69

+57O30:5 57 17.0 57 50.4 57 58.6 57 54.0 57 46.2 55 46.8 56 34.5

Astron. Nachr., Bd. 301, H. 2 (1980)

13.0 I 3.0 12.5

13.5

I 3.0 I 3.0

12.0

11.0

New Red Variable Stars in two Fields in Cepheus and Cygnus

+51~01:2 50 08.2 51 43.4 50 25.5 49 30.3

(Rlitteilungen der Universitats-Sternwarte zu Jena Nr. 143)

10.0

12.5 11.0 11.0 12.0

w. PFAU and c. FRIEDEMANN

With I Figure (Received 1979, September 12)

The detection of 15 probably long period variables is announced. The observed range of light changes in the Y system are given.

Die Entdeckung von 15 vermutlich lang periodischen roten Veranderlichen aird mitgeteilt. Der hcobachtrte Rereich des Lichtwechsels im r-Bereich wird gegeben.

In a former paper FRIEDEMANN et al. (1977) examined a set of photographic plates in order to detect thc s.upposed light variability of red stars selected by DORSCHNER et al. (1973) on prints of the Palomar Observatory Sky Survey (POSS). Recently the same plates were inspected by means of a stereo comparator for other variables within the fields.

The plates are in the r system and were obtained a t the 60/go-cm Schmidt telescope of Jena University Ob- servatory. The fields are centred at aIg50 = 2 1 ~ 2 4 ~ , d1950= +57"15' (Field I) and aIg50 = 2 1 ~ 5 1 ~ , dIg50= +50°50' (Field 11), the field diameter amounts to 4%. Thirteen and eleven plates, respectively, were obtained between Oct. 1973 and Aug. 1976. For further details concerning the observational material and reduction procedure see FRIEDE- MANS et al. (1977).

During the course of the search a total of 15 new variables has been found. In Table I the relevant data are collected. The number in the first column is the running number of variables detected a t Jena University Obser- vatory. The missing numbers 17 to 21 correspond to the red variables labeled A to E in an earlier paper (FRIEDE- MANN et al. (1977)). Two of these stars (JV 17 and JV IS) were studied on an extensive plate material by BOHME

Table I. List o f new variable stars

No. 8x950

JV 4 JV 5 JV 6 J V 7 JV 8 J V 9 JV 10 JV 11

JV 12 JV 13 JV 14 Jk' 15

JV 23

J V 16 JV 22

2 1 h r o ~ 2 5 ~ 1 1 07

16 06 24 59 28 02 28 33 39 I5

12 01

211134m07s 36 05 40 05 41 32 53 00

54 38 58 54

14.5 14.5 14.0 '4.5 15.0 14.5 15.0 14.0

13.0 14.5 14.0 14.5 14.5 14.5 14.5

Table 2. Observed range of l ight changes of known variables in the r system

Star 1 Am,[mag] I Star 1 Am,[mag]

3.0 1.7: 3.7 3.6 4.6: 4.5 1.8 1.6

3.6 2.1 3.4 2.8 3.7 5.5: 4.5:

70 w. PFAU. C. FRIEDEMANN : New Red Variable Stars in Cepheus and Cygnus

Fig. I . Finding charts for thc objects in Table I . They are reproduccd from the POSS red prints. Xorth is a t the top and east at left. The numbers indicated are the JV numbrrs. The scale is indicated by a bar corresponding to 5' in chart 10. For identification the following

BD stars can be used: 4.5: +57'2295 (ccntrc); 6: 57'2303 (top); 7 : +57'2312 (left); 8 : +57'2322 (centre lower right); 9: +57'234z (upper left); 10: t55'2597 (lower left); 1 1 : f56'2614 (top); 1 2 : i 50'3382 (lower left); 1 3 : +49'3562 (right); 14: t51O3125 (upper left); 15: +50'3411 (centre right)

1 6 : f49'3667 (top); 22: I 5 0 ~ 3 4 9 6 (below centre); 23: +52"3083 (upper left).

(1978, 1979). The colour indices ( B - V ) given in Table I have been determined from the diameters of the stars on the POSS prints using the method introduced by DORSCHNER et al. (1966). The scarcity of observational data pre- vents us from statements as to the character of light variability. The large amplitudes observed and colour indices, however, suggest long period stars like Rliras. That Table I contains only such objects is due to their high detection probability.

In the search a number of already known variables were found. Because for these objects the observed range of light variability Am, in the r system may be of interest the corresponding amounts are collected in Table 2. According to the General Catalogue of Variable Stars, Moscow 1969, all the objects are of Mira type.

For the uncertainty of the photographic scale our r magnitudes may be influended by errors up to f 0.5 mag. We are indebted to Mr. D. UHLIC who detected the variables. Furthermore, we are grateful to Mr. E. SEELICER

for photometry and part of data reduction and to Dr. W. WENZEL, Sonneberg Observatory, for checking the data files of known variable stars.

References ROHME, n. : 197.4, Mitt. uber \'crantlerliche Sterile 8, 74. RBHME, D. : 1979, private communication. DoRscHsER, J., GURTLER, J., SCHIELCKE, R., and SCHMIDT, K.-H.: 1966, Astron. Nachr. 289, 51. FRmnE%iAxs, C . . GURTLER, J., and PFAU, W.: 1977. Astron. Nachr. 298, 327.

Address of the authors:

W. PFAU, C. FRIEDEMAS'N Universitats-Sternwarte Jena Schillergallchen 2 DDR-6900 Jena tierman Democratic Rcpublic