NGC 6144 / C1624-259 (Updated March 2013) RA: 16:27:13.86 DEC: -26:01:24.6 (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 16:27:49.05 -26:02:43.8 R0 ---- 15.2 1.6 P IN f;BPSco 2 16:27:25.34 -26:06:53.6 R0 ---- 15.35 1.3 P IN: f;BOSco ======================================================================== Supplementary Notes Neely et al. (2000) pointed out that the cluster is located in the region of the Rho Ophiuchus dust cloud and it seems that both of the variables are irregular, eruptive variables associated with the nebula. The RA and dec in the above table are from Samus et al. (2009). The remaining data are from the GCVS, based on the study of Satyvoldiev (1982). V1 shows short term variations. ======================================================================== Discovery of the variable stars in NGC 6144: V1 = BP Sco Sawyer (1953) with x,y coordinate V2 = BO Sco Liller (1983) with x,y coordinates and an ID chart for V1 and V2 Liller recovered Sawyer's V1 and found that Sawyer's previously published y coordinate was incorrect. -------------------------------------------------------- Sarajedini et al. (2007) published a V-I color magnitude diagram which shows a blue HB and a well defined blue straggler sequence. Some of the blue stragglers are probably variable but a variability search has not been carried out. Because the HB is populated only on the blue side of the instability strip, it is not surprising that no RR Lyrae variables have been detected. ======================================================================== References Liller, M. H. 1983, AJ, 88, 404 Neely, R. K., Sarajedini, A., Martins, D. H. 2000, AJ, 119, 1793 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Sarajedini, A., Bedin, L. R., Chaboyer, B., Dotter, A., Siegel, M., Anderson, J., Aparicio, A., King, I., Majewski, S., Marin-Franch, A., Piotto, G., Reid, I. N., Rosenberg, A. 2007, AJ, 133, 1658 Satyvoldiev, V. 1982, Per Zvez Pril 4, N20, 127 Sawyer, H. B. 1953, JRASC, 47, 229 =======================================================================