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(received 1996 Mar. 15) ZZ Dra. Improved elements.
Summary:
The mira variable ZZ Dra has been observed by members of ASTRONOMISK SELSKAB, Denmark. From observations covering the years 1947-1994 I have derived 25 maxima, and these have been compared to the elements given in GCVS 4 (Max=41209, P=267,9), see the table below.
As the residuals are rather great I made a trend line analysis, which gave as result the following elements:
Max= 41222 P=269.42
as the best expression of the stars variation in the nearly 50 years.
The residuals when compared to my new elements are also given in the table.
Maxima:
GCVS4 new
JD Magn. E O-C O-C
max 32312 -33 -56 -19
max 32587 -32 -49 -14
max 32861 -31 -43 -9
max 33418 -29 -22 9
max 33687 -28 -21 9
max 33965 -27 -11 17
max 34227 -26 -17 10
max 34509 -25 -3 23
max 37999 -12 5 10
max 39047 -8 -19 -20
max 43908 8,9 10 20 -8
max 44165 9,0 11 9 -21
max 44718 9,8 13 26 -6
max 44976 10,4 14 16 -18
max 45265 8,8 15 38 2
max 45799 9,6 17 36 -3
max 46075 9,2 18 44 3
max 46332 8,7 19 33 -9
max 46886 9,8 21 51 6
max 47427 9,1 23 56 8
max 47700 9,1 24 61 12
max 47961 8,5 25 55 4
max 48231 8,4 26 57 4
max 48504 9,4 27 62 8
max 49581 9,0 31 67 7
Ole Klinting
e-mail: ole.klinting@53611928.da.diatel.dk
(vsnet 577)
I was interested to see Ole Klinting's analysis of the long-term periodicity of ZZ Dra. This is excellent work. I might mention that I prepared a photometric sequence in the field at the request of the AAVSO. It is published on IBVS 4055 (29 July 1994). If desired, I can e-mail the text (but not the accompanying chart) to any one who wishes it. You can recover an electronic version from the IBVS homepage, which linked from the vsnet Web page.
\Brian Skiff (bas@lowell.edu)