NGC 6366 / C1725-050 (Updated August 2010) RA: 17:27:44.24 DEC: -05:04:47.5 (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 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) "--" or "----" indicates no data available ========================================================================= ID Position Period ampl C Type Notes/ RA/X Dec/Y Units Remarks ========================================================================= 1 17:27:42.69 -05:05:25.2 R0 0.5132 15.8 0.82 V RR0 Note 2 17:28:04.65 -05:11:13.9 R0 ---- 15.022 -- V SR f?;Note 3 -- -- 3.7238 14.29 0.13 V CW? f? 4 -- -- ---- 16.62 -- V L? RGB 5 -- -- ---- 16.31 -- V L? RGB 6 -- -- 0.0802 16.98 0.047 V SXPHE 7 -- -- ---- 17.09 -- V L? RGB 8 -- -- 0.7429 18.70 0.15 V E C8 -- -- 1.1414 16.46 0.03 V EC? C9 -- -- 0.8695 17.69 0.1 V EC? C10 -- -- 0.4317 19.18 0.1 V EC? C11 -- -- 0.5743 18.23 0.05 V EC? ==================================================================== Supplementary Notes and References The RA and dec for V1 and V2 are from Lloyd et al. (2008, Obs 128, 280). All of the data for V3-8 and C8-11 are from Arellano Ferro et al. (2008, Rev. Mex. A&A 44, 365) ============ Notes on individual variables V1: The period, mean magnitude and RR0 classification is from Harris (1993, AJ 106, 604). The V amplitude is from Arellano Ferro et al. (2008) who argued that the star might be a field star, more distant than the cluster. V2: The V magnitude is from Harris (1993) who also derived (B-V) = 2.218. The SR classification is from Lloyd et al. (2008, Obs 128, 280) who analysed the Sawyer Hogg data. They thought it likely that the star lies below the giant branch and therefore might not be a cluster member. V3: Arellano Ferro et al. (2008) noted that this variable could be either a type II Cepheid or an anomalous Cepheid. =================================================================== Discovery of the variable stars in NGC 6366: V1-2 Sawyer (1940, Publ. DDO 1, 179) with x,y positions and ID chart V3-8, C8-11 Arellano Ferro et al. (2008, Rev. Mex. A&A 44, 365) with their positions labelled on an ID chart. These authors also identified candidate variables C1-C7 which they suspected might be long period variables or Cepheids, but the timing of their observations was not suitable for confirming this. ==================================================================== Additional candidate variables Bassa et al. (2008, A&A 488, 921) identified 5 X-ray sources within the half mass radius, based on Chandra data. They concluded that the brightest source CX1 (a point source surrounded by an extended source) is an old nova. They also found optical counterparts in the cluster for CX4 and CX5, which could be magnetically active binaries. The CM diagram of Sarajedini et al. (2007, AJ 133, 1658) shows a large blue straggler (BS) population, but the only BS variable detected so far is the SX Phe star V6 (Arellano Ferro et al. (2008).