SX Phoenicis Stars in the Globular Cluster M 92

• Autorzy: Kopacki G.
• Języki publikacji: EN

Abstrakty

EN

We present results of a search for SX Phe stars in the globular cluster M 92. In photometric reductions, we used the image subtraction method supplemented with a procedure of searching for short-period variables, based on the examination of each pixel in the CCD frame. In addition to two SX Phe stars already known in the cluster, we have found five new variables of this type. One SX Phe variable, v34, shows double-mode pulsation with a period ratio equal to 0.741 or 0.790. The second value would indicate oscillations in radial fundamental and first overtone modes. Combining our ground based data and the WFPC HST observations, we determine the average V magnitudes and (V-I_C) colors for three SX Phe stars. Moreover, from an estimate of the scatter in the HST data of all observed blue stragglers we suspect three stars to be variable.

Słowa kluczowe

EN

Stars: Population II; globular clusters: individual: M 92

• Wydawca: Copernicus Foundation for Polish Astronomy
• Czasopismo: Acta Astronomica
• Rocznik: 2007
• Tom: Vol. 57, No. 1
• Strony: 49--60
• Opis fizyczny: Bibliogr. 12 poz., rys., tab., wykr.

Twórcy

autor

Kopacki G.

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

Bibliografia

• Alard, C., and Lupton, R.H. 1998, Astrophys. J., 503, 325.
• Clement, C.M., et al. 2001, Astron. J., 122, 2587.
• Dolphin, A.E. 2000a, P.A.S.P., 112, 1383.
• Dolphin, A.E. 2000b, P.A.S.P., 112, 1397.
• Jeon, Y-B., et al. 2004, Astron. J., 128, 287.
• Kopacki, G. 2001, Astron. Astrophys., 369, 862.
• Kopacki, G. 2005, Acta Astron., 55, 85.
• Kopacki, G., Kołaczkowski, Z., and Pigulski, A. 2003, Astron. Astrophys., 398, 541.
• Olech, A., et al. 2005, MNRAS, 363, 40.
• Rodríguez, E., and López-González, M.J. 2000, Astron. Astrophys., 359, 597.
• Santolamazza, P., et al. 2001, Astrophys. J., 554, 1124.
• Schwarzenberg-Czerny, A. 1996, Astrophys. J. Letters, 460, L107.