A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters. IX. NGC 457

• Autorzy: Moździerski D. , Pigulski A. , Kopacki G. , Kołaczkowski Z. , Stęślicki M.
• Języki publikacji: EN

Abstrakty

EN

We present results of a BVI_C variability survey in the young open cluster NGC 457 based on observations obtained during three separate runs spanning almost 20 years. In total, we found 79 variable stars, of which 66 are new. The BVI_C photometry was transformed to the standard system and used to derive cluster parameters by means of isochrone fitting. The cluster is about 20 Myr old, the mean reddening amounts to about 0.48 mag in terms of the color excess E(B-V). Depending on the metallicity, the isochrone fitting yields a distance between 2.3 kpc and 2.9 kpc, which locates the cluster in the Perseus arm of the Galaxy. Using the complementary Hα photometry carried out in two seasons separated by over 10 years, we find that the cluster is very rich in Be stars. In total, 15 stars in the observed field of which 14 are cluster members showed Hα in emission either during our observations or in the past. Most of the Be stars vary in brightness on different time scales including short-period variability related most likely to g-mode pulsations. A single-epoch spectrum of NGC 457-6 shows that this Be star is presently in the shell phase. The inventory of variable stars in the observed field consists of a single β Cep-type star, NGC 457-8, 13 Be stars, 21 slowly pulsating B stars, seven δ Sct stars, one γ Dor star, 16 unclassified periodic stars, 8 eclipsing systems and a dozen of stars with irregular variability, of which six are also B-type stars. As many as 45 variable stars are of spectral type B which is the largest number in all open clusters presented in this series of papers. The most interesting is the discovery of a large group of slowly pulsating B stars which occupy the cluster main sequence in the range between V=11 mag and 14.5 mag, corresponding to spectral types B3 to B8. They all have very low amplitudes and about half show pulsations with frequencies higher than 3 d^-1. We argue that these are most likely fast-rotating slowly pulsating B stars, observed also in other open clusters.

Słowa kluczowe

EN

open clusters: individual: NGC 457; associations: individual: NGC 457; stars: variables: delta Scuti; stars: oscillations: including pulsations

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2014
• Tom: Vol. 64, No. 2
• Strony: 89--114
• Opis fizyczny: Bibliogr. 86 poz., rys., tab., wykr.

Twórcy

autor

Moździerski D.

• Astronomical Institute, University of Wrocław, Kopernika 11, 51-622, Wrocław

autor

Pigulski A.

• Astronomical Institute, University of Wrocław, Kopernika 11, 51-622, Wrocław

autor

Kopacki G.

• Astronomical Institute, University of Wrocław, Kopernika 11, 51-622, Wrocław

autor

Kołaczkowski Z.

• Astronomical Institute, University of Wrocław, Kopernika 11, 51-622, Wrocław

autor

Stęślicki M.

