NGC 1904 / C0522-245 / Messier 79 RA: 05:24:11.09 DEC: -24:31:29.0 (J2000) (Most recent updates: Membership probability flag - 2024; Remaining data - March 2018) ============================================================ Bytes Format Explanation 1-8 A8 Star ID 10-32 A11,1x,A11 Position 34-35 A2 Membership probability flag based on data published by Prudil & Arellano Ferro (2024) m1: prob >=0.85; m2: prob >=0.7 and <0.85; m3: prob >= 0.5 and <0.7; f: prob <0.5 u: no data available 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 Mem Period ampl C Type Notes/ RA Dec Flag Remarks ========================================================================= 1 05:24:13.00 -24:34:43.8 m1 ---- 15.020 -- V CST Note 2 05:24:16.74 -24:32:34.3 m1 31.3 13.092 0.220 V SR 3 05:24:13.54 -24:32:29.1 m1 0.7361 15.911 0.888 V RR0 4 05:24:17.77 -24:32:16.2 m1 0.6334 16.036 0.999 V RR0 Bl 5 05:24:10.23 -24:31:03.6 m1 0.6689 16.059 0.606 V RR0 Note 6 05:24:06.03 -24:29:32.9 m1 0.3391 16.106 0.481 V RR1 Note 7 05:24:12.68 -24:31:41.9 m1 13.9995 13.644 0.516 V CW Note 8 05:24:11.54 -24:31:38.2 m1 ---- 13.1 1.0 V SR Note 9 05:24:12.58 -24:31:52.6 f 0.3791 16.196 0.423 V RR Note 10 05:24:12.13 -24:31:34.5 m1 0.7289 16.061 0.781 V RR0 11 05:24:11.93 -24:31:34.6 m2 0.8236 -- -- V RR0 12 05:24:11.35 -24:31:28.3 m1 0.3244 16.220 0.531 V RR1 13 05:24:10.59 -24:31:11.5 m1 0.6894 16.265 0.548 V RR0 14 05:24:07.77 -24:31:00.3 m1 0.3237 16.025 0.258 V RR1 15 05:23:23.74 -24:27:46.3 u 0.3091 16.173 0.465 V RR1 16 05:24:09.97 -24:31:07.3 m1 0.0388 18.580 0.433 V SXP 17 05:24:14.15 -24:33:20.7 m1 0.0448 18.687 0.027 V SXP 18 05:24:10.86 -24:31:11.8 m1 0.0503 18.255 0.833 V SXP Note 19 05:24:12.26 -24:31:25.2 m1 ---- -- -- SR? 20 05:23:20.18 -24:28:03.2 u 99.4 13.01 0.63 V SR Note 21 05:24:09.01 -24:31:15.4 m1 29.1 -- -- V SR 22 05:24:09.57 -24:29:51.3 m1 ---- 13.337 0.028 V SR 23 05:24:09.61 -24:30:26.5 m1 ---- 13.216 0.030 V SR 24 05:23:47.33 -24:30:37.5 m1 ---- 13.310 0.074 V SR 25 05:24:40.48 -24:29:00.0 f 21.0 13.783 0.055 V L 26 05:24:18.48 -24:31:43.2 m1 ---- 13.289 0.053 V SR 27 05:24:09.13 -24:34:15.9 m1 ---- 13.059 0.032 V SR 28 05:24:18.04 -24:30:14.7 m1 ---- 13.662 0.028 V SR 29 05:24:21.93 -24:39:03.8 f 0.0604 20.774 0.297 V SXP f 30 05:24:00.02 -24:38:37.6 f 0.1502 19.985 0.205 V SXP? f 31 05:24:57.58 -24:43:17.9 u 0.2938 18.129 0.690 V EW f 32 05:24:18.92 -24:49:39.2 u 0.7587 17.045 0.064 V ? f 33 05:24:31.01 -24:21:38.4 u 23.09 12.113 0.089 V SR? f? 34 05:24:10.86 -24:13:40.1 u 45.3 12.857 0.183 V SR? f PSR -- -- -- -- -- -- R0 ---- -- -- 1 msP ======================================================================= Supplementary Notes The most comprehensive investigation of the variable stars was by Kopacki (2015). The data in the above table are from his study unless indicated otherwise in the notes on individual stars. The field status indicated in the Notes column for V29-34 is based on distance from the cluster centre and/or location in the CM diagram from his study. His paper also included a study of the period-amplitude relation for SX Phe variables known in Galactic globular clusters. Another major study of the variables in NGC 1904 (M79) was by Kains et al. (2012) who carried out a thorough analysis of the RR Lyrae variables. Their results are in good agreement with those of Kopacki (2015). ================================================================== Notes on Individual Stars V1: Rosino (1952) questioned the variability of V1 and its non-variable status was confirmed by Kains et al. (2012) and by Kopacki (2015). The RA and dec listed above are from Kopacki (2015). V5: This is the same star as NV6 of Amigo et a. (2011). According to Samus (2011, private communication), the RA and dec that Samus et al. (2009) published for V5 pertain to a different star. It was difficult to identify the correct variable because of the crowded field on Bailey's (1902) ID chart. V6: Bond et al (2016) showed that the period of V6 fluctuated between 0.339036 and 0.339145 days between 2007 and 2011. This period flucutation is also evident in phase shifts in the light curves published by Amigo et al. (2011) and