[vsnet-alert 884] Possible fading of Z UMi

[Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>]

    The R CrB-type variable star Z UMi is reported to be fainter than usual
as indicated by the following observations (cf. vsnet-obs 5713 by G. Hanson).

  YYMMDD(UT)   mag  code
  970502.033   116  POY
  970502.131   113  HSG
  970502.974   115  BMM
  970503.010   116  POY
  970503.144   114  HSG
  970505.194   116  HSG
  970506.171   117  HSG
  970507.005   116  POY
  970507.381   121  HSG

    Z UMi was last observed in a deep dust minimum around 1996 January to
April.  This star, however, shows significant light variation even at
maximum.   Moments of temporary fadings (from VSNET potings):

              approx. JD
   1995 Oct.   2449990
        Dec.     50070    (major fading)
   1996 June     50250
        Nov.     50400
   1997 May?     50570?

    There seems to be a characteristic time of ~170 days between these
fadings, which is close to the possible 130 day period reported in Benson
et al. 1994 (AJ 108, 247).

Regards,
Taichi Kato

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