• Astronomical Institute, University of Wrocław, Kopernika 11, 51-622, Wrocław

Bibliografia

• Alter, G. 1944a, MNRAS, 104, 179.
• Alter, G. 1944b, MNRAS, 104, 191.
• Baade, D. 1983, A&AS, 51, 235.
• Balona, L.A., et al. 2011, MNRAS, 413, 2403.
• Becker, W., and Stock, J. 1954, Zeitschrift für Astrophysik, 34, 1.
• Berger, J. 1962, Annales d’Astrophysique, 25, 1.
• Bertelli, G., Girardi, L., Marigo, P., and Nasi, E. 2008, A&A, 484, 815.
• Bertelli, G., Nasi, E., Girardi, L., and Marigo, P. 2009, A&A, 508, 355.
• Bodén, E. 1946, Uppsala Astron. Obs. Ann., 3, No. 1.
• Bodén, E. 1950, Uppsala Astron. Obs. Ann., 2, No. 8.
• Bodén, E. 1951, Uppsala Astron. Obs. Ann., 2, No. 10.
• Bolte, M. 1991, ApJ, 376, 514.
• Burnichon, M. L. 1975, A&A, 45, 383.
• Caldwell, J.A.R., Cousins, A.W.J., Ahlers, C.C., van Wamelen, P.A., and Maritz, E.J. 1993, SAAO Circ., 15, 1.
• de la Fuente Marcos, R., and de la Fuente Marcos, C. 2009, New Astronomy, 14, 180.
• Diago, P.D., et al. 2009, A&A, 506, 125.
• Dupret, M.-A., Grigahcène, A., Garrido, R., Gabriel, M., and Scuflaire, R. 2004, A&A, 414, L17.
• Eggen, O.J. 1982, PASP, 94, 952.
• Fabregat, J., et al. 1996, A&AS, 119, 271.
• Fitzpatrick, E.L., and Massa, D. 2007, ApJ, 663, 320.
• Fitzsimmons, A. 1993, A&AS, 99, 15.
• Frinchaboy, P.M., and Majewski, S.R. 2008, AJ, 136, 118.
• Gray, R.O., and Corbally, C.J. 1994, AJ, 107, 742.
• Guzik, J.A., Bradley, P.A., Jackiewicz, J., Uytterhoeven, K., and Kinemuchi, K. 2014, Proc. IAU Symp., 301, 63.
• Handler, G., et al. 2007, CoAst, 150, 193.
• Handler, G., et al. 2008, CoAst, 157, 315.
• Harris, G.L.H. 1976, ApJS, 30, 451.
• Hiltner, W.A. 1956, ApJS, 2, 389.
• Hoag, A.A., Johnson, H.L., Iriarte, B., Mitchell, R.I., Hallam, K.L., and Sharpless, S. 1961, Publ. USNO, Second Ser., XVII, 1.
• Hoag, A.A., and Applequist, N.L. 1965, ApJS, 12, 215.
• Huang, W., and Gies, D.R. 2006a, ApJ, 648, 580.
• Huang, W., and Gies, D.R. 2006b, ApJ, 648, 591.
• Huat, A.-L., et al. 2009, A&A, 506, 95.
• Jerzykiewicz, M., Kopacki, G., Pigulski, A., Kołaczkowski, Z., and Kim, S.-L. 2011, Acta Astron., 61, 247.
• Johnson, H.L., Hoag, A.A., Iriarte, B., Mitchell, R.I., and Hallam, K.L. 1961, Lowell Obs. Bull., 5, 133.
• Jones, D.O.M., and Hoag, A.A. 1968, PASP, 80, 531.
• Kharchenko, N.V., Piskunov, A.E., Röser, S., Schilbach, E., and Scholz, R.-D. 2005, A&A, 438, 1163.
• Kohoutek, L., and Wehmeyer, R. 1997, Abhandl. aus der Hamburger Sternwarte, XI, 1 (KW97).
• Kołaczkowski, Z., Pigulski, A., Kopacki, G., and Michalska, G. 2004, Acta Astron., 54, 33.
• Kołaczkowski, Z., et al. 2006, Memorie della Societá Astronomica Italiana, 77, 336.
• Lanz, T., and Hubeny, I. 2007, ApJS, 169, 83.
• Lennon, D.J., Dufton, P.L., and Fitzsimmons, A. 1992, A&AS, 94, 569.
• Lindoff, U. 1968, Arkiv för Astronomii, 5, 1.
