Astronomy and Astrophysics Iii. Observational Guidelines for Mode Identification
نویسنده
چکیده
On the basis of almost 2000 b, y photoelectric observations of θ Tucanae collected in an international campaign at two sites and of almost 1500 v, u observations collected at one site, observational guidelines for mode identification have been searched. Not only the generally used plane (Ab−y/Ay versus φb−y φy) but each combination of the nonadiabatic observables including amplitude ratio vs. amplitude ratio and phase difference vs. phase difference planes were checked for guidelines. Especially Ab/Ay amplitude ratio and φb−y φb phase difference proved to be useful criteria for mode separation in the case of θ Tucanae. The 10 pulsational frequency values published previously by Paparó et al. (1996) are distributed in three groups according to Ab/Ay and in two distinct levels according to φb−y φb. The groups consist of closely spaced frequencies. Group III (15.86, 15.94 and 17.06 cycles/day) displays a higher, distinct level than the others according to the Ab−y/Ay amplitude ratio and unusual behaviour in u colour. Although the discriminative plane does not give the exact value of quantum numbers but predicts which theoretical modes must share the same behaviour. Calibration of the pure observational guidelines by new, delicate theoretical calculation for planes of nonadiabatic observables concerning the location of theoretical modes is urged.
منابع مشابه
Astronomy and Astrophysics the Δ Scuti Star Fg Vir. Iv. Mode Identifications and Pulsation Modelling
This paper examines the mode identification and presents pulsation models for FG Vir, for which 24 frequencies have been detected. Histograms of the frequency spacings show peaks which are identified with adjacent radial orders and rotational splitting. Pulsational l values are deduced for eight modes by comparing the observed photometric phase lags between v and y variations with calculated va...
متن کاملThe Crisis Confronting Standard Big Bang Nucleosynthesis
This manuscript is the written version of the material I attempted to cover at “Critical Dialogues in Cosmology”. My position is that although BBN is inevitable in an expanding universe filled with radiation and baryons, at present there is a conflict between the abundances of the light nuclides predicted by standard, big bang nucleosynthesis (SBBN) and those inferred from current observational...
متن کاملThe Effect of Solar Particles in the Choice of Alloy Shielding in a Satellite
The damages and logical failures in dierent parts of a satellite may occur during a solar event, when a bulk of solar energetic particles approaching the Earth. During solar events, these particles may cause extensive damages which are even permanent (hard errors). A way of damage reduction is designing a proper coating as the fuselage. As protons are the major component of solar particles and ...
متن کاملThe Search for Neutrino Sources beyond the Sun
The hope is that in the near future neutrino astronomy, born with the identification of thermonuclear fusion in the sun and the particle processes controlling the fate of a nearby supernova, will reach throughout and beyond our Galaxy and make measurements relevant to cosmology, astrophysics, cosmic-ray and particle physics. The construction of a high-energy neutrino telescope requires a huge v...
متن کامل