DOI QR코드

DOI QR Code

PHOTOMETRIC STUDY OF THE NEAR-CONTACT BINARY CN ANDROMEDAE

  • Lee Chung-Uk ;
  • Lee Jae-Woo
  • Published : 2006.03.01

Abstract

We completed four color light curves of the near-contact binary CN And during three nights from September to December 2004 using the 61-cm reflector and BV RI filters at Sobaeksan Observatory. We determined four new times of minimum light (two timings for primary eclipse, two for secondary). Newly obtained BV RI light curves and the radial velocity curves from Rucinski et a1. (2000) were simultaneously analyzed to derive the system parameters of CN And. We used the semi-detached mode 4 of the 2003-version of the Wilson-Devinney binary model, and interpreted the asymmetry of the light curve by introducing two spots; a cool spot on the primary component and a hot spot on the secondary component. New photometric parameters are not much different from those of Cicek et a1. (2005), and it is considered that the system is in the era of broken contact. From the orbital period study with all available timings including our data, we found a continous period decrease with a rate of $P_{obs}=--1.82{\times}10^{-7}\;d\;yr^{-1}$ that can be explained with two possible mechanisms. We think the most likely cause of the period decrease is a thermal mass transfer from the primary to the secondary component, rather than angular momentum loss due to a magnetic stellar wind.

