Análise Dimensional (Notas de Aula Livro 2) (Portuguese Edition)
The audio of these data reflected distinct patterns within the evolutions of supercycles and superhumps that matched pervious observations and proved to be effective aids in data analysis.
Observations and light curve solutions of a selection of shallow-contact W UMa binaries. The light curve solutions revealed that these binaries have overcontact configurations with small fillout factors within 0. Seven of them undergo total eclipses and their photometric mass ratios should be accepted with confidence.
The results from the modeling and analysis of our observations reveal that: i All targets undergo total eclipses and their photometric mass ratios should be accepted with confidence; ii All stellar components are late-type dwarfs; iii The temperature difference of target components does not exceed K; iv All targets have overcontact configurations with fill-out factor around 0. Masses, radii and luminosities of the stellar components were estimated by the empirical relation "period, orbital axis" for short- and ultrashort-period binaries.
Buckets of ash track tephra flux from Halema' uma 'u Crater, Hawai'i. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema' uma 'u Crater.
This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations. The setting of the vent—easily accessible from the Hawaiian Volcano Observatory HVO —is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.
The observations occurred during a super-high state never before observed in HU Aqr. The near-infrared observations show a corresponding flux increase of times over previous J and K observations.
Números em texto integral
However, the near-infrared eclipse minimum during this super-high state are the same as seen in previous observations, indicating that the eclipse in the near-infrared is total. We present a detailed comparison of the EUV and near-infrared emission of HU Aqr as a function of orbital phase and discuss the geometry and physical properties of the high energy and infrared emitting regions.
We present EUV phase-resolved photometry and spectroscopy and show that the He emission line is not produced on the heated face of the secondary star, but emanates from the inner illuminated regions of the coupling region and accretion stream. We comment on the overall structure of the accretion geometry as well.
- English Correspondences to the German adverb auch.
- Nenhum Problema Tem Solução: Um Arquivo Digital do Livro do Desassossego?
- Quand Se Fanent les Regrets (FICTION) (French Edition).
We explore a range in possible input parameters and model assumptions to delineate under what conditions each model may be preferred. The newly obtained data confirmed the basic findings reported in Kato et al. There was a systematic difference in the period derivatives for the systems with superhump periods longer than 0. We suggest that this difference was possibly caused by a relative lack of frequently outbursting SU UMa -type dwarf novae in this period regime in the present study.
We recorded a strong beat phenomenon during the superoutburst of IY UMa. A close correlation between the beat period and the superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of the superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps.
We also present a formulation for a variety of Bayesian extensions to traditional period analyses. We compare the masses of the NO UMa binary components to those predicted by five sets of stellar evolution models at the age of the Ursa Major group. We find excellent agreement between our measured masses and model predictions with little systematic scatter between the models.
NO UMa joins the short list of nearby, bright, late-type binaries having known ages and fully characterized orbits. A new mechanism of long-term period variations for W UMa -type contact binaries.
W UMa -type contact binaries belong to close binary systems whose components exactly overflow their Roche lobes and share a common convective envelope CCE. In the last twenty years, the long-term variations of their orbital periods have been thought to depend on several mechanisms.
Now, we suggest a new mechanism: CCE-dominated mechanism. The CCE-dominated mechanism is found based on our numerical result, especially at high mass ratios, that the orbital periods P of contact binaries change very much with their fill-out factors f. Because f is taken as a measurement of the thickness of CCE, the physical cause for the variation of P is a mass transfer between CCE and components.
Further, an f-dominated simplification model for this mechanism is introduced. According to it, P may change in a long-term oscillation way with a similar time scale of the thermal modulation, meanwhile q is decreasing slowly till the two components merge. It could be also applied to explain the presence of extremely short period, high mass ratio and deep contact binaries. Therefor, the effect of CCE on the variations of orbital periods may have been underestimated before. Observations and light curve solutions of a selection of middle-contact W UMa binaries. The light curve solutions revealed that the components of each target are of G and K spectral types.
