COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 1016 Konkoly Observatory Budapest 1975 July 3 THREE REVISED PERIODS AND TWO NEW VARIABLE STARS New observations on Nantucket plates have yielded periods for the five variable stars listed in the Table. Two are relatively minor revisions of periods already included in the GCVS; one is a period related by spurious-period formulae to the previously published value; and the last two are for recent discoveries by students working at the Maria Mitchell Observatory during the summer. Finder charts are given for the three in Cygnus. In each field, as an aid to identification, a BD star is marked with an A. New or Revised Periods --------------------------------------------------------------------------- Star R.A.(1900) Dec. Max Min Type J.D. Period Pg Days --------------------------------------------------------------------------- AB Com 12h13m48s+24d12' 15. [17 M 42188. 194.7 CY Com 12 23 15 +25 30 15. 15.5 RR 42561.570 0.757881 QY Cyg 19 55 14 +37 22.5 14.9 15.8 Cep 42250.685 3.89188 1 19 24 34 +41 20.9 14.0 15. EA 42309.622 3.72315 2 19 56 35 +43 25.3 14.0 14.8: RR 41915.652 0.581147 --------------------------------------------------------------------------- AB Com. The published period of 201.3d does not satisfy all of the observations acquired here, whereas 194.7d does represent all of the Nantucket plates, three from Yale, eight scattered early Harvard plates, as well as the dates of discovery given by Hoffmeister and the epoch of maximum given in the GCVS. Although positive observations on this faint star were available for only 63 individual days, they span an interval of 93 epochs and include 12 observed maxima. CY Com. The published period of 0.43113d proves to be spurious. About 140 observations taken from 1964 through 1974 were equally well satisfied by a slight revision of the published period, by 0.759434d, and 0.7578801d. A long night-run of six plates obtained May 8-9. 1975, however, satisfies only the last. The various periods are inter-related through the common intervals between the observations. Most of the estimates of brightness were carried out by Sharon Beck, a student at Yale University. QY Cyg. Some 600 Nantucket observations from 1920 to 1974 by Bonnie Buratti and D. Hoffleit indicate a moderate revision from the previously published period of 3.89175d. In the Figure the star A is BD +37d3708. [FIGURE 1] Var. 1. Discovered by Lucia Dexter in 1974, who estimated the brightness on 175 plates and obtained an approximate period of 3.72d. The period is now based on 1200 plates from J.D. 21038 to 42314, representing a span of 5715 epochs during which 35 minima were observed. The magnitudes given are only approximate. In the Figure star A is the bright variable TT Lyr, BD +41d3353. Var. 2. Discovered by Bonnie Buratti in 1973, some 900 provisional estimates of brightness were carried out by Lucia Dexter in 1974. Her preliminary results were reported in the Journal of the A.A.V. S.O., Vol. 3, p. 59, 1974, where the position given inadvertently refers to another unpublished new variable star and should be corrected to the position given here. Star A in the Figure is BD +43d3442. DORRIT HOFFLEIT Maria Mitchell Observatory Nantucket, Mass., U.S.A.