Abstract
XY Leo (BD+18° 2307, p = 0d .28) was observed each season from 1992 through 1995 at Yunnan Observatory with the 1 m telescope and 37 new heliocentric times of minimum light were determined. The newly expanded database of the minimum times,including these new epochs, definitely confirm the sine-like variation of its O–C values. Observations and analyses strongly supported the viewpoint that the variation of the O–C values of the minimum times is mainly caused by the light- time effect. Based on this newly expanded database, new light elements for the eclipsing system XY Leo and new light-time orbit for this complex system have been obtained with much better accuracy than before by means of the least squares fitting to the light-time equation. It's also noted that the additional period variation for XY Leo probably may not be ruled out besides the light-time effect. The method of analysis and the discussion of the results are presented in this paper.
Similar content being viewed by others
References
Applegate, J.H.: 1992, Astrophys. J. 385, 621.
Barden, S.C.: 1987, Astrophys. J. 317, 333.
Cruddace, R.G. and Dupree, A.K.: 1984, Astrophys. J. 277, 263.
Gehlich, U.K., Prölss, J. and Wehmeyer, R.: 1972, Astron. Astrophys. 18, 477.
Hilditch, R.W.: 1981, Mon. Not. R. Astron. Soc. 196, 305.
Hill, G., Hilditch, R.W., Younger, F. and Fisher, W.A.: 1975, Mem. Roy. Astron. Soc. 79, 131.
Hrivnak, B.J., Milone, E.F., Hill, G. and Fisher, W.A.: 1984, Astrophys. J. 285, 683.
Hrivnak, B.J.: 1985, Astrophys. J. 290, 696.
Irwin, J.B.: 1952, Astrophys. J. 116, 211.
Kalużny, J. and Pojmański, G.: 1983, Acta Astron. 33, 277.
Keskin, V. and Pohl, E.: 1989, Inf. Bull. Variable Stars, No. 3355.
Koch, R.H.: 1960, Astron. J. 65, 374.
Koch, R.H. and Shanus, C.R.: 1978, Astron. J. 83, 1452.
Kreiner, J.M.: 1977, Period Changes of W Urase Majoris Stars, in: R. Kippenhaln, J. Rahe and W. Strohmeier (eds), The Interaction of Variable Stars with Their Environment, IAU Colloq. No.42, Bamberg, pp. 393–397.
Krzesinski, J., Kuczawska, E. and Kurpinska, M.: 1990, Inf. Bull. Variable Stars, No. 3458.
Kuszewski, A.: 1966, Adv. Astron. Astrophys. 4, 233.
Kwee, K.K. and van Woerden, H.: 1956, Bull. Astron. Inst. Netherlands 12, 327.
Liu, Q. and Zhang, J.: 1982, Acta Astrophys. Sin. 2, 131. (in Chinese)
McGale, P.A., Pye, J.P. and Hodgkin, S.T.: 1996, Mon. Not. R. Astron. Soc. 280, 627.
Mullis, C.R. and Faulkner, D.R.: 1991, Inf. Bull. Variable Stars, No. 3593.
Pohl, E. and Kizilirmak, A.: 1977, Inf. Bull. Variable Stars, No. 1358.
Van' t Veer, F.: 1986, Astron. Astrophys. 156, 181.
Vilhu, O. and Heise, J.: 1986, Astrophys. J. 311, 937.
Wunder, E., Wieck, M., Kilinc, B., Gülmen, Ö., Tunca, Z. and Evren, S.: 1992, Inf. Bull. Variable Stars, No. 3760.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Pan, L., Cao, M. Study on the Period Changes of xy Leonis. Astrophysics and Space Science 259, 285–293 (1998). https://doi.org/10.1023/A:1001741522098
Issue Date:
DOI: https://doi.org/10.1023/A:1001741522098