NGC 7099 / C2137-234 / Messier 30 (Updated September 2014) RA: 21:40:22.12 DEC: -23:10:47.5 (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 21:40:24.25 -23:11:46.8 R0 0.7436 15.12 0.93 V RR0 2 21:40:26.44 -23:12:51.5 R0 0.6535 15.20 0.92 V RR0 3 21:40:15.04 -23:11:28.2 R0 0.6963 15.12 0.94 V RR0 4 21:39:58.44 -23:11:43.1 R0 ---- 16.5 2.8 V UG max;f;Note 5 21:40:16.20 -23:08:44.8 R0 ---- 17.42 -- V CST? 6 21:40:19.22 -23:10:44.4 R0 ---- 15.34 -- V CST? 7 21:40:18.68 -23:08:54.3 R0 ---- 16.63 -- V CST? 8 21:40:21.25 -23:11:17.8 R0 ---- 15.00 -- V CST? 9 21:40:21.72 -23:11:09.4 R0 ---- 15.40 -- V CST? 10 21:40:21.93 -23:11:24.3 R0 ---- 15.44 -- V CST? 11 21:40:25.64 -23:10:08.3 R0 ---- 16.11 -- V CST? 12 21:40:27.88 -23:12:07.7 R0 ---- 15.49 -- V CST? 13 21:40:21.09 -23:11:32.9 R0 ---- 15.69 -- V CST? 14 21:40:21.10 -23:11:30.8 R0 0.3480 15.18 0.48 V RR1 15 21:40:21.79 -23:10:50.1 R0 0.6790 15.07 1.08 V RR0 16 21:40:24.81 -23:11:48.8 R0 0.3254 15.22 0.33 V RR1 17 21:40:23.66 -23:11:01.1 R0 0.0600 14.14 0.07 V SXP blend? 18 21:40:21.88 -23:09:32.4 R0 0.3071 17.43 0.41 V E 19 21:40:22.09 -23:10:43.3 R0 0.3434 13.85 0.15 V RR1 f 20 21:40:29.83 -23:11:05.9 R0 0.0402 17.79 0.15 V SXP 21 21:40:47.80 -23:10:23.9 R0 0.1132 17.87 0.2 V ? 22 21:40:22.02 -23:10:46.7 R0 0.284 17.90 0.27 V EW max 23 21:40:22.21 -23:10:48.3 R0 0.3175 17.28 0.28 V EW max 24 21:40:22.51 -23:10:54.4 R0 0.211 19.54 0.54 V EW max 25 21:40:22.28 -23:10:40.6 R0 0.2149 20.06 0.75 V EW max 26 21:40:22.51 -23:10:50.9 R0 0.386 19.72 0.33 V Ell max =================================================================== Supplementary Notes The RA and dec listed for V1-13 are from Samus et al. (2009) and those for V14-21 are from Kains et al. (2013). The remaining data are from the study by Kains et al. (2013) unless indicated otherwise in the notes. All of the data for V22-26 are from the discovery paper by Pietrukowicz & Kaluzny (2004). They are their M30_04 to M30_08, respectively. ======================================================================= Notes on individual stars V4: Rosino (1961) commented that V4 was unlikely to be a cluster member and this conclusion was later confirmed by Machin et al. (1991) based on the radial velocity they derived. It is considered to be a foreground star. Pietrukowicz et al (2008) pointed out that V4 has a likely X-ray counterpart. These latter authors easily recovered the variable and plotted a light curve. The magnitudes listed in the above table were read from their light curve. Kains et al. (2013) made extensive observations of V4 and derived a period of 2.22 hours from their quiescent phase data. ================================================================= Discovery of the variable stars in M30: V1-3 Bailey (1902) with x,y coordinates (page 244) and an ID chart (plate XII, Fig. 4, page 252.23) V4 Rosino (1949) with an ID chart for V1-4. The x,y coordinates for V4 were later derived by Sawyer (1955) for her 2nd catalogue and a finding chart was published by Kains et al. (2013). V4 is NSV 25717 in the Moscow GCVS (Samus et al.) V5-12 (=Terzan's V1-8) Terzan (1968) with an ID chart He classified these new variables as short period Cepheids. The numbers V5-V12 were assigned by Sawyer Hogg (1973) in her 3rd catalogue. Their x,y coordinates were later published by Terzan & Rutily (1975). V13 Terzan & Rutily (1975) with ID chart and x,y coordinates. They