TY - JOUR

T1 - Detection of a coherent oscillation with a 769.63-s period in the intermediate polar EI UMa (PG 0834+488)

AU - Kozhevnikov, V. P.

N1 - This work was supported by the Federal Agency for Science and Innovations (State contract 02.740.11.0247 from July 7, 2009) and the Federal Agency for Education within the framework of the “Scientific and Scientific–Educational Personnel of Innovation Russia” Federal Goal-Oriented Program for 2009–2013.

PY - 2010/8/1

Y1 - 2010/8/1

N2 - Recently, it has been shown that the cataclysmic variable EI UMa should be attributed to intermediate polars on the basis of its X-ray spectrum. However, no short-period oscillations with a high degree of coherence typical of intermediate polars could be detected in this star. Therefore, it was suggested to call it a “hidden” intermediate polar. Using a multichannel photometer and a 70-cm telescope, we performed observations of EI UMa for 60 h. Analysis of the observations has clearly revealed a brightness oscillation with a period of 769.63±0.10 s and a mean semiamplitude of 0.m 008 completely coherent during one month of our observations that was detectable during each of the 13 observing nights. On the basis of this detection, EI UMa should be considered a classical intermediate polar rather than a hidden one. In addition, we have managed to detect the orbital variability of EI UMa for the first time. The orbital light curve is extremely interesting, showing evidence of partial eclipses of the accretion flow.

AB - Recently, it has been shown that the cataclysmic variable EI UMa should be attributed to intermediate polars on the basis of its X-ray spectrum. However, no short-period oscillations with a high degree of coherence typical of intermediate polars could be detected in this star. Therefore, it was suggested to call it a “hidden” intermediate polar. Using a multichannel photometer and a 70-cm telescope, we performed observations of EI UMa for 60 h. Analysis of the observations has clearly revealed a brightness oscillation with a period of 769.63±0.10 s and a mean semiamplitude of 0.m 008 completely coherent during one month of our observations that was detectable during each of the 13 observing nights. On the basis of this detection, EI UMa should be considered a classical intermediate polar rather than a hidden one. In addition, we have managed to detect the orbital variability of EI UMa for the first time. The orbital light curve is extremely interesting, showing evidence of partial eclipses of the accretion flow.

UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=000280702300004

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=77955383446

U2 - 10.1134/S1063773710080049

DO - 10.1134/S1063773710080049

M3 - Article

VL - 36

SP - 554

EP - 568

JO - Astronomy Letters

JF - Astronomy Letters

SN - 1063-7737

IS - 8

ER -