Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Publications of the Astronomical Society of Australia Publications of the Astronomical Society of Australia Society
Publications of the Astronomical Society of Australia
RESEARCH ARTICLE

Statistical Analysis and the OPEA Model of the White-Light Flares Occurring on Krüger 60B (DO Cep)

Hasan Ali Dal
+ Author Affiliations
- Author Affiliations

Department of Astronomy and Space Sciences, University of Ege, Bornova, 35100 İzmir, Turkey. Email: ali.dal@ege.edu.tr

Publications of the Astronomical Society of Australia 28(4) 365-377 https://doi.org/10.1071/AS11034
Submitted: 3 July 2011  Accepted: 26 September 2011   Published: 7 November 2011

Abstract

In this study, new observations and some results of statistical analyses are presented. The largest flare data set of DO Cep in the literature has been obtained with 89 flares detected in 67.61 hours of U-band flare patrol. First of all, the observations demonstrated that the star is one of the most active flare stars in respect to the computed flare frequency. Secondly, using the independent samples t-test, the detected flares were classified into two subtypes, and then they were modelled. Analysing the models demonstrated that the fast and slow flares occurring on the star can be separated with a critical value of the ratio of their decay time to rise time. The critical value was computed as 3.40. According to this value, the fast flare rate is 20.22%, while the slow flare rate is 79.78%. Besides, there is a 39.282 times difference between the energies of these two types of flares. However, the flare equivalent durations versus the flare rise times increase in similar ways for both groups. In addition, all the flares were modelled with the one-phase exponential association function. Analysing this model, the plateau value was found to be 2.810. Moreover, the half-life value was computed as 433.1 s from the model. The maximum flare rise time was found to be 1164 s, while the maximum flare total duration was found to be 3472 s. The results of the flare timescales indicate that the geometry of the flaring loop on the surface of the star might be similar to those seen on analogues of DO Cep. Consequently, considering both the half-life value and flare timescales, the flares detected on the surface of DO Cep get maximum energy in longer times, while the geometries of the flaring loops or areas get smaller.

Keywords: methods: data analysis — methods: statistical — stars: spots — stars: flare — stars: individual (DO Cep)


References

Benz, A. O. and Güdel, M., 2010, ARA&A, 48, 41
Crossref | GoogleScholarGoogle Scholar |

Contadakis, M. E, Mahmoud, F. M., Mavridis, L. N. and Stavridis, D., 1982, IBVS, 2088, 1

Dal, H. A. and Evren, S., 2010, AJ, 140, 483

Dal, H. A. and Evren, S., 2011a, AJ, 141, 33

Dal, H. A. and Evren, S., 2011b, PASJ, 63, 427

Dawson B. & Trapp R. G. , 2004 , in Basic and Clinical Biostatistics (City: The McGraw-Hill Companies Inc. Press), 61, 134, 245

Doyle, J. G., 1996a, A&A, 307, 162
| 1:CAS:528:DyaK28XisVCgsL4%3D&md5=b176c476de13d09072d498ebf24c6b50CAS |

Doyle, J. G., 1996b, A&A, 307, L45
| 1:CAS:528:DyaK28XivF2itLY%3D&md5=5fcfc28cd455cdbe365d3c8c85ac7b4aCAS |

Favata, F., Flaccomio, E., Reale, F., Micela, G., Sciortino, S., Shang, H., Stassun, K. G. and Feigelson, E. D., 2005, ApJS, 160, 469
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtF2qt73P&md5=ab3360466c7f540331c6d2c6bde12c6fCAS |

Gershberg, R. E., 1972, Ap&SS, 19, 75
Crossref | GoogleScholarGoogle Scholar |

Gershberg R. E. , 2005 , Solar-Type Activity in Main-Sequence Stars (New York: Springer), 53, 191, 192, 194, 211, 325, 360

Gershberg, R. E. and Shakhovskaya, N. I., 1983, Ap&SS, 95, 235
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL3sXmtVejtb8%3D&md5=38199279014f9f4675c0b25f150d47e4CAS |

Glebocki, R. and Gnacinski, P., 2005, yCat., 3244, 0

Green S. B. , Salkind N. J. , & Akey T. M. , 1999 , Using SPSS for Windows: Analyzing and Understanding Data (Upper Saddle River, N.J.: Prentice Hall Press), 50

Grinin V. P. , 1983 , Activity in Red-dwarf Stars, Proc. Seventy-first Colloq., Astrophys. Space Sci. Libr.102, Dordrecht: Reidel, 613

Gurzadian, G. A., 1988, ApJ, 332, 183
Crossref | GoogleScholarGoogle Scholar |

Hardie R. H. , 1962 , in Astronomical Techniques, ed. W. A. Hiltner (Chicago: Univ. Chicago Press), 178a

Haro, G. and Chavira, E., 1955, BOTT, 2l, 3

Haro, G. and Parsamian, E., 1969, BOTT, 5, 45

Henry, T. J., Walkowicz, L. M., Barto, T. C. and Golimowski, D. A., 2002, AJ, 123, 2002

