NGC 6101 / C1620-720 (Updated February 2013) RA: 16:25:48.12 DEC: -72:12:07.9 (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 16:26:02.7 -72:11:14.3 R0 0.4583 16.381 0.379 V RR1 2 16:26:01.7 -72:13:30.4 R0 0.4116 16.440 0.443 V RR1 3 16:26:12.3 -72:13:00.0 R0 0.7545 16.640 0.722 V RR0 4 16:26:15.8 -72:11:53.5 R0 0.3490 16.520 0.535 V RR1 5 16:26:29.2 -72:09:51.6 R0 0.4259 16.453 0.466 V RR1 Note 6 16:25:50.4 -72:11:10.1 R0 0.3462 16.373 0.525 V RR1 Note 7 16:25:19.7 -72:10:50.8 R0 0.4101 16.640 0.461 V RR1 8 16:26:22.7 -72:11:28.5 R0 0.4152 16.532 0.453 V RR1 9 16:25:48.3 -72:11:24.8 R0 0.3402 16.686 0.426 V RR1 10 16:25:30.3 -72:12:48.5 R0 0.3486 16.608 0.468 V RR1 11 16:28:11.17 -71:57:43.4 R0 ---- 17.20 1.08 B RR? f;Note 12 16:23:56.17 -72:19:56.5 R0 ---- 18.13 1.26 B L f;Note 13 16:23:16.33 -72:24:43.2 R0 ---- 15.28 1.46 B CW? f;Note 14 16:23:43.49 -72:07:56.1 R0 ---- 15.86 0.67 B CW? f;Note 15 16:25:40.09 -72:23:11.1 R0 ---- 15.61 0.56 B CW? f;Note 16 16:24:45.7 -72:15:02.7 R0 0.380 16.462 0.478 V RR1 17 16:25:04.9 -72:07:11.2 R0 0.417 16.224 0.192 V RR1 18 16:25:27.6 -72:16:13.8 R0 0.427 16.397 0.421 V RR1 19 16:25:34.0 -72:08:58.8 R0 0.372 16.536 0.341 V RR1 20 16:26:05.8 -72:12:12.8 R0 0.9144 16.254 0.643 V RR0 21 16:26:57.3 -72:08:50.5 R0 0.320 16.486 0.226 V RR1 22 16:25:17.1 -72:11:41.3 R0 0.3191 16.505 0.100 V RR1 23 16:26:01.62 -72:12:29.8 R0 ---- 16.48 -- V ? E?/L? =========================================================================== Supplementary Notes The most comprehensive studies of the RR Lyrae in NGC 6101 were by Cohen et al. (2011) and Fitzgerald et al. (2012). The Cohen observations were obtained on 6 consecutive nights in July 2008 and the Fitzgerald observations were made on 31 nights between June 2010 and April 2011. The variables V1-10, V20, V22 were studied by both groups and for these stars, we adopt the periods derived by Fitzgerald et al. and the RA, dec, magnitudes and amplitudes from Cohen et al. All the data for V16-19 and V21 are from Cohen et al. (2011) and the data for V23 are from Fitzgerald et al. (2012). The RA and dec for V11-15 are from Samus et al. (2009) and the remaining data for these stars are from the discovery paper by Liller (1981) Sarajedini & Da Costa (1999) showed that NGC 6101 has a significant blue straggler population, but no variable star searches have yet been undertaken among the BSS population. ======================================================================= Notes on individual stars V5, V6: Fitzgerald et al. (2012) derived periods that were significantly different from the ones derived by Cohen et al. Cohen's periods did not fit Fitzgerald's observations, but Fitzgerald's periods (our adopted periods) gave a satisfactory fit to Cohen's observations. V11-15: These variables are considered to be field stars. They are all located more than 10 arcmin from the cluster centre, well beyond the tidal radius (which is 6.1 arcmin, according to the 2010 edition of Harris's catalogue). The tidal radius had not been derived at the time of the Liller (1981) study. V12-15 are NSV 20592, 20587, 20591, 20604 in the Moscow GCVS. ======================================================================= Discovery of the variable stars in NGC 6101: V1-15 Liller (1981) with x,y coordinates and an ID chart Fourcade et al. (1966) had previously observed the cluster but did not discover any variables. V16-22 Cohen et al. (2011) with RA, dec and and an ID chart V23 Fitzgerald et al. (2012) with RA, dec and an ID chart ========================================================================== References Cohen, R. E., Sarajedini, A., Kinemuchi, K., Leiton, R. 2011, ApJ, 727, 9 Fitzgerald, M. T., Criss, J., Lukaszewicz, T., Frew, D. J., Catelan, M., Woodward, S., Danaia, L., McKinnon, D. H. 2012, PASA, 29, 72 Fourcade, C. R., Laborde, J. R., Albarracin, J. 1966, Atlas y Catalogue de Estrellas Variables en Cumulos Globulares al sur de -29 degrees, Cordoba Liller, M. H. 1981, AJ, 86, 1204 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Sarajedini, A. & Da Costa, G. S. 1991, AJ, 102, 628 =====================================================================