phases in real space is
found. Several sweep progresses across different phases by driving the Raman
coupling linearly in time is simulated and the non-equilibrium dynamics of the
system in these sweeps are studied. We find kinds of nonlinear excitations,
with the particular dark solitons excited in the sweep from the stripe phase to
the plane wave or zero-momentum phase within the trap. Moreover, the number and
the stability of the dark solitons can be controlled in the driving, which
provide a direct and easy way to generate dark solitons and study their
dynamics and interaction properties.Comment: 10 pages, 9 figur
- β¦