منابع مشابه
On the period history of χ Cygni
We discuss the light variability of the Mira variable χ Cygni, present a homogeneous set of times of minimum and maximum light since its discovery date in 1686, and analyse the variations of the pulsation period. There is a substantial cycleto-cycle variation in the pulsations (standard error ∼ 6. d5) with quite strong evidence for a linearly increasing period. Quasicyclic patterns in the O−C d...
متن کاملThe Optical Spectroscopic Evolution of V1974 Cygni (nova Cygni 1992)
Received ; accepted – 2 – ABSTRACT Optical observations of nova V1974 Cygni (Cygni 1992), spanning a 4 year period, have been used to study its spectroscopic evolution. The data cover a wavelength range from ∼ 3200 − 8000Å and follows the nebular evolutionary phase of the ejecta. We have modeled the integrated fluxes by means of the photoionization code CLOUDY. The models were run at a fixed ab...
متن کاملImplementing χ
Calculi are used to reason about functional languages from a theoretical perspective. They allows us to make bold statements about programs based on sound and correct deductive methods. Methods of visualization allow us to gain a better understanding of the communication and interaction involved between processes. Often, graphs are used because of the level of intuition they can bring to a syst...
متن کاملToward a Unified Light Curve Model for Multi-wavelength Observations of V1974 Cygni (nova Cygni 1992)
We present a unified model for optical, ultraviolet (UV), and X-ray light curves of V1974 Cygni (Nova Cygni 1992). Based on an optically thick wind model of nova outbursts, we have calculated light curves and searched for the best fit model that is consistent with optical, UV, and X-ray observations. Our best fit model is a white dwarf (WD) of mass 1.05 M⊙ with a chemical composition of X = 0.4...
متن کاملCygni : a study of its eclipse timings
EM Cygni is a Z Cam-subtype eclipsing dwarf nova. Its orbital period variations were reported in the past but the results were in conflict to each other while other studies allowed the possibility of no period variation. In this study we report accurate new times of minima of this eclipsing binary and update its O−C diagram. We also estimate the mass transfer rate in EM Cygni system and conclud...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1894
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.18941350704