COMMISSION 27 OF THE I. A. U. INFORMATION BULLETIN ON VARIABLE STARS Number 2219 Konkoly Observatory Budapest 1982 November 1 HU ISSN 0374-0676 HISTORICAL LIGHT CURVES OF FOUR T TAURI STARS I have examined the archival plate collection at the Harvard College Observatory to obtain the historical light curves of SY Cha, TW Cha, VZ Cha, and DR Tau. This study was designed to look for periodic photometric variation (and hence rotation periods) as first suggested by Mathieu and Fich (1982). The reason for choosing the Table I J.D.minus TW SY VZ J.D.minus TW SY VZ 2,400,000 Cha Cha Cha 2,400,000 Cha Cha Cha 25986.572 13.9 14.3 13.7 27649.226 13.9 >14.1 14.1 26057.312 14.1 14.3 13.8 27811.468 ---- ---- 13.4 26067.434 ---- ---- 13.5 27874.505 ---- 14.2 14.4 26071.395 ---- ---- 13.9 27930.272 13.7 14.1 13.5 26086.308 14.4 14.2 14.2 27960.257 14.4 14.3 14.2 26092.479 13.9 14.3 14.3 27960.347 14.5 14.2 14.3 26096.348 13.9 14.3 >14.3 27978.196 14.0 14.1 13.5 26118.219 14.0 14.3 14.5 27982.347 14.0 ---- >14.1 26144.220 13.8 14.3 14.1 28257.517 14.0 13.3 13.7 26144.286 13.9 14.3 14.4 28260.599 13.9 >14.1 >14.2 26366.423 ---- 13.7 13.7 28307.240 13.9 13.9 14.3 26399.461 14.2 14.0 13.9 28307.318 13.5 14.0 14.1 26456.286 13.8 14.0 >14.5 28327.226 14.3 14.3 12.9 26472.352 14.4 14.4 14.8 28336.228 13.6 14.1 >14.5 26481.344 13.6 14.5: 13.8 28339.312 13.4 14.1 14.3 26486.220 14.1 14.4 13.3 28342.229 13.7 14.0 14.1 26486.288 14.2 14.0 13.5 28357.234 14.0 14.1 13.2 26486.349 ---- ---- 13.4 28387.232 14.5 14.1 13.8 26504.338 ---- ---- 13.8 28486.535 13.9 14.3 13.8 26505.328 14.1 14.2 13.9 28598.446 13.9 14.4 14.6 26539.222 14.0 14.2 13.5 28639.411 14.4 14.3 14.1 26769.461 13.0 13.5 14.0 28639.496 14.3 14.2 13.9 26805.445 14.2 13.9 14.6 28670.318 14.4 14.8 14.8 26811.426 ---- ---- 13.2 28694.228 13.9 14.3 14.1 26839.373 14.0 14.3 >14.3 28694.312 14.1 14.4 14.1 26918.223 14.2 >14.3 >14.2 28721.234 14.0 14.2 14.2 27186.380 14.4 14.2 13.7 28770.239 14.1 >14.1 14.1 27523.299 14.1 14.5 14.1 28878.552 14.6 14.4 13.4 27524.348 14.1 13.5 >14.0 28912.558 14.2 14.2 14.4 27546.295 14.3 13.7 14.3 28968.505 14.0 14.3 13.7 27570.236 14.0 14.1 13.8 28993.491 14.1 14.1 >14.1 27631.227 >14.4 14.1 13.8 29001.480 13.5 ---- 13.9: Table I (cont.) J.D.minus TW SY VZ J.D.minus TW SY VZ 2,400,000 Cha Cha Cha 2,400,000 Cha Cha Cha 29014.327 14.3 14.2 14.4 29349.346 --- 12.7 14.1 29014.411 14.1 14.1 14.3 29374.410 14.2 14.2 14.2 29018.318 14.2 14.3 13.8 29374.494 14.1 ---- 13.9 29018.424 14.1 14.1 13.9 29382.275 14.4 14.5 13.4 29022.462 14.4 14.0 13.8 29399.228 14.1 14.0 13.6 29042.402 14.3 14.0 14.2 29399.316 14.2 14.4 14.1 29046.336 13.9 14.0 14.2 29403.380 14.2 14.3 13.7 29049.248 14.1 14.0 14.3 29407.264 13.5 