COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS NUMBER 404 Konkoly Observatory Budapest 1969 November 12 OBSERVATIONS OF UV Cet DURING THE INTERNATIONAL CAMPAIGN OCTOBER 3-18, 1969 The flare star UV Cet was observed at our Observatory for 11.5 hours during the last session of the international campaign organized by the Working Group on flare stars (Andrews et al., 1968). The intervale of the effective time coverage are given in Table 1. According to the recommendations to flare star observers contained in Inf.Bull.var. Stare no 328, only interruptions longer than one minute are noted, But, we should like to point out that some flares of UV Cet last about one minute or less, and so it should be more suitable to notice the interruptions of more than half a minute. In Table 2 we give the data referring to the nine observed flares. The integrated intensity P=Integral(I_(o+f)-I_o)/I_o dt of the flare no.2 enclosed in brackets is a minimum value because the final part of the flare was lost. The light curves of the observed flares are shown in the Figures. When the observations are missing,even for short intervals the corresponding part of the flare light curves are drawn with a broken line. The notations in the tables are the same as in IBVS No.403. As is known,UV Cet is the B component of the visual binary system L 726-8. The angular distance of the two components is less than 2",therefore the total light intensity of the system (I_A+I_B) was measured. According to the B magnitudes given by Petit (1961) in his catalogue (m_A = 14.1, m_B = 14.71) we corrected the observed intensities using the following equation: I_[B(W Cet)] = 0.38(I_A + I_B) Regarding the flare activity of W Cet (number of flare events per hour of observation) we note that it was higher during the 1968 campaign than during the 1969 campaign. 0n the other hand, if we consider the integrated intensity, P. as another activity indicator, the situation is reversed, as is shown in the following Table: Hours of Frequency Mean integr. Campaign observations of flares intensity per hour per hour 1968 51.2 1.3 1m2 1969 11.5 0.8 3.5 Mr. R.Barbagallo and Mr. V.Stancanelli have collaborated in the observations. Table 1 Intervals of the effective time coverage (Interruptions less than one minute are not noted) Date Oct Coverage (U.T.) TC m_lim_+ -m_0 1969 03 00h02-0022; 0024-0049; 0051-0059; 0102-0108; 0123-0144; 80m 1.9 04 2151-2205; 2208-2230; 2234-2247; 2249-2253; 2257-2303; 2305-2308; 2314-2317; 2319-2321; 2329-2338; 2352-2359; 05 0007-0028; 0029-0035; 0108-0130; 0133-0143; 0145-0155; 0156-0217; 0228-0233; 0235-0243; 0255-0302; 0304-0306; 195 2.2 06 2220-2236; 2238-2246; 2259-2304; 2307-2334; 2337-2342; 2349-2354; 07 0007-0009; 0028-0034; 0050-0054; 0056-0057; 0059-0110; 0120-0125; 0127-0130; 0131-0148; 0155-0220; 0222-0243; 0246-0300; 0303-0313; 0316-0322; 0324-0330; 0334-0338. 201 2.2 16 2217-2240; 2242-2342; 2346-2400; 17 0000-0002; 0008-0018; 0020-0025; 0027-0118; 0127-0204; 0208-0219; 213 3.3 Total coverage 11.5h [FIGURE 1] [FIGURE 2] [FIGURE 3] Table 2. Observed flares No Date Oct t_b t_max t_e m_1-m_0 (m_1 -m_0)m P sky 1969 1 03 00h14.1m 00h14.15m 00h15.6m 1.9m -0.30m 0.63 2 2 03 01 40.1 01 40.3 ? 1.9 -3.68 (14.10) 3 3 04 21 53.2 21 53.3 21 59.0 2.2 -2.32 5.10 2 4 05 01 39.3 01 39.5 01 45.0 2.2 -2.44 3.30 2 5 06 22 22.0 22 22.1 22 27.0 2.2 -2.75 3.54 2 6 07 01 33.0 01 33.05 01 34.2 2.5 -1.23 0.75 2 7 16 23 17.3 23 18.8 23 24.5 3.6 +0.92 2.20 1 8 16 23 25.3 23 25.35 23 28.0 3.8 +1.70 0.66 1 9 17 01 40.3 01 40.4 01 51.0 3.1 -2.72 10.23 2 References Andrews, A.D. Chugainov, P.F., Gershberg, R.E., Oskanian V.S., 1968, Comm.27 IAU, Inf.Bull.var.Stars, No. 318. Petit,M., 1961, J.Observateurs, 44 11. [BIBCODE 1961JO.....44...11P ] Catania Astrophysical Observatory, Italy October 31, 1989 S. CRISTALDI M. RODONO