NGC 6139 / C1624-387 (updated July 2024) RA: 16:27:40.37 DEC: -38:50:55.5 (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) 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 16:28:11.77 -38:40:04.6 R0 150.000 15.4 0.8 V SR f;Note 2 16:27:12.54 -38:49:29.0 R0 79.87 14.647 1.04 V SR 3 16:28:27.94 -38:54:39.2 R0 269.00 15.2 2.4 V M f;Note 4 16:28:08.40 -38:48:46.9 R0 ---- -- -- UG? Note 5 16:27:34.31 -38:51:19.3 R0 0.5950 17.777 0.893 V RR0 6 16:27:43.79 -38:48:21.7 R0 0.7059 17.975 0.592 V RR0 7 16:27:44.54 -38:47:59.5 R0 0.4206 17.901 0.372 V RR1 8 16:28:16.40 -38:49:58.8 R0 0.3532 18.065 0.724 V E f 9 16:27:35.40 -38:41:26.8 R0 0.526 18.85 1.5 B RR0 f;Note 10 16:27:26.31 -38:49:07.3 R0 0.7582 18.015 0.613 V RR0 11 16:27:38.32 -38:53:10.6 R0 0.3188 17.920 0.453 V RR1 12 16:27:37.56 -38:52:07.5 R0 0.3473 17.823 0.453 V RR1 13 16:27:40.02 -38:50:56.9 R0 189.0588 14.873 0.482 V SR 14 16:27:40.56 -38:51:05.0 R0 ---- 14.705 0.482 V SR 15 16:27:42.24 -38:50:59.8 R0 0.3649 17.819 0.214 V RR1? Note 16 16:27:35.56 -38:51:42.6 R0 0.3215 17.719 0.228 V RR1 17 16:27:32.88 -38:50:42.2 R0 27.5010 15.196 0.134 V SR 18 16:27:41.77 -38:50:33.0 R0 85.1571 15.725 0.254 V SR ========================================================================== Supplementary Notes NGC 6139 is a moderately metal poor, heavily reddened cluster near the Galactic bulge. According to the 2010 update to the Harris (1996) catalogue, it has a core radius of 0.15 arcminutes, a 0.85 arcminute half-light radius, a tidal radius of 10.9 arcminutes, and [Fe/H] = -1.65. The first search for variable stars in NGC 6139 was conducted by Hazen (1991). A more recent investigation was carried out by Yepez et al. (2023). In the above table, the data are from the following sources: V1-10: The RA and dec are from Samus et al. (2009). The remaining data for V2, V5, V6, V7, V8 and V10 are from Yepez et al. (2023). V1, V3, V4 and V9 were ouside their field of view. The sources for these stars are indicated in the notes on individual stars. V11-18: All of the data are from the paper by Yepez et al. (2023). =========================================================================== Notes on individual stars V1: This star was included in the AAVSO VSX database and the period, magnitude, amplitude and classification are from that source. The star's "field" status was determined by Bustos Fierro & Calderson (2019) based on Gaia D2 data. V3: This star was also included in the AAVSO VSX data base and the period, magnitude, amplitude and classification are from thag source. The star's "field" status was determined by Bustos Fierro & Calderson (2019) based on Gaia D2 data. V4: Hazen (1991) classified V4 as a possible cataclysmic variable. However, she observed only one outburst in her data and the minimum was well below the plate limits (Bmag > 19.6). She therefore noted that further work was required to determine the true nature of the star's variability. V4 was included in the AAVSO VSX utility (Watson et al. 2006) and they listed a magnitude range of B = 16.8 to 22.1 mag. The membership status of V4 is unknown. V9: The period, B magnitude and amplitude and classification are from the discovery paper by Hazen (1991). The star's "field" status was determined by Bustos Fierro & Calderson (2019) based on Gaia D2 data. V15: Yepez et al. (2023) tentatively classified this star as an RR1 variable. However, they pointed out that, in the CM diagram, it is located to the red of the HB, on the red giant branch. =========================================================================== Discovery of the variable stars in NGC 6139: V1-10 Hazen (1991) with x,y coordinates and ID charts Hazen also provided data for 6 field variables, F1-6, which she discovered outside the cluster's tidal radius which was assumed to be 12.6 arcminutes at that time. Fourcade et al. (1966) had previously observed the cluster but did not discover any variables. V11-18 Yepez et al. (2023) announced these variables and published RA, dec (J2000) and identification charts. Their study included 20 new variables in the field of NGC 6139. Some had been previously reported by the Gaia Collaboration (2016, 2023) and the others were discovered from their own observations which were obtained with telescopes in Argentina and Chile. The numbers V11-V18 were assigned by Yepez et al. (2023). These are the stars that they considered to be cluster members based on astrometric data availble in Gaia-D3. The other 12 were assumed to be field stars and are not included in the above table. ======================================================================== References Bustos Fierro, I. H., Calderson, J. H. 2019, MNRAS, 488, 3024 Fourcade, C. R., Laborde, J. R., Albarracin, J. 1966, Atlas y Catalogue de Estrellas Variables en Cumulos Globulares al sur de -29 degrees, Cordoba Gaia Collaboration, 2016, A&A, 595, A1 Gaia Collaboration, 2023, A&A, 674, A1 Hazen, M. L. 1991, AJ, 101, 170 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 Watson, C. L., Henden, A. A., Price, A. 2006, Soc. for Ast. Sci. Symp., 25, 47 Yepez, M. A., Arellano Ferro, A,., Bustos Fierro, I., Luna, A. 2023, 524, 1503 =======================================================================