14.3 13.5 29049.334 14.2 14.2 14.3 29410.329 14.1 14.4 12.8 29049.376 14.3 14.2 14.2 29410.351 14.5 14.2 13.2 29073.357 14.0 14.3 13.6 29419.217 13.0 14.2 13.7 29077.255 13.9 >14.0 14.2 29428.331 14.4 14.2 14.2 29079.252 14.2: >14.3 14.5 29435.227 14.2 14.4 14.2 29079.295 ---- ---- 14.2 29435.312 14.0 14.4 ---- 29101.281 14.5 14.1 13.8 29463.230 14.6 14.3 13.6 29125.236 14.1 >14.2 14.2 29471.245 14.5 14.3 14.1 29222.539 14.1 14.1 14.1 29480.326 ---- ---- 13.8 29266.543 14.6 14.3 14.1 29620.538 14.3 14.3 14.0 29341.420 14.5 14.3 13.5 29666.466 14.3 14.0 14.2 Table II J.D.minus SY J.D.minus SY J.D.minus SY 2,400,000 Cha 2,400,000 Cha 2,400,000 Cha 15498.598 14.2 30852.363 14.1 43613.687 14.1 18043.605 13.9 30915.237 14.3 43615.525 14.3 18456.572 14.5 31109.555 14.1 43616.689 14.3 22105.512 14.4 31286.235 14.4 43694.498 14.0 22112.503 >14.2 31478.490 14.1 43899.772 >13.7 25594.496 14.0 31593.233 14.3 43901.748 >14.1 25626.478 14.3 31647.236 14.2 43901.821 >13.8 25650.543 14.0 31970.230 14.0 43902.753 14.1 25689.458 14.2 32005.236 14.4 44018.625 14.1 25710.369 14.0 32021.236 14.2 44020.545 13.0 25731.293 14.5 32276.536 14.5 44021.539 14.1 25759.214 14.5 32317.313 14.2 44021.667 14.5 25776.213 >14.1 32384.237 14.0 44023.703 14.1 29696.359 14.4 32593.412 13.9 44638.989 >13.7 29716.462 13.6 32626.517 14.2 44643.986 13.9 29731.393 14.0 32670.214 14.5 44647.040 14.0 29764.197 14.3 32702.229 14.3 44663.969 14.1 29811.210 14.2 33000.359 14.4 44673.052 14.1 29819.233 14.3 33041.233 14.4 44674.059 14.2 29823.213 14.4 33070.271 13.9 44694.957 14.3 30004.491 14.0 33091.232 14.4 44699.891 >13.7 30057.515 14.5 33099.320 14.2 44700.007 13.8 30061.473 14.2 33125.235 14.0 44727.892 >14.2 30085.456 14.3 33308.539 14.1 44727.984 14.2 30106.393 14.5 33409.383 14.5 44749.828 14.3 30117.400 14.4 33477.237 14.5 44994.029 14.0 30134.409 14.2 33664.558 14.2 45054.957 14.5 30178.213 14.3 33834.300 14.5 45073.889 14.0 30198.235 14.5 34099.466 14.4 45085.986 14.1 30436.355 14.5 43613.640 14.2 Table III J.D.minus DR J.D.minus DR J.D.minus DR 2,400,000 Tau 2,400,000 Tau 2,400,000 Tau 42427.635 11.7 43214.526 13.9 44192.724 11.5 42452.552 11.5 43397.842 >14.0 44222.607 12.5 42716.838 12.1 43399.579 12.2 44247.612 12.1 42745.690 12.5 43427.864 13.4 44273.530 12.2 42748.671 12.6 43438.813 14.4 44274.542 12.2 42754.710 11.8 43459.788 12.5 44283.610 13.6 42754.767 11.9 43462.688 12.2 44549.772 11.2 42770.590 12.0 43480.698 13.2 44549.835 11.2 42779.643 12.4 43482.717 12.8 44577.669 11.2 42783.552 12.1 43540.522 11.4 44577.700 11.8 42798.599 12.2 43542.538 12.0 44607.589 11.2 42806.535 12.2 43550.583 12.7 44607.619 11.7 42811.555 12.2 43567.508 12.6 44630.545 12.1 42829.528 12.2 43568.505 12.3 44630.573 