NGC 4372 / C1223-724 (Updated May 2014) RA: 12:25:45.40 DEC: -72:39:32.4 (J2000) ===================================================================== Bytes Format Explanation 1-8 A8 Star ID 10-32 A11,1x,A11 Position 34-35 A2 Units for position R0 denotes RA, DEC in the J2000 coordinates R5 denotes RA, DEC in the 1950 coordinates XA denotes X, Y in arcseconds XP denotes X, Y in pixels 37-44 F8.4 Period (days) 46-51 F6.3 Mean magnitude (or maximum magnitude if "max" is indicated in the remarks column) 53-57 F5.3 Light amplitude (range of variability) 59 A1 Colour for mean magnitude and amplitude e.g. B, V, R, I, J, K or P (for photographic). 61-65 A5 Type of variable (draft 2006 GCVS classifications) CST denotes non variable stars previously designated as variables 67-80 A19 Notes and Remarks (f denotes field star) "--" or "----" indicates no data available ========================================================================= ID Position Period ampl C Type Notes/ RA/X Dec/Y Units Remarks ========================================================================= 1 12:23:00.61 -72:40:03.0 R0 ---- -- -- L? Note 2 12:28:05.69 -72:45:19.9 R0 ---- -- -- L? Note 3=KK2 12:25:19.29 -72:35:02.3 R0 0.0408 18.24 0.32 V SX 4=KK4 12:26:39.06 -72:35:47.3 R0 0.2418 19.07 0.38 V EW max;f? 5=KK5 12:24:37.10 -72:37:06.5 R0 0.3403 19.07 0.42 V EW max;f? 6=KK6 12:26:18.59 -72:37:40.3 R0 0.0667 17.26 0.33 V SX 7=KK8 12:26:16.08 -72:38:05.6 R0 0.0641 17.67 0.64 V SX 8=KK14 12:25:57.83 -72:38:43.4 R0 0.0564 18.14 0.28 V SX 9=KK15 12:25:08.07 -72:38:47.9 R0 0.0464 18.07 0.26 V SX 10=KK16 12:25:59.52 -72:38:52.2 R0 0.3084 18.03 0.27 V EW max;mem? 11=KK18 12:25:13.05 -72:39:36.8 R0 0.0477 17.44 0.32 V SX 12=KK22 12:25:54.14 -72:39:54.1 R0 0.4150 16.88 0.14 V EW max;mem? 13=KK24 12:25:49.56 -72:40:22.7 R0 3.13 17.08 0.16 V ELL? max 14=KK25 12:25:34.24 -72:40:26.3 R0 0.0597 17.56 0.32 V SX 15=KK27 12:26:59.53 -72:40:49.2 R0 0.3772 17.44 0.56 V EW max;f 16=KK28 12:25:47.48 -72:41:07.0 R0 2.60 17.40 0.6? V EC? max 17=KK29 12:25:46.21 -72:41:49.5 R0 0.0477 17.69 0.43 V SX 18=KK30 12:26:09.51 -72:41:58.1 R0 0.4063 18.32 0.88 V EA max 19=KK31 12:25:09.34 -72:42:58.2 R0 0.3777 17.47 0.45 V EW max;f 20=KK33 12:25:23.34 -72:43:11.6 R0 0.2791 19.09 0.56 V EW max;f 21=KK34 12:26:36.24 -72:43:48.7 R0 ---- 14.37 0.1 V SR? 22=KK35 12:26:18.04 -72:43:55.4 R0 0.2901 17.40 0.69 V EW max;f ====================================================================== Supplementary Notes The BV CM diagram published by Kaluzny & Krzeminski (1993) shows an extended blue HB and a blue straggler sequence. NGC 4372 is a metal poor cluster with [Fe/H] = -2.17 according to the 2010 version of the Harris (1996) catalogue. The RA and dec for V1 and V2 are from Samus et al. (2009) The positions, periods and magnitudes for V3-22 are from Kaluzny & Krzeminski (1993). The membership status for the W Ursa Majoris (EW) variables: V4, 5, 10, 12, 15, 19, 20, 22 are from Rucinski (2000). ======================================================================= Notes on individual stars: V1, V2: McDonald et al. (2013) made spectroscopic observations of these two stars and concluded that they are both cluster members associated with an extended AGB. From ESO archival imagery, they inferred that both stars are long period variables and estimated lower limits to their B, V and I amplitudes: 0.67, 0.49 and 0.23 respectively for V1 and 0.85, 0.81 and 0.46 for V2. ======================================================================= Discovery of the variable stars in NGC 4372: V1-2 Fourcade et al. (1966) with x,y coordinates and an ID chart Both stars are located approximately 12 arcminutes from the cluster centre, well beyond the half-light radius (~4 arcminutes), but inside the tidal radius of~35 arcminutes according to the 2010 update of the Harris (1996) catalogue. V3-22 Kaluzny & Krzeminski (1993) with RA, dec and ID charts These authors identified 36 candidate variable stars which they numbered V1-36. However, only 20 of these proved to be clearly variable and they did not publish any information about the other 16. The 20 "clear" variables were assigned the numbers V3-22 by Clement et al. (2001) in their electronic catalogue. This numbering system was also adopted by Samus et al. (2009). The KK (Kaluzny & Krzeminski 1993) numbers are indicated beside our assigned numbers in the ID column in the above table. -------------------------------------------------------------------------- Kaluzny & Krzeminski (1993) also noted the presence of two faint, blue stars (b1 and b2) that could be hot subdwarfs. Their RA and dec were listed in Table 2 of their paper. --------------------------------------------------------------------- Geraschenko et al. (1997) listed 4 possible RR Lyrae variables, based on their location near the instabiity strip in the CMD. They published an ID chart and derived x,y positions using the coordinate system of Kaluzny & Krzeminski (1993) as a reference frame. -------------------------------------------------------------------- Pietrukowicz et al. (2008) searched for dwarf novae in NGC 4372, but none were detected. Their search was carried out on images obtained on 14 nights in 2004 and 5 in 2005. ------------------------------------------------------------------- Servillat et al. (2008) detected X-ray 10 sources, for which they listed RA and dec, from XMM-Newton observations, none inside the half-mass radius. However, the limiting luminosity of their observations was not constraining for a possible population of faint CVs. =================================================================== References Clement, C. M., Muzzin, A., Dufton, Q., Ponnampalam, T., Wang, J., Burford, J., Richardson, A., Rosebery, T. 2001, AJ, 122, 2587 Fourcade, C. R., Laborde, J. R., Albarracin, J. 1966, Atlas y Catalogue de Estrellas Variables en Cumulos Globulares al sur de -29 degrees, Cordoba Geraschenko, A. N., Kadla, Z. I., Malakhova, Yu. N. 1997, IBVS, 4477 Harris, W. E. 1996, AJ, 112, 1487 Kaluzny, J. & Krzeminski, W. 1993, MNRAS, 264, 785 McDonald, I., Zijlstra, A. A., Rajoelimanana, A. F., John, C. I. 2013, MNRAS, 429, L65 Pietrukowicz, P., Kaluzny, J., Schwarzenberg-Czerny, A., Thompson, I. B., Pych, W., Krzeminski, W., Mazur, B. 2008, MNRAS, 388, 1111 Rucinski, S. M. 2000, AJ, 120, 319 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Servillat, M., Webb, N. A., Barret, D. 2008, A&A, 480, 397 ==========================================================================