795 research outputs found
The evolutionary stage of an RRs star SX Phe
The evolutionary stage for a short period variable SX Phe was investigated. It was assumed that SX Phe is a mixed star with low metal abundance in which the material was mixed after the star evolved off the main sequence, and is in the second hydrogen burning stage. The validity of this hypothesis was examined by constructing two evolutionary sequences with (X,Z,M/solar mass) = (0.5,0.004,0.75) and (0.5,0.001,0.70) in the hydrogen burning phase and computed the pulsation period. Agreement between theoretical results and observational data was sufficient to conclude that the mixed model is actually adequate for SX Phe. The applicability of this model to other RRs stars is briefly discussed
The Invisible Monster Has Two Faces: Observations of Є Aurigae with the Herschel Space Observatory
We present Herschel Space Observatory photometric observations of the unique, long-period eclipsing binary star Є Aurigae. Its extended spectral energy distribution is consistent with our previously published cool (550 K) dust disk model. We also present an archival infrared spectral energy distribution of the side of the disk facing the bright F-type star in the binary, which is consistent with a warmer (1150 K) disk model. The lack of strong molecular emission features in the Herschel bands suggests that the disk has a low gas-to-dust ratio. The spectral energy distribution and Herschel images imply that the 250 GHz radio detection reported by Altenhoff et al. is likely contaminated by infrared-bright, extended background emission associated with a nearby nebular region and should be considered an upper limit to the true flux density of Є Aur
Transition Systems over Continuous Time-Space
AbstractThis paper gives a transition system over continuous time-space, which is a system of functions of continuous time-space into descrete states. This system is situated between the cellular automata and the partial differential equations. This paper shows the reasonable sufficient condition of the uniquness of the solution
Bounded Arithmetic in Free Logic
One of the central open questions in bounded arithmetic is whether Buss'
hierarchy of theories of bounded arithmetic collapses or not. In this paper, we
reformulate Buss' theories using free logic and conjecture that such theories
are easier to handle. To show this, we first prove that Buss' theories prove
consistencies of induction-free fragments of our theories whose formulae have
bounded complexity. Next, we prove that although our theories are based on an
apparently weaker logic, we can interpret theories in Buss' hierarchy by our
theories using a simple translation. Finally, we investigate finitistic G\"odel
sentences in our systems in the hope of proving that a theory in a lower level
of Buss' hierarchy cannot prove consistency of induction-free fragments of our
theories whose formulae have higher complexity
First-order Goedel logics
First-order Goedel logics are a family of infinite-valued logics where the
sets of truth values V are closed subsets of [0, 1] containing both 0 and 1.
Different such sets V in general determine different Goedel logics G_V (sets of
those formulas which evaluate to 1 in every interpretation into V). It is shown
that G_V is axiomatizable iff V is finite, V is uncountable with 0 isolated in
V, or every neighborhood of 0 in V is uncountable. Complete axiomatizations for
each of these cases are given. The r.e. prenex, negation-free, and existential
fragments of all first-order Goedel logics are also characterized.Comment: 37 page
The Steady Accretion Discs Irradiated by the Central Neutron Star
The vertical structure of steady accretion discs surrounding a neutron star is investigated with the effect of X-ray irradiation from the central part. Incident X-ray and thermal radiation are treated in two-colour Eddington\u27s approximation. The structure of discs is modified by the X-ray irradiation, but the thickness is not increased remarkably
Geology and Palynology of the Hilly Area Southeast of Ichinoseki City, Iwate Prefecture, Japan
Stratigraphical and palynological studies on the Cenozoic deposits of the hilly area southeast of Ichinoseki City, Iwate Prefecture, were undertaken to determine the biostratigraphy based upon the pollen grains, the geological ages of the stratal units based upon the fossil pollen, the conditions under which the sedimentary basin was developed, and the relationship between transportation and deposition of the pollen. The stratigraphical sequence of the vertically and laterally variable lithofacies was determined, the geological structure of the sedimentary basin analysed, and the relationship between lithofacies and pollen-content interpreted from the viewpoint of aqueous and wind transportation. The paleoclimatic conditions during the ages of the different formation was worked out, and consideration was given to the features of the hinterland during deposition of the respective formations. Concerning the palynological study, the procedure, descriptions and interpretations are given in detail. A total of 9 species of pollen distributed among 34 genera were determined from the Pliocene and Early Pleistocene sediments of the area. Among them 4 species are considered new form-species or species
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