12.2 43043.851 12.5 43754.846 11.5 44663.510 11.8 43044.806 11.8 43791.848 12.2 44665.505 12.2 43044.861 11.4 43792.849 12.1 44672.894 12.0 43046.569 12.9 43814.745 12.2 44673.924 11.2 43074.768 13.2 43814.772 12.3 44872.884 11.2 43078.787 14.0 43840.716 12.4 44908.796 11.8 43097.675 12.2 43840.742 12.5 44911.762 11.4 43099.781 12.2 43870.613 11.1 44933.641 12.0 43126.664 12.1 43870.637 11.4 44939.627 11.9 43155.560 12.1 43921.538 12.4 44955.623 11.4 43166.593 12.1 43922.548 13.1 44955.649 11.5 43166.651 12.0 43922.580 12.6 44985.585 12.1 43182.569 12.8 43933.542 11.2 44985.638 12.1 43192.531 13.2 44136.761 12.2 44994.598 11.9 43193.512 12.7 44172.797 12.8 44994.621 11.9 43193.567 12.9 44192.696 11.5 45044.511 11.8 first three stars for examination was the reports of periodicities by Mauder and Sosna (1975) and Kappelmann and Mauder (1981). B, V, and R observations of SY Cha during 1970-2 will be reported by Schaefer (1982). During this period, SY Cha brightened and showed strictly periodic oscillations with a 1.6m amplitude. DR Tau showed a similar brightening in the 1970's (Chavarria-K. 1979), so it is of interest to look for oscillations during its "outburst". Additional observations of DR Tau after 1975 are given in Kuan (1976), Bertout et al. (1977), Bastian and Mundt (1979), Cohen and Kuhi (1979), Chavarria-K. (1979), and Gotz (1982). All plates that I examined were from the A, MF, RB, or Damon series and are in the B magnitude system. The magnitudes (see Tables I- III) were estimated visually, so the one sigma error is roughly 0.20m. The sequence of comparison stars for DR Tau was taken from Gotz (1982). The Chamaeleon sequence was derived from measurements of the stars in Selected Area SA203. I have performed a Fourier Transform on the data for the various stars and find no significant periodicities between 0.7d and 100.0d. BRADLEY E. SCHAEFER Massachusetts Institute of Technology Cambridge, Mass. 02139 USA References: Bastian, U. and Mundt, R. 1979, Astron. Astrophys. Supp. 36, 57. [BIBCODE 1979A&AS...36...57B ] Bertout, C., Krautter, J., Mollenhoff, C. and Wolf, B. 1977, Astron. Astrophys. 61, 737. [BIBCODE 1977A&A....61..737B ] Chavarria-K., C. 1979, Astron. Astrophys. 79, L18. [BIBCODE 1979A&A....79L..18C ] Cohen, M. and Kuhi, L.V. 1979, AP. J. Supp. 41, 743. [BIBCODE 1979ApJS...41..743C ] Gotz, W. 1982, I.B.V.S. no. 2172. Kappelmann, N. and Mauder, H. 1981, ESO Messenger no. 23, 18. [BIBCODE 1981Msngr..23...18K ] Kuan, P. 1976, Ap. J. 210, 129. [BIBCODE 1976ApJ...210..129K ] Mauder, H. and Sosna, F.M. 1975, I.B.V.S. no. 1049. Mathieu, R. and Fich, M. 1982, Bull. A.A.S. 14, 38. Schaefer, B.E. 1982, submitted to Ap. J. Lett. [BIBCODE 1983ApJ...266L..45S ]