NGC 6304 / C1711-294 (Updated April 2013) RA: 17:14:32.25 DEC: -29:27:43.3 (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 17:14:40.47 -29:29:34.3 R0 0.4723 17.000 0.81 V RR0 f 2 17:14:18.69 -29:24:58.6 R0 0.3989 16.586 1.21 V RR0 f 3 17:14:47.57 -29:26:33.5 R0 0.8555 16.731 0.65 V RR0 mem? 4 17:14:11.58 -29:30:32.1 R0 0.8122 15.968 0.58 V AC mem?;Note 5 17:14:49.51 -29:27:40.9 R0 0.2145 -- -- RR? HBH 6 17:14:56.40 -29:30:38.8 R0 ---- -- -- CST 7 17:14:33.35 -29:32:28.0 R0 0.5758 17.237 0.63 V RR0 f 8 17:15:09.74 -29:26:30.5 R0 0.6079 -- -- RR0 HBH 9 17:15:16.91 -29:23:23.7 R0 0.3489 -- -- RR1 HBH 10 17:13:47.25 -29:32:18.9 R0 0.6283 16.729 0.78 V RR0 11 17:14:14.97 -29:36:53.9 R0 ---- -- -- L f 12 17:14:19.26 -29:19:42.2 R0 ---- -- -- L f 13 17:14:20.61 -29:23:41.3 R0 ---- -- -- CST 14 17:14:23.14 -29:36:41.7 R0 ---- -- -- L Note 15 17:14:33.23 -29:25:48.4 R0 ---- -- -- CST? 16 17:14:41.79 -29:25:37.4 R0 ---- -- -- L f 17 17:14:58.27 -29:30:42.7 R0 ---- -- -- CST? 18 17:15:09.51 -29:27:36.1 R0 ---- -- -- L f 19 17:14:44.62 -29:35:45.4 R0 ---- -- -- CST? 20 17:14:46.71 -29:36:45.5 R0 ---- -- -- CST? 21 17:15:10.19 -29:26:18.0 R0 ---- -- -- CST? 22 17:14:37.67 -29:27:31.1 R0 0.3380 16.289 0.39 V RR1 mem 23 17:14:27.33 -29:27:40.2 R0 0.3939 16.816 0.34 V RR1 mem? 24 17:14:48.89 -29:32:00.7 R0 0.3698 16.656 0.45 V RR1 mem? ================================================================== Supplementary Notes The cluster NGC 6304 is a metal rich cluster located in a rich field in the galactic bulge. The first investigations of variable stars were by Rosino (1962) and Terzan (1966, 1968), but no periods were derived by either of these authors. A later study of the variables in NGC 6304 and the surrounding field was by Hartwick et al. (1981). They derived periods for the 40 RR Lyrae stars in their field and identified a number of other suspected variables, many of which they classified as long period variables. It is generally assumed that most of the variables belong to the field around NGC 6304 and not to the cluster itself. De Lee et al. (2006) carried out a new study of the RR Lyrae variables to investigate the possibility that some of them might be cluster members in light of the discovery of long period RR Lyrae variables in the metal rich clusters NGC 6388 and NGC 6441. They estimated the membership status based on distance from the cluster, mean magnitude and reddening. The membership status listed for the RR Lyrae variables is based on their study. For RR Lyrae stars with V magnitudes listed in the above table, the periods, magnitudes and amplitudes are from the OGLE III catalogue (Sosyzynski et al. 2011). The periods, classifications and membership status for V5-6, V8-9 and V11-21 are from Hartwick et al. (1981). The RA and dec in the above table for V1-21 are from Samus et al. (2009) and for V22-24 from (Sosyzynski et al. 2011). ===================================================================== Notes on individual stars V4: De Lee et al. (2006) pointed out that this star might be an anomalous Cepheid because its light curve does not have the characteristic shape expected for an RR Lyrae with a such a long period. V14: This star might be a cluster member. The magnitudes published by Hartwock et al. (1981) are in the appropriate range for cluster membership. ================================================================== Discovery of the variable stars in NGC 6304: V1-11 Rosino (1962) with x,y coordinates and an ID chart Some of these variables are also in the OGLE III catalogue (Sosyzynski et al. 2011). V1, 2, 3, 4, 7, 10 are OGLE-BLG-RRLYR 00247, 00232, 00253, 00225, 00242, 00201 respectively. V12-18 = #28, 29, 30, 32, 33, 40, 43 Terzan (1966) with an ID chart The numbers V12-18 were assigned by Sawyer Hogg (1973) in her 3rd catalogue. Terzan announced 58 (V1-58) variables in his paper, but Sawyer Hogg assigned numbers only to the ones that were located within approximately 15 arcminutes of the cluster centre. The 2010 revision of the Harris (1996) catalogue inicates a tidal radius of 13.25 arcminutes for NGC 6304. V19-21 = #68, 69, 72 Terzan (1968) with an ID chart The numbers V19-21 were assigned by Sawyer Hogg (1973) in her 3rd catalogue. Terzan announced 25 new variables (V59-83) in his paper, but Sawyer Hogg assigned numbers only to the ones within 15 arcminutes of the cluster centre. V22-23 = #1247 & #4209, suspected variables Hesser & Hartwick (1976) with ID chart Their variability was later confirmed by De Lee et al. (2006). Both stars are included in the OGLE III catalogue of RR Lyrae variables as OGLE-BLG-RRLYR 00246 and 00237 respectively The numbers V22 and V23 have been assigned in this on-line (Sosyzynski et al. 2011). catalogue. V24 = NV1 De Lee et al. (2006) with no ID or coordinates However, based on the period they derived, this star appears to be OGLE-BLG-RRLYR-00255 (Sosyzynski et al. 2011). The number V24 has been assigned in this on-line catalogue. De Lee et al. included a few other 'new' RR Lyrae variables in their investigation, but they did not consider any of them to be possible cluster members. Therefore they are not listed in the above table. These stars were listed as HBH67, Va46, NV2 which are the same stars as OGLE-BLG-RRLYR-00256,-00251 and -00238 respectively (Sosyzynski et al. 2011). =================================================================== References de Lee, N., Catelan, M., Layden, A., Pritzl, B., Smith, H., Sweigart, A., Welch, D. 2006, Mem SAI, 77, 117 Harris, W. E. 1996, AJ, 112, 1487 Hesser, J. E. & Hartwick, F. D. A. 1976, ApJ, 203, 113 Rosino, L. 1962, Mem SAI, 33, 351 = Asiago-Padova Cont. 132 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Sawyer Hogg, H. 1973, Publ. DDO, 3, No. 6 Sosyzynski, I., Dziembowski, W. A., Udalski, A., Poleski, R., Szymanski, M. K., Kubiak, M., Pietrzynski, G., Wyrzkowski, L., Ulaczyk, K., Kozlowski, S., Pietrukowicz, P. 2011, AcA, 61, 1 Terzan, A. 1966, POHP, 9, 1 Terzan, A. 1968, POHP, 9, 24 ========================================================================