also published x,y coordinates for V5-V12 and included V6, V8, V9 and V10 on their ID chart. Kains et al. (2013) were unable to confirm the variability of any of these stars and from the ID chart, it appears that most of them have unresolved companions. V14-21 Kains et al. (2013) with RA, dec and finding charts for all of the confirmed variables in the cluster. V22-26 = M30_04 - M30_08 Pietrukowicz & Kaluzny (2004) with RA, dec, and X,Y pixel positions from HST archival data. They also independently discovered V15 and V19 (their M30_02 and M30_03 respectively). ------------------------------------------------------------------------ Possible CVs and active binaries in the cluster Lugger et al. (2007) obtained Chandra observations of M30 and identified 50 X-ray sources in the vicinity of the cluster, six of which were located within 12 arcsec of the cluster centre. They used Hubble archival images to make optical identifications of the centrally located sources and concluded that their source A1 might be a qLMXB and that sources A2, A3, B, and C might be CVs. They published RA, dec and finding charts for all of these objects. They also detected the possible X-ray counterpart of the pulsar M30A identified by Ransom et al. (2004). Pietrukowicz et al. (2008 - see page 1116) checked their V data for variability of stars near these sources and found none. Pietrukowicz (2009) estimated that there should be about 40 CVs in the dense core of M30, but these are difficult to detect with ground based telescopes. In an attempt to identify CVs among the X-ray sources in the outer regions of the cluster, they made H_alpha observations with a ground based telescope (SOAR). They detected one source that is a likely CV and one that they considered to be an AB (chromospherically and magnetically active binary). In their search for CVs in globular clusters, Pietrukowicz et al. (2008) noted that they would not have been able to recover CVs in the small and crowded cluster core. ----------------------------------------------------------------------- Ransom et al. (2004) discovered two binary millisecond pulsars, M30A (11ms) and M30B (13ms) using the Green Bank Telescope. ====================================================================== References Bailey, S. I. 1902, Harv. Ann., 38 Kains, N., Bramich, D. M., Arellano Ferro, A., Figuera Jaimes, R., Jorgensen, U. G., Giridhar, S., Penny, M. T., and 43 coauthors, 2013, A&A, 555, A36 Lugger, P. M., Cohn, H. N., Heinke, C. O., Grindlay, J. E., Edmonds, P. D. 2007, ApJ, 657, 286 Machin, G., Callanan, P. J., Allington-Smith, J., Charles, P. A., Hassall, B. J. M. 1991, MNRAS, 250, 602 Pietrukowicz, P. 2009, Acta A., 59, 291 Pietrukowicz, P. & Kaluzny, J. 2004, Acta A., 54, 19 Pietrukowicz, P., Kaluzny, J., Schwarzenberg-Czerny, A., Thompson, I. B., Pych, W., Krzeminski, W., Mazur, B. 2008, MNRAS, 388, 1111 Ransom, S. M., Stairs, I. H., Backer, D. C., Greenhill, L. J., Bassa, C. G., Hessels, J. W. T., Kaspi, V. M. 2004, ApJ, 604, 328 Rosino, L. 1949, Mem. S. A. I., 20, 63 = Bologna Publ., V, No.9 Rosino, L. 1961, Asiago-Padova Cont., 117 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Sawyer, H. B. 1955, Publ. DDO, 2, No. 2 Sawyer Hogg, H. 1973, Publ. DDO, 3, No. 6 Terzan, A. 1968, Haute-Provence Publ., 9, No. 24 Terzan, A. & Rutily, B. 1975, A&A, 38, 307 ======================================================================