8 research outputs found
HST and ground-based eclipse observations of V2051 Ophiuchi: Binary parameters
We report on high-speed eclipse photometry of the dwarf nova V2051 Oph while
it was in a low brightness state, at B ~ 16.2 mag. In comparison to the average
IUE spectra, the ultraviolet continuum and emission lines appear reduced by
factors of, respectively, ~4 and ~5. Flickering activity is mostly suppressed
and the lightcurve shows the eclipse of a compact white dwarf at disc centre
which contributes ~60 per cent of the total light at 3900--4300 A. We use
measurements of contact phases in the eclipse lightcurve to derive the binary
geometry and to estimate masses and relevant dimensions. We find a mass ratio
of q= 0.19+/-0.03 and an inclination of i= 83+/-2 degrees. The masses of the
component stars are M_1 = 0.78+/-0.06 M_dot and M_2 = 0.15+/-0.03 M_dot. Our
photometric model predicts K_1 = 83+/-12 km/s and K_2= 435+/-11 km/s. The
predicted value of K_1 is in accordance with the velocity amplitude obtained
from the emission lines after a correction for asymmetric line emission in the
disc is made (Watts et al. 1986). The secondary of V2051 Oph is significantly
more massive than the secondaries of the other ultra-short period dwarf novae.
V2051 Oph is probably a relatively young system, whose secondary star had not
enough time to evolve out of thermal equilibrium.Comment: 16 pages, 7 postscript figures, coded using MNRAS latex style. To
appear in Monthly Notices of the Royal Astronomical Society. Revised version
with changes in section 4.3. For related papers and files see
ftp://fsc01.fsc.ufsc.br/pub/bap and http://www.fsc.ufsc.br/~astr
Universidade Federal de Itajubá
The objective of this paper is to utilize the SIPOC, flowchart and IDEF0 modeling techniques combined to elaborate the conceptual model of a simulation project. It is intended to identify the contribution of these techniques in the elaboration of the computational model. To illustrate such application, a practical case of a high-end technology enterprise is presented. The paper concludes that the proposed approach eases the elaboration of the computational model.