COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                      Number 2823

                                        Konkoly Observatory
                                        Budapest
                                        26 November 1985

                                        HU ISSN 0374 - 0676


   A SEQUENCE OF COMPARISON STARS IN THE NEIGHBOURHOOD OF TT ARIETIS


  In linking to the photoelectric UBV sequence in SA 71 given by Purgathofer
(1969) and to the UBV magnitudes of Fuhrmann's star c (1981) given by Shafter
(1985) on the plates of the Schmidt camera 50/70/120 cm and with the 
photoelectric 60 cm telescope I of Sonneberg Observatory a sequence of comparison
stars in UBV in the neighbourhood of TT Arietis was established.
  The individual stars which were measured are marked in Figure 1. The
objects of the brighter part of the sequence are identical with known
comparison stars given in the finding charts of the AAVSO (capital letters)
and Fuhrmann (1981) (small letters from a to f). The designation of those
stars has been retained. My own designation of stars is beginning with the
letter g.
  Photoelectric UBV measurements of the comparison stars given by Fuhrmann
(1981) were obtained by W. Wenzel by linking them to Shafter's star 
(V=10.99m, B-V= 0.69m, U-B= 0.23m ).

  The measurements on the photographic plates are extended to fainter stars


                                 [FIGURE 1]



and to those given in the AAVSO finding chart. The individual magnitudes and
colour indices of the comparison stars are listed in Table I. Comparing there

                                 
                                 Table  I

Comparison   V           B          U          B-V       U-B     Remarks
star
a            9.73m       10.26m     10.23m     0.53m     -0.03m  pe
b            10.50       11.13      11.33      0.63      +0.20   pe
c            10.99       11.68      11.91      0.69      +0.23   pe
d            11.02       12.17      13.38      1.15      +1.21   pe
e            11.76       12.34      12.42      0.58      +0.08   pe
f            12.01       13.01      13.80      1.00      +0.79   pe
g            13.80       14.67      15.20      0.87      +0.53   pg
h            14.15       14.94      15.30      0.79      +0.36   pg
i            13.95       14.63      15.05      0.68      +0.42   pg
k            14.55       15.26      15.90      0.71      +0.64   pg
l            15.10       15.74      16.05      0.64      +0.31   pg
m            15.75       15.88      16.05      0.13      +0.17   pg
n            15.75       16.24      16.30      0.49      +0.06   pg
o            15.95       16.12      16.40      0.17      +0.28   pg
p            16.20       16.42      16.25      0.22      -0.17   pg
q            15.75       16.27      16.50      0.52      +0.23   pg
A             9.20        9.55       9.25      0.35      -0.30   pg
K            12.55       13.24      13.65      0.69      +0.41   pg
L            13.25       13.54      13.85      0.29      +0.31   pg
M            13.86       14.37      15.20      0.51      +0.83   pg
N            14.85       15.27      15.60      0.42      +0.33   pg

the magnitude in B with those given by Fuhrmann, it can be seen that the
stars a, b and c are brighter than published previously.





                         W. GOTZ
                       Akademie der Wissenschaften
                       der DDR, Zentralinstitut fur
                       Astrophysik, Sternwarte Sonneberg
                       DDR




References:
Fuhrmann, B., 1981, Mitt. Veranderl. Sterne Sonneberg, 9, 14. [BIBCODE 1981MitVS...9...14F ]
Purgathofer, A.Th., 1969, Lowell Obs. Bull., Vol. VII, 98. [BIBCODE 1969LowOB...7...98P ]
Shafter, A.W., 1985, Astrophys. J., 290, 707. [BIBCODE 1985ApJ...290..707S ]