Keywords

binaries;close-star;individual (CN Andromedae);stars;mass transfer

References

  1. Bozkurt, S., Gulmen, O., Ibanoglu, C., & Gudur, N., 1976, Photoelectric Light-Curves of CN And, IBVS, 1087
  2. Branly, R. M., 1992, A Photometric Study of AK Herculis and CN Andromedae, Master's thesis, Stephan F. Austin State Univ
  3. de Jager, C. & Nieuwenhuijzen, H., 1987, A new determination of the statistical relations between stellar spectral and luminosity classes and stellar effective temperature and luminosity, A&A, 177, 217
  4. Dempsey, R. C., Linsky, J. L., Fleming, T. A., & Shmitt, J. H. M. M., 1993, Observations of the CA II infrared triplet in chromospherically active single and binary stars, ApJS, 86, 599 https://doi.org/10.1086/191791
  5. Evren, S., Ibanoglu, C., Tunca, Z., Akan, M. C., & Keskin, V., 1987, The 1986 Observations and the Period Study of CN Andromedae, IBVS, 3109
  6. Flannery, B. P., 1976, A Cyclic Thermal Instability in Contact Binary Stars, ApJ, 205, 217 https://doi.org/10.1086/154266
  7. Guinan, E. F. & Bradstreet, D. H., 1988, in Formation and Evolution of Low Mass Stars, eds. A. K. Dupree and M. T. V. T. Lago (Dordrecht: Kluwer), 345
  8. Hoffmeister, C., 1949, Die RW Aurigae-Sterne und ihre Nebenformen, AN, 12, 1
  9. Keskin, V., 1989, Light changes of the close binary system CN Andromedae , Ap&SS, 153, 191
  10. Kim, S.-L., Kyung, J.-M., Kwon, S.-G., & Yoon, J.-H., 2001, An Observational Program for the SOAO 2K CCD Camera, PKAS, 16, 37
  11. Kreiner, J. M., Kim, C.-H., & Nha, I.-S., 2001, An Atlas of O-C Diagrams of Eclipsing Binary Stars (Krakow: Wydawn. Nauk. Akad. Pedagogicznej)
  12. Kwee, K. K & van Woerden, H., 1956, Bull. Astron. Inst. Netherlands, A method for computing accurately the epoch of minimum of an eclipsing variable, 12, 327
  13. Lee, C.-U., Park, S.-S., Kim, C.-H., & Byun, Y.-I., 2003, A Construction of a Small Semi-automatic Telescope for Eclipse Timing Observations of Eclipsing Binary stars, Journal of Astronomy & Space Science, 20, 143 https://doi.org/10.5140/JASS.2003.20.2.143
  14. Lochel, K., 1960, Mitteilungen Uber Veranderliche Sterne, 457-458
  15. Lucy, L. B., 1976, Mass Loss by Cool Carbon Stars, ApJ, 205, 208 https://doi.org/10.1086/154265
  16. Paczynski, B., 1971, Evolutionary Processes in Close Binary Systems, ARA&A, 9, 183 https://doi.org/10.1146/annurev.aa.09.090171.001151
  17. Pringle, J. E., 1975, Period changes in eruptive binaries, MNRAS, 170, 633 https://doi.org/10.1093/mnras/170.3.633
  18. Rafert, J. B., Markworth, N. L., & Michaels, E. J., 1985, Photoelectric observations of CN Andromedae - an unusual overcontact binary, PASP, 97, 310 https://doi.org/10.1086/131537
  19. Robertson, J. A. & Eggleton, P. P., 1977, The infrared variability and nature of symbiotic stars, MNRAS, 179, 359 https://doi.org/10.1093/mnras/179.3.359
  20. Rucinski, S. M., 1969, The Photometric Proximity Effects in Close Binary Systems. I. The Distortion of the Components and the Related Effects in Early Type Binaries, A&A, 19, 245
  21. Rucinski, S. M., Lu, W., & Mochnacki, S. W., 2000, Radial Velocity Studies of Close Binary Stars. III, AJ, 120, 1133 https://doi.org/10.1086/301458
  22. Samec, R. G., Laird, H., Mutzke, M., & Faulkner, D. R., 1998, DBV Observations of the Solar-Type Near Contact Binary, CN Andromedae, IBVS, 4616
  23. Seeds, M. A. & Abernethy, D. K., 1982, Photoelectric observations of CN Andromedae, PASP, 94, 1001 https://doi.org/10.1086/131099
  24. Van Hamme, W., 1993, New limb-darkening coefficients for modeling binary star light curves, AJ, 106, 2096 https://doi.org/10.1086/116788
  25. Van Hamme, W., Samec, R. G., Gothard, N. W., Wilson, R. E., Faulkner, D. R., & Branly, R.. M., 2001, CN Andromedae: A Broken-Contact Binary?. AJ, 122, 3436 https://doi.org/10.1086/324110
  26. Webbnik, R. F., 1976, The evolution of low-mass close binary systems. I - The evolutionary fate of contact binaries, ApJ, 209, 829 https://doi.org/10.1086/154781
  27. Wilson, R. E. & Devinney, E. J., 1971, Realization of Accurate Close-Binary Light Curves: Application to MR Cygni, ApJ, 166, 605 https://doi.org/10.1086/150986
  28. Yang, Y. & Liu, Q., 1985, A Flare on the Contact Binary CN And. IBVS. 2705
  29. Shaw, J. S., Caillault, J. P., & Schmitt, J. H. M. M., 1996, Near-Contact Binary Systems in the ROSAT All-Sky Survey, ApJ, 461, 951 https://doi.org/10.1086/177116
  30. Kaluzny, J., 1983, CN And - W UMa-type system in the phase of poor thermal contact?, AcA, 33, 345
  31. Shaw, J. S., 1994, Near-contact binaries, MmSAI, 65, 95
  32. Lucy, L. B., 1967, Gravity-Darkening for Stars with Convective Envelopes, Zeitschrift fur Astrophysik, 65, 89
  33. Cicek, A., Erdem, A., & Soydugan, F., 2005, A near-contact binary: CN Andromedae, AN., 326, 127

Cited by

  1. WZ CYGNI: A MARGINAL CONTACT BINARY IN A TRIPLE SYSTEM? vol.142, pp.1, 2011, https://doi.org/10.1088/0004-6256/142/1/12
  2. CN Andromedae: a shallow contact binary with a possible tertiary component vol.19, pp.1, 2019, https://doi.org/10.1088/1674-4527/19/1/10