Herr, R. B. and Brcich, J. A., 1969, IBVS, 329, 1

Hudson, H. S. and Khan, J. I., 1997, ASPC, 111, 135

Imanishi, K., Nakajima, H., Tsujimoto, M., Koyama, K. and Tsuboi, Y., 2003, PASJ, 55, 653
| 1:CAS:528:DC%2BD2cXlsl2is7c%3D&md5=e91dee8bd711c2a4404740c8d67d8984CAS |

Ishida, K., Ichimura, K., Shimizu, Y. and Mahasenaputra, , 1991, Ap&SS, 182, 227

Jenkins, J. S., Ramsey, L. W., Jones, H. R. A., Pavlenko, Y., Gallardo, J., Barnes, J. R. and Pinfield, D. J., 2009, A&A, 704, 975
| 1:CAS:528:DC%2BD1MXhsVeru73E&md5=b91ddc176ca2cbfe3027e6c6ec75cb6fCAS |

Kirkup L. & Frenkel R. B. , 2006 , An Introduction to Uncertainty in Measurement (Cambridge: Cambridge University Press)

Kunkel W. , 1967 . An optical study of stellar flare. Thesis. Austin, Texas

Lacy, C. H., Moffett, T. J and Evans, D. S, 1976, ApJS, 30, 85
Crossref | GoogleScholarGoogle Scholar |

Lacy, C. H., 1977, ApJS, 34, 479
Crossref | GoogleScholarGoogle Scholar |

Landolt, A. U., , AJ, 104, 340

Leto, G., Pagano, I., Buemi, C. S. and Rodonó, M, 1997, A&A, 327, 1114

Mavridis, L. N. and Avgoloupis, S., 1986, A&A, 154, 171

Meištas E. G. , 2002 , High-Speed Three-Channel Photometer (HSTCP) User's Guide, To Molétai version (Vilnius: Astronomical Observatory of Vilnius University)

Moffett, T. J., 1974, ApJS, 29, 1
Crossref | GoogleScholarGoogle Scholar |

Motulsky H. , 2007 , in GraphPad Prism 5: Statistics Guide, ed. H. Motulsky (San Diego, CA: GraphPad Software Inc. Press), 94, 133

Nicastro, A. J., 1975, IBVS, 1045, 1

Osawa, K., Ichimura, K., Noguchi, T. and Watanabe, E., 1968, TokAB, ,

Oskanian V. S. , 1969 , in Non-Periodic Phenomena in Variable Stars, Proc. AUI Coll. No 4., ed. L. Detre (Budapest: Academic Press), 131

Pandey, J. C. and Singh, K. P., 2008, MNRAS, 387, 1627
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXpvVWhs78%3D&md5=ef3efa912f1759414f569542b39cf7ddCAS |

Petschek H. E. , 1964 , in Proc. of AAS-NASA Symp. on the Physics of Solar Flares, ed. W. N. Hess, NASA SP-50, 425

Pettersen, B. R., 1991, MmSAI, 62, 217

Pettersen, B. R., Coleman, L. A. and Evans, D. S., 1984, ApJ, 282, 214
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2cXltF2ru7Y%3D&md5=e7f6963f7b045bd0dcfa7714b74f8423CAS |

Reeves, K. K. and Warren, H. P., 2002, ApJ, 578, 590
Crossref | GoogleScholarGoogle Scholar |

Rodonó, M., 1990, IAUS, 137, 371

Schmitt, J. H. M. M. and Liefke, C., 2004, A&A, 417, 651
| 1:CAS:528:DC%2BD2cXkt1altLo%3D&md5=9a465194da6d4648740db01b30f5693eCAS |

Skumanich, A. and McGregor, K., 1986, AdSpR., 6, 151
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXkvVKlsr0%3D&md5=aba213e690b1405b7971d4a8f99ee3d7CAS |

Söderhjelm, S., 1999, A&A, 341, 121

Spanier J. & Oldham K. B. , 1987 , An Atlas of Function (Washington D.C., USA: Hemisphere Publishing Corporation Press), 233

Tamazian, V. S., Docobo, J. A., Melikian, N. D. and Karapetian, A. A., 2006, PASP, 118, 814
Crossref | GoogleScholarGoogle Scholar |

Van Den Oord, G. H. J. and Barstow, M. A., 1988, A&A, 207, 89

Van Den Oord, G. H. J., Mewe, R. and Brinkman, A. C., 1988, A&A, 205, 181

Vandenberg, D. A., Hartwick, F. D. A., Dawson, P. and Alexander, D. R., 1983, ApJ, 266, 747
Crossref | GoogleScholarGoogle Scholar |

Veeder, G. J., 1974, AJ, 79, 702

Vilhu O. , Neff J. E. , & Walter F. M. , 1986 , in New Insight in Astrophysics, ESA SP-263, ed. E. J. Rolfe, 113

Vilhu, O. and Rucinski, S. M., 1983, A&A, 127, 5
| 1:CAS:528:DyaL3sXmt1WrsLw%3D&md5=6c4346c1a7f6bba48cca7dc351a19295CAS |

Walker, A. R., 1981, MNRAS, 195, 1029

Wall J. W. & Jenkins C. R. , 2003 , in Practical Statistics For Astronomers (Cambridge: Cambridge University Press), 79

Wilson, O.C., 1978, ApJ, 226, 379
Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaE1MXks1CitQ%3D%3D&md5=7ceefd836767d3ca61ddb1d390d8bb88CAS |