NGC 6656 / C1833-239 / Messier 22 (Updated 2009) RA: 18:36:24.2 DEC: -23:54:12 (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 or P (for photographic). 61-65 A5 Type of variable (draft 2006 GCVS classifications) NV denotes not variable 67-80 A19 Notes and Remarks (f denotes field star; mem indicates cluster membership) "--" or "----" indicates no data available ========================================================================= ID Position Period ampl C Type Notes/ RA/X Dec/Y Units Remarks ========================================================================= 1 18:33:16.50 -23:57:04.0 R5 0.6155 15.0 1.3 P RR0 2 18:33:32.16 -23:55:39.6 R5 0.6417 14.0 0.7 P RR0 3 18:33:35.20 -23:49:47.0 R5 0.5156 16.0 0.6 P RR0 4 18:33:20.30 -23:58:01.0 R5 0.7164 14.65 0.9 P RR0 5 18:33:07.52 -23:57:30.4 R5 93.1 12.85 0.7 B SR mem 6 18:33:15.12 -23:58:34.3 R5 0.6385 14.25 0.7 P RR0 7 18:32:54.80 -23:50:11.0 R5 0.6495 14.55 1.4 P RR0 8 18:33:17.69 -23:57:58.6 R5 61.0 12.66 0.7 B SR mem 9 18:33:05.12 -23:57:32.4 R5 87.7 13.14 0.5 B SR? mem 10 18:33:17.80 -23:58:58.0 R5 0.6460 14.3 0.95 P RR0 11 18:33:19.70 -23:56:41.0 R5 1.6905 13.55 0.5 P CW 12 18:33:20.70 -23:58:11.0 R5 ---- -- -- NV? Note 13 18:33:25.66 -23:54:11.4 R5 0.6725 14.4 1.0 P RR0 14 18:33:37.60 -23:48:40.0 R5 200.0 16.0 3.8 B M f?;Note 15 18:33:29.04 -23:58:12.3 R5 0.3732 14.6 0.5 P RR1 16 18:33:34.00 -23:57:05.0 R5 0.3256 14.55 0.5 P RR1 17 18:32:48.00 -23:54:52.0 R5 113.3 15.85 1.4 B SR f?;Note 18 18:33:13.30 -23:49:46.0 R5 0.3249 14.6 0.6 P RR1 19 18:33:17.59 -23:54:48.8 R5 0.3840 14.6 0.4 P RR1 20 18:33:11.70 -23:59:03.0 R5 0.4301 14.25 0.5 P RR1 21 18:33:22.80 -23:55:30.0 R5 0.3274 14.4 0.6 P RR1 22 18:32:00.40 -23:53:41.0 R5 0.6245 15.15 1.5 P RR0 23 18:33:20.00 -23:57:13.0 R5 0.5508 14.45 0.9 P RR0 24 18:33:21.00 -23:57:01.0 R5 ---- 14.5 0.6 P RR 25 18:33:43.40 -23:50:35.0 R5 0.4024 14.6 0.4 P RR1 26 18:32:20.20 -23:49:22.0 R5 309.0 16.45 2.0 B f? 27 18:32:25.40 -23:47:57.0 R5 0.3428 14.45 0.5 P RR1 28 18:31:49.07 -23:55:20.6 R5 424.0 14.25 1.0 B f?;Note 29 18:33:27.80 -23:43:35.0 R5 0.3043 14.78 0.45 P RR1 30 18:33:37.94 -24:00:51.5 R5 82.5 13.1 1.0 B SR mem?;Note 31 18:33:06.80 -24:08:19.2 R5 95.0 13.4 1.2 B SR mem?;Note 32 18:32:34.00 -24:02:23.0 R5 233.5 16.5 2.6 B f? 33 18:33:10.70 -24:10:23.0 R5 251.1 15.8 2.7 B f? 34 18:33:22.98 -23:58:03.7 R5 ---- -- -- Lb: red 35 18:33:21.00 -23:57:01.0 R5 ---- -- -- Lb: red 36 18:32:36.10 -23:56:32.0 R5 ---- 17.25 1.1 B mem? 37 18:32:46.00 -23:43:27.0 R5 ---- 16.05 0.9 V mem? 38 18:32:46.40 -23:45:12.0 R5 ---- 16.30 1.0 B mem? 39 18:33:06.60 -24:02:05.0 R5 ---- 16.20 0.6 V mem? 40 18:33:32.00 -23:49:55.0 R5 ---- 16.75 0.5 B mem? 41 18:33:56.00 -23:55:23.0 R5 ---- 17.15 0.5 V mem? 42 18:33:56.70 -23:49:50.0 R5 ---- 17.15 0.5 V mem? 43 18:33:56.90 -23:54:54.0 R5 ---- 16.65 0.5 V mem? KT-01 18:36:43.34 -23:56:24.9 R0 ---- 18.64 0.14 V EW max KT-02 18:36:41.82 -23:56:20.3 R0 ---- 17.35 0.25 V EB max KT-03 18:36:41.27 -23:52:19.2 R0 ---- 18.64 0.22 V EW max KT-04 18:36:39.38 -23:52:25.1 R0 0.0360 16.82 0.14 V SXPHE KT-05 18:36:39.09 -23:50:27.3 R0 0.0610 17.24 0.22 V SXPHE KT-07 18:36:36.85 -23:56:59.9 R0 ---- 17.96 0.05 V EW max KT-08 18:36:35.68 -23:55:14.6 R0 ---- 19.9 0.6 V EW max;Note KT-10 18:36:32.30 -23:54:27.2 R0 0.0370 16.63 0.06 V SXPHE KT-12 18:36:30.95 -23:53:48.3 R0 16.18 0.62 V RR max;f;Note KT-13 