منابع مشابه
Unusual Phase Reversal of Superhumps in ER Ursae Majoris
We studied the evolution of superhumps in the peculiar SU UMa-type dwarf nova, ER UMa. Contrary to the canonical picture of the SU UMa-type superhump phenomena, the superhumps of ER UMa show an unexpected phase reversal during the very early stage (∼5 d after the superoutburst maximum). We interpret that a sudden switch to so-called late superhumps occurs during the very early stage of a supero...
متن کاملThe dynamical stability of W Ursae Majoris-type systems
Theoretical study indicates that a contact binary system would merge into a rapidly rotating single star due to tidal instability when the spin angular momentum of the system is more than a third of its orbital angular momentum. Assuming that W UMa contact binary systems rigorously comply with the Roche geometry and the dynamical stability limit is at a contact degree of about 70%, we obtain th...
متن کاملA TIGHT UPPER LIMIT ON OSCILLATIONS IN THE AP STAR ǫ URSAE MAJORIS FROM WIRE PHOTOMETRY
Observations of ǫ UMa obtained with the star tracker on the Wide Field Infrared Explorer (WIRE) satellite during a month in mid-2000 are analyzed. This is one of the most precise photometry of an Ap star. The amplitude spectrum is used to set an upper limit of 75 parts per million for the amplitude of stellar pulsations in this star unless it accidentally oscillates with a single mode at the sa...
متن کاملPhotometry and Spectroscopy of KS Ursae Majoris during Superoutburst
We report photometric and spectroscopic observations of the SU UMa-type dwarf novae, KS Ursae Majoris, during its 2003 February superoutburst. Modulations with a period of 0.07017 ± 0.00021 day, which is 3.3% larger than the orbital period, have been found during the superoutburst and may be positive superhumps. A maximum trough-to-peak amplitude of around 0.3 magnitude is determined for this s...
متن کاملAccretion Disc Evolution in DW Ursae Majoris: A Photometric Study
We present an analysis of CCD photometric observations of the eclipsing novalike cataclysmic variable DW UMa obtained in two different luminosity states: high and intermediate. The star presents eclipses with very different depth: ∼ 1.2 mag in the high and ∼ 3.4 mag in the intermediate state. Eclipse mapping reveals that this difference is almost entirely due to the changes in the accretion dis...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1889
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.18891211005