Eclipse mapping of starspots on XY UMa in 1992 and 1995

Andrew Collier Cameron, Ronald William Hilditch

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10 Citations (Scopus)


We present and analyse V-band light curves of the detached eclipsing binary system XY UMa, obtained in 1992 October, 1995 March and November, and 1996 February. The light-curve morphology of this system is known to vary on time-scales of a few days. We have used eclipse mapping techniques to search for evidence that cool starspots are the agents responsible for the variability of the light curve. We derive a new set of geometric system parameters, which we find to be very similar to those derived by Hilditch & Bell. The image derived from the 1992 light curve shows an amorphous band of unresolved spots with a low filling factor, extending over much of the inward-facing hemisphere of the primary. This result is consistent with the extent of the dark-zone model proposed by Hilditch & Bell in their earlier analysis of this same light curve. Irregularities in the primary eclipse profile observed in 1995 and early 1996 are consistent with the eclipse of a dark spot or spots on the inner face of the primary. The major spot in this region appears to be resolved on our 9 degrees surface grid, indicating that the spot consists of an unbroken umbral region some 15 degrees in radius.

Original languageEnglish
Pages (from-to)pp.567-574.
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 21 May 1997


  • stars, activity
  • binaries, eclipsing
  • stars, imaging
  • stars, individual, XY UMa
  • stars, late-type
  • stars, magnetic fields


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