18:36:30.86 -23:53:45.6 R0 0.2817 17.54 0.38 V EW max KT-14 18:36:30.67 -23:53:53.1 R0 ---- 13.93 0.22 V RR max;Note KT-15 18:36:30.13 -23:49:58.7 R0 ---- 16.40 0.60 V EW max KT-16 18:36:30.37 -23:57:12.3 R0 ---- 14.11 0.06 V RR max;Note KT-18 18:36:29.04 -23:49:58.8 R0 ---- 17.95 0.50 V EA max;Note KT-20 18:36:26.09 -23:51:26.4 R0 ---- 16.58 0.16 V EW max KT-23 18:36:23.84 -23:51:15.8 R0 ---- 16.46 0.20 V EW max KT-26 18:36:23.17 -23:53:22.7 R0 ---- 14.06 0.12 V RR max;Note KT-27 18:36:22.54 -23:55:12.4 R0 0.0422 16.99 0.11 V SXPHE KT-28 18:36:22.04 -23:52:05.9 R0 0.0550 16.22 0.06 V SXPHE KT-29 18:36:20.97 -23:55:47.5 R0 0.0450 16.70 0.16 V SXPHE KT-33 18:36:16.86 -23:53:54.5 R0 ---- 16.95 0.06 V EW max KT-34 18:36:16.90 -23:55:24.3 R0 0.0470 16.83 0.09 V SXPHE KT-36 18:36:15.90 -23:56:06.3 R0 ---- 13.99 0.34 V RR max KT-37 18:36:13.19 -23:53:46.3 R0 ---- 14.10 0.12 V RR max;Note KT-38 18:36:11.45 -23:56:46.8 R0 0.0330 16.91 0.05 V SXPHE KT-39 18:36:10.00 -23:51:57.3 R0 ---- 17.23 0.17 V EW max KT-40 18:36:08.14 -23:51:48.5 R0 ---- 17.74 0.0 V EW max KT-41 18:36:07.10 -23:54:12.6 R0 ---- 17.70 0.52 V EW max KT-42 18:36:34.67 -23:52:30.5 R0 ---- 17.35 0.07 V DSCT? max,f? KT-43 18:36:24.27 -23:56:18.9 R0 0.2205 18.42 0.42 V EW max KT-45 18:36:22.04 -23:54:41.0 R0 0.0500 16.71 0.24 V SXPHE KT-46 18:36:21.78 -23:58:24.3 R0 ---- 19.50 1.00 V EB max KT-48 18:36:16.55 -23:57:35.7 R0 ---- 19.95 0.50 V E? max KT-51 18:36:35.08 -23:53:03.6 R0 ---- 14.60 0.04 V E? max KT-54 18:36:24.95 -23:50:49.7 R0 0.0800 16.37 0.07 V SXPHE KT-55 18:36:23.25 -23:53:57.3 R0 ---- 13.87 0.15 V RR max;Note PK-04 18:36:22.79 -23:52:48.3 R0 0.3123 18.46 0.32 I EW max PK-05 18:36:22.26 -23:54:32.9 R0 0.2428 17.25 0.19 I EW max PK-06 18:36:25.19 -23:54:37.3 R0 0.2394 17.14 0.47 I EW max PK-07 18:36:26.89 -23:53:43.3 R0 0.3557 17.87 0.11 I BY? max PK-08 18:36:24.17 -23:54.10.1 R0 0.3273 18.70 0.20 I BY? max PK-09 18:36:29.99 -23:55:42.8 R0 1.4791 17.93 0.16 I BY? max PK-10 18:36:27.12 -23:52:59.7 R0 5.2500 17.32 0.32 I BY? max PK-11 18:36:30.32 -23:55:23.0 R0 0.0662 19.85 0.16 I ELL? max CV1 18:36:24.66 -23:54:35.5 R0 ---- -- -- UG? CV2 18:36:02.72 -23:55:24.6 R0 ---- -- -- UG mem? P1 18:36:22.40 -23:56:29.4 R0 ---- -- -- =================================================================== Supplementary Notes and References The positions listed above for V1-43 are from Kravtsov et al. (1994, Ast Letters 20, 339). These authors also listed GCVS numbers for V14, V17, V22, V26, V28, V31, V32 and V33. They are Sgr variables V1311, V4068, V3853, V2007, V2367, V3855, V4067, and V4069 respectively. V29 and V30 are NSV 11080 and 11084. ID charts for V1-35 were published by Wehlau & Sawyer Hogg (1977, AJ 82, 137) and (1978, AJ 83, 946). The 'outer' variables are shown in the first paper and the 'inner' variables in the second. The periods, magnitudes, amplitudes, variabiity type and membership status listed for these variables are from these two papers unless otherwise noted. The RR Lyrae and Cepheid were discussed in their 1978 AJ paper and the red variables were discussed in their 1977 AJ paper. For all of the remaining variables, the positions and other data are taken from the discovery papers unless indicated otherwise in the notes. ================ Notes on individual stars V12: According to Sawyer (1944, DDO Publ 1, No. 15), Bailey doubted the