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Evolution of starspot regions in DM UMa

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dc.contributor.author Mohin, S
dc.contributor.author Raveendran, A. V
dc.contributor.author Mekkaden, M. V
dc.contributor.author Hall, D. S
dc.contributor.author Henry, G. W
dc.date.accessioned 2009-02-04T16:38:33Z
dc.date.available 2009-02-04T16:38:33Z
dc.date.issued 1985-10
dc.identifier.citation Astrophysics and Space Science, Vol. 115, No. 2, pp. 353 - 368 en
dc.identifier.issn 0004-640X
dc.identifier.uri http://hdl.handle.net/2248/4333
dc.description.abstract B andV photometry of DM UMa obtained between January, 1980 and June, 1984 is presented. Analysis yields a mean photometric period 7d.478±0d.010, compared to the known oribital period of 7d.492±0d.009. Light curves obtained during any two seasons do not agree in any of the following: shape, amplitude, phases of the light maxima and minima, mean light level, or brightness at the light maxima and minima. From the change inB-V over the photometric period, we concludethat the hemisphere visible during the light minimum is cooler than that seen during light maximum. The mean colorB-V=1m.065±0m.002 is consistent with K1 III or K2 IV. Phases of light minima lie on two well-separated groups with different slopes; the corresponding periods are 7d.471±0d.002 and 7d.481±0d.001, in dicating that both migrate linearly towards decreasing orbital phase. In terms of the starspot model this indicates that two respective centers of activity were situated at different longitudes and latitudes on a differentially rotating star. From circumstantial evidence we infer that the dark region seen from 1979 onwards disintegrated sometime between the 1982 and 1983 observing seasons, leaving behind an area of relatively high surface brightness. We can put a lower limit of about four years on the lifetime of a center of activity. en
dc.language.iso en en
dc.publisher Kluwer Academic Publishers en
dc.relation.uri http://adsabs.harvard.edu/abs/1985Ap%26SS.115..353M en
dc.relation.uri http://dx.doi.org/10.1007/BF00653812 en
dc.subject Astronomical Photometry en
dc.subject Light Curve en
dc.subject Periodic Variations en
dc.subject Starspots en
dc.subject X Ray Sources en
dc.subject Astronomical Models en
dc.subject Binary Stars en
dc.subject Stellar Color en
dc.subject Stellar Magnitude en
dc.title Evolution of starspot regions in DM UMa en
dc.type Article en


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