NGC 6541 / C1804-437 (Updated June 2016)) RA: 18:08:02.36 DEC: -43:42:53.6 (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 18:08:04.58 -43:45:00.0 R0 237.0 13.95 3.5 V M Note 2 18:08:10.67 -43:43:05.2 R0 0.517 16.1 1.2 B RR0 3 18:07:56.31 -43:52:47.6 R0 ---- 16.5 1.0 B RR f?;Note 4 18:08:34.78 -43:54:42.7 R0 0.741 15.3 1.0 B RR0 f 5 18:07:46.05 -44:02:25.0 R0 0.629 15.15 1.5 B RR0 f;Note 6 18:07:19.33 -43:27:47.3 R0 0.447 15.9 1.8 B RR0 f 7 18:09:08.46 -43:30:20.9 R0 0.473 15.9 1.4 B RR0 f 8 18:07:01.35 -44:00:45.1 R0 0.3044 17.3 0.8 B RR1 f 9 18:08:03.36 -43:42:07.2 R0 0.26 18.11 0.45 V EW WU1 10 18:07:59.76 -43:43:55.2 R0 0.20 17.68 0.12 V EW WU2 11 18:08:01.20 -43:42:00.0 R0 ---- 18.08 0.23 V EW WU3 12 18:08:00.48 -43:42:39.6 R0 0.050 17.67 0.26 V SX SX1 13 18:08:03.12 -43:42:03.6 R0 0.046 17.40 0.13 V SX SX2 14 18:08:01.68 -43:42:50.4 R0 0.0647 17.20 0.44 V SX SX3;Note 15 18:08:01.44 -43:42:54.0 R0 0.041 17.95 0.07 V SX SX4 16 18:08:01.68 -43:43:12.0 R0 0.065 17.11 0.26 V SX SX5 17 18:08:03.36 -43:43:01.2 R0 0.0425 17.70 0.20 V SX SX6 18 18:08:03.12 -43:43:12.0 R0 0.032 18.12 0.13 V SX SX7 19 18:08:01.92 -43:42:07.2 R0 0.046 17.87 0.08 V SX SX8 20 18:07:53.12 -43:43:04.8 R0 0.059 17.14 0.29 V SX SX9 21 18:08:02.18 -43:42:52.9 R0 0.5960 14.39 0.59 I RR0 22 18:08:03.74 -43:42:34.5 R0 ---- 10.74 0.17 I L ========================================================= Supplementary Notes CM diagrams published by Alcaino et al. (1997) and by Lee & Carney (2006) show a cluster deficient in RGB stars and an extended blue HB. Fiorentino et al. (2014) subsequently discovered 70 blue straggler stars and detected variabiity in 12 of them. The RA and dec for V1-8 were derived by Samus et al. (2009). The remaining data listed for V2-8 are from Hazen (1994). Hazen noted that the positions of the V3-8 so far from the cluster centre made cluster membership seem unlikely. However, she also showed that they all were located within the tidal radius, which at the time, was considered to be approximately 32 arcminutes, so that firm conclusions about their membership could not be made. Now however, according to the 2010 update of the Harris (1996) catalogue, the estimated tidal radius of NGC 6541 is approximately 13 arcminutes. Thus it is probable that most of these variables belong to the surrounding field. They are listed as field stars. The data for V9-20 are from the discovery paper by Fiorentino et al. (2014). The numbers that they assigned: WU1-3 and SX1-9 are indicated in the remarks column. The data for V21-22 are from the discovery paper by Figuera Jaimes et al. (2016). ====================================================================== Notes on individual stars V1: V1 = SS Cra = Casparie (1960) V10. The period, magnitude, amplitude and classification listed above are from the GCVS (Moscow) and are based on V magnitudes derived by Alcaino (1979) and a period derived by Casparie (1960). V1 was listed as star #127 by Alcaino (1971) and star #42 by Alcaino (1979). V3: Hazen (1994) noted two possible periods for this star: 0.650 or 0.394 days. V5: Hazen (1994) noted that maximum brightness might have been missed. V14: The period listed above is from Figuera Jaimes et al. (2016). The remaining data are from Fiorentino et al. (2014). ================================================================ Discovery of the variable stars in NGC 6541 V1 Woods, reported by Shapley (1922) with 1900 RA and dec. The observed range of mpg was from 12.5 to fainter than 16. V2-8 Hazen (1994) with ID charts, 1950 RA and Dec and x,y coordinates V1 was also included in the ID chart. V9-20 = WUMa1-3, SXP1-9 Fiorentino et al. (2014) with RA and dec V21-22 Figuera Jaimes et al. (2016) ====================================================================== References Alcaino, G. 1971, A&A, 13, 399 Alcaino, G. 1979, A&A Suppl., 35, 233 Alcaino, G., Alvarado, F., Kravtsov, V., Ipatov, A., Samus, N. 1997, AJ, 114, 2638 Casparie, J. P. 1960, Leid. Ann., 21, 377 Figuera Jaimes, R., Bramich, D. M., Skottfelt, J., Kains, N., Jorgensen, U. G., Horne, K., Dominik, M. and 26 coauthors, 2016, A&A, 588, A128 Fiorentino, G., Lanzoni, B., Dalessandro, E., Ferraro, F. R., Bono, G., Marconi, M. 2014, ApJ, 783, 34 Hazen, M. L. 1994, AJ, 107, 1793 Lee, J.-W. & Carney, B. W. 2006, AJ, 132, 2171 Shapley, H. 1922, Harv. Bull., 764, 2 ====================================================================