variability of V12. She also found that its variability was not confirmed on her plates. Wehlau & Sawyer Hogg (1978, AJ 83, 946) measured V12 on many of their plates but the data were not good enough to confirm variability. However, Kravtsov et al. (1994, Ast Letters 20, 339) questioned the non-variable status of V12. V14, V17, V28: The variability type listed for these stars is from Marinchev (1983, Per Zve 22, 65) V30-31: The periods, magnitudes, amplitudes and variability types are from Marinchev (1983, Per Zve 22, 65) and membership status from Wehlau & Sawyer Hogg (1977, AJ 82). KT-08, KT-12, KT-14,, KT-16, KT-18; KT-26, KT-37, KT-55: The mean magnitude and amplitude for these stars are uncertain because Kaluzny &Thompson's (2001, A&A 373, 899) maximum magnitude is a lower limit and/or their minimum magnitude is an upper limit. KT-13, KT-27 and KT-43 The magnitudes, amplitudes and variability types for these 3 stars are from Kaluzny & Thompson (2001, A&A, 373, 899). Their periods are from Pietrukowicz & Kaluzny (2003, AcA 53, 371) who listed them as #2, #1 and #3, respectively. ======================================================================== Discovery of the variable stars in M22: V1-16 Bailey, H.A. 38 (1902) with ID chart V17 by Swope and announced by Shapley, Harv Bulletin 848 (1927) with x,y positions for V1-17 V18-25 Sawyer, DDO Publ, 1, no. 15 (1944) with x,y positions for V1-25 and ID chart for V1-21 and V23-25. (V22 was outside the field.) V26-31 = #181a,181b,173a,187b,191,185 by Hoffleit, IBVS 660 (1972) with 1900 RA & dec and later identified on a chart by Wehlau & Sawyer Hogg (1977 AJ 82, 137) V32&33 V. Sherwood, an assistant to Sawyer Hogg (unpublished) & identified on the chart by Wehlau & Sawyer Hogg (1977, AJ 82) V34&35 Lloyd Evans (1978, MNRAS 182, 293) reported (see page 300) that Kukarkin had discovered two red variables not previously known. These were star IV-17 labelled on a plate by Arp & Melbourne (1959, AJ 64, 28) and star V-9 labelled by Lloyd Evans (1975, MNRAS 171, 647). Wehlau & Sawyer Hogg (1978, AJ 83, 946) numbered these two variables as V34 and V35 respectively and identified them on their ID chart. Both stars are near the red giant tip. V36-43 Kravtsov et al. Astronomy Letters 20, 339 (1994) with ID chart and RA & dec. They noted that these are faint for RR Lyrae cluster members, but they could be members if they are subgiants. KT-01 to KT-55 (CASE M22 variables) Kaluzny & Thompson, A&A, 373, p.899, (2001) with RA & dec These authors intially selected 55 candidate variables, but only 36 of them turned out to be new variables: 6 were spurious and 13 were RR Lyrae variables that were already known. PK-04 to PK-11 Pietrukowicz & Kaluzny, AcA 53, 371 (2003) with RA & dec P&K also listed data for three stars numbered 1 to 3 which the same stars as KT-27, 13 and 43 respectively. CV1 Anderson et al. (2003, ApJL 597, L137) with RA, dec and ID chart CV2 Pietrukowicz et al. (2005, ActaAst 55, 261) with RA, dec and ID chart. Webb et al., A&A 424, 133 (2004) announced that there are 5 (+/-3) X-ray sources associated with M22 and Pietrukowicz believe that CV2 is associated with one of them. P1 is a probable microlensing event detected by Pietrukowicz et al. (2005, ActaAst 55, 261) who listed the RA & dec and published an ID chart. ==========================================================