• Liu, T., Janes, K. A., and Bania, T. M. 1989, AJ, 98, 626.
• Liu, T., Janes, K. A., and Bania, T. M. 1991, AJ, 102, 1103.
• Loktin, A.V., Gerasimenko, T.P., and Malysheva, L.K. 2001, Astronomical and Astrophysical Transactions, 20, 607.
• Luo, Y. P., Zhang, X. B., Deng, L. C., and Han, Z. W. 2012, ApJ, 746, L7.
• Maciejewski, G., et al. 2008, IBVS, 5864 (Mac08).
• Majewska-Świerzbinowicz, A., Pigulski, A., Szabó, R., and Csubry, Z. 2008, Journal of Physics: Conf. Series, 118, 012068.
• Mathew, B., Subramaniam, A., and Bhatt, B. C. 2008, MNRAS, 388, 1879 (M08).
• Mathew, B., and Subramaniam, A. 2011, Bulletin of the Astronomical Society of India, 39, 517.
• Meingast, S., Handler, G., and Shobbrook, R.R. 2013, A&A, 559, 108.
• Merrill, P. W. 1935, ApJ, 81, 351.
• Mermilliod, J.-C. 1981, A&AS, 44, 467.
• Meynet, G., Mermilliod J.-C., and Maeder, A. 1993, A&AS, 98, 477.
• Miglio, A., Montalbán, J., and Dupret, M.-A. 2007, CoAst, 151, 48.
• Miller W.C., and Merrill, P.W. 1951, ApJ, 113, 624.
• Moffat, A.F.J. 1972, A&AS, 7, 355.
• Moffat, A.F.J., and Vogt, N. 1974, Veroeff. Astron. Inst. Ruhr-Univ. Bochum, 2, 1.
• Morgan, W.W., Code, A.D., and Whitford, A.E. 1955, ApJS, 2, 41.
• Mowlavi, N., Barblan, F., Saesen, S., and Eyer, L. 2013, A&A, 554, 108.
• Moździerski, D., Pigulski, A., Kopacki, G., Stęślicki, M., and Kołaczkowski, Z. 2013, Astrophysics and Space Science Proceedings, 31, Poster No. 9, arXiv:1211.2920.
• Neiner, C., et al. 2009, A&A, 506, 143.
• O’Keefe, J. 1941, ApJ, 94, 353.
• Pesch, P. 1959, ApJ, 130, 764.
• Phelps, R.L., and Janes, K.A. 1994, ApJS, 90, 31.
• Pigulski, A., Jerzykiewicz, M., and Kopacki, G. 1997, Acta Astron., 47, 365.
• Porter, J.M., and Rivinius, T. 2003, PASP, 115, 1153.
• Rivinius, T., Carciofi, A.C., and Martayan, C. 2013, The Astronomy and Astrophysics Review, 21, 69.
• Saesen, S., et al. 2010a, A&A, 515, 16.
• Saesen, S., et al. 2010b, Astron. Nachr., 331, 1080.
• Saesen, S., Briquet, M., Aerts, C., Miglio, A., and Carrier, F. 2013, AJ, 146, 102.
• Saio, H. 2013, Lecture Notes in Physics, 865, 159.
• Schild, R., and Romanishin, W. 1976, ApJ, 204, 493 (SR76).
• Sowell, J.R. 1987, ApJS, 64, 241.
• Štefl, S., et al. 2009, A&A, 504, 929.
• Stetson, P.B. 1987, PASP, 99, 191.
• Tadross, A.L. 2001, New Astronomy, 6, 293.
• Tadross, A.L. 2003, New Astronomy, 8, 737.
• Torrejón, J.M., Fabregat, J., Bernabeu, G., and Alba, S. 1997, A&AS, 124, 329 (T97).
• Trumpler, R.J. 1930, Lick Observatory Bulletin, 14, 154.
• Udalski, A., and Pych, W. 1992, Acta Astron., 42, 285.
• Uytterhoeven, K., Poretti, E., Rodríguez, E., De Cat, P., Mathias, P., Telting, J.H., Costa, V., and Miglio, A. 2007, A&A, 470, 1051.
• Walker, G.A.H., et al. 2005, ApJ, 635, 77.
• Zacharias, N., et al. 2010, AJ, 139, 2184.
• Zhang, X.B., Luo, C.Q., and Fu, J.N. 2012, AJ, 144, 86 (Zha12).