The binaries of the sample have middle-contact configurations whose fillout factors are within the range 0. The only exception is NSVS which is in deeper contact fillout factor of 0. It precisely obeys the relation between mass ratio and fillout factor for deep, low mass ratio overcontact binaries. One of the eclipses of almost all targets except MM Peg is an occultation and their photometric mass ratios and solutions could be accepted with confidence.
We found that the target components have almost equal temperatures but differ considerably in size and mass. The components of the partially-eclipsed MM Peg have close parameters. This subclassification is well-determined for all totally-eclipsed binaries. The targets confirm the trends in which W-subtype systems have smaller periods and lower temperatures than A subtype binaries.
The light curves of Broglia , Contr. It is found that the light curve of the binary star has changed from W-subtype to A-subtype according to Binnendijk's classification.
Guide Análise Dimensional (Notas de Aula Livro 2) (Portuguese Edition)
This variation may be caused by the activity of dark spot on the primary component. Combining four newly determined times of the light minimum with others published in the literature, the orbital period change of the system was investigated. The period oscillation can be explained either by the light-time effect via the presence of an unseen third body or by magnetic-activity cycles of the components. This indicates that it is on the TRO-controlled stage of the evolutionary scheme proposed by Qian. The asymmetry of the light curves requires a large, single star spot on the smaller, less massive secondary component.
The modeled spot varied little during the year range of photometric observations.
Among the 16 shallow-contact systems with a decreasing orbital period, MR Com has the lowest mass ratio e. The shallow-contact configuration, the low-mass ratio, and the long-term period decrease all suggest that systems similar to MR Com are on the AML-controlled stage of the evolutionary scheme proposed by Qian. They will oscillate around a critical mass ratio and evolve into a deep contact with a higher mass ratio. The small-amplitude cyclic change in the O - C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion.
The variations of the orbital period were analyzed based on 12 new determined times of light minimum together with the others compiled from the literature. Photometric solutions determined with the Wilson-Devinney method suggest that BI CVn is a contact binary with a degree of contact of The asymmetry of the light curves was interpreted by the presence of dark spots on both components, and absolute parameters were determined by combining the photometric elements with the spectroscopic solutions given by Lu.
The observed period decrease can be plausibly explained by a combination of the mass transfer from the primary to the secondary and angular momentum loss via magnetic braking. The cyclic period oscillation suggests that BI CVn is a triple system containing a tertiary component with a mass no less than 0. As in the cases of the other contact binaries e. The classical explosive basaltic eruption spectrum is traditionally defined by the following end member eruption styles: Hawaiian and Strombolian.
The field use of high-speed cameras has enabled volcanologists to make improved quantifications and more accurate descriptions of these classical eruptions styles and to quantify previously undecipherable activity including activity on the basaltic eruption spectrum between the two defined end members. Explosive activity in at the free surface of the Halema' uma 'u lava lake at Kilauea exhibited features of both sustained Hawaiian fountaining and transient Strombolian explosivity.
Most of this activity is internally triggered by the internal rise of decoupled gas bubbles from below the lake's surface, but external triggering via rock falls, was also observed. Here I identify three styles of bubble bursting and spattering eruptive activity isolated events, clusters of events, and prolonged episodes at the lava lake, and distinguished them based on their temporal and spatial distributions.
Isolated events are discrete single bubble bursts that persist for a few tenths of seconds to seconds and are separated by repose periods of similar or longer time scales.
Cluster of events are closely spaced, repeated events grouped around a narrow point source, which persist for seconds to minutes. Prolonged episodes are groupings of numerous events closely linked in space and time that persist for tens of minutes to hours. Analysis of individual events from high-speed camera images indicates that they are made up of up to three phases: the bubble ascent phase, the bursting and pyroclast ejection phase, and the drain back and rebound phase.
Based on the numerical parameters established in this study, the activity was relatively weak i. We present a detailed analysis of the interesting W UMa binary FI Boo in view of the spectroscopic signature of a third body through photometry, period variation, and a thorough investigation of solution uniqueness. The results were tested by heuristic scanning and parameter kicking to provide the consistent and reliable set of parameters that was used to obtain the initial masses of the progenitors 1. We also investigated the evolutionary status of massive components with several sets of widely used isochrones.
However, it has been neglected in photometric investigations.