Kains et al. (2012). The data in the above table are from Kopacki (2015) whose observations were obtained over a time span of 73 days in 2008. V7: Kopacki (2015) showed that V7 was a type II Cepheid and derived a period of 13.985 days based on their 73-day span of observations. Bond et al. (2016) derived a period of 13.9995 days based on more than 4 years of observations. Their period is listed in the above table and the remaining data are from Kopacki (2015). V8: Bond et al. (2016) plotted B and V light curves with observations that spanned more than 1500 days between February 2007 and May 2011. These curves clearly demonstrated that V8 is a semiregular variable with a maximum V amplitude of approximately 1 mag and periods ranging from 65 to 80 days. The data for V8 in the above table are from Bond's study. V9: This is a multiperiodic star. Kopacki (2015) carried out a detailed analysis and concluded that the secondary periods correspond to non-radial modes of pulsation. Kains et al. (2012) had previously suggested that V9 might be a double-mode RR Lyrae, pulsating simultaneously in the first overtone and fundamental modes. V15: With r = 11.4 arcmin from the cluster centre, V15 is outside the tidal radius (8 arcmin). However, Kopacki (2015) concluded that it is a cluster member because of its position on the horizontal branch of the CM diagram. This is a reasonable assumption because Carballo-Bello et al. (2018) have found that an important fraction of cluster stars are probably located well beyond the tidal radius. V18: According to Kopacki (2015), V18 is pulsating simultaneously in the radial fundamental and first overtone modes. V20 = ASAS 052320-2428.1 The period, mean V magnitude and amplitude are from Pojmanski (2002). With r = 12.1 arcmin from the cluster centre, V20 is well outside the tidal radius. However, its location at the red giant tip on the CM diagram is appropriate for a semi-regular variable that is a cluster member. See note for V15. ================================================================= Discovery of the variable stars in M79: V1-5 Bailey (1902) with x,y coordinates (page 238) and an ID chart (plate X, Fig 2, page 252.19) V6 Rosino (1952) with x,y coordinates and an ID chart for V1-6 (The ID chart appeared in the Bologna Pub version of his paper, but not in the electronic edition of Memoirs of the Italian Astronomical Society.) Rosino made small corrections to the y coordinates published by Bailey for V3 and V4 and commented that his V3 was too faint to be detected on the print published by Bailey (1902). V7-8 Tsoo Yu-hua (reported to Sawyer Hogg in a 1965 letter) In her 3rd catalogue, Sawyer Hogg (1973) assigned the numbers V7-8 and published their x,y coordinates. V9-13 = NV1-5 Amigo et al. (2011) with RA and dec V14 Kains et al. (2012) with RA, dec and ID charts Variables V2-14 are all labelled on their ID chart. V14 was independently discovered by Kopacki & Pigulski (2012) who called it n15. V15-34 Kopacki (2015) with ID charts and RA & dec V15 was previously announced as n14 and V16-18 as n16-18 by Kopacki & Pigulski (2012) The tidal radius of M79 is 8 arcmin. V29-34 are close to the tidal radius or beyond and unlikely to be cluster members. PSR: According to Paulo Freire's website at the Max Planck Institute in Bonn (July 2024 version), there is one millisecond pulsar in NGC 1904 (M79) ----------------------------------------------------------- Bond et al (2016) discovered a luminous F-type post-asymptotic- giant-branch star with V=12.20 and (V-I)=0.46 mag at RA: 5:24:10.36, dec: -24:29:20.6. Its radial velocity indicates cluster membership, but no variability was detected. In their paper, they published B and V light curves for V6, V7, V8, V13 and V14. ================================================================ References Amigo, P., Catelan, M., Stetson, P. B., Smith, H. A., Cacciari, C., Zoccali, M. 2011, in Carnegie Obs. Astrophys. Series, Vol. 5: RR Lyrae Stars, Metal-Poor Stars, and the Galaxy, ed. A. McWilliam Bailey, S. I. 1902, Harvard Annals, Vol 38 Bond, H. E., Ciardullo, R., Siegel, M. H. 2016, AJ, 151, 40 Carballo-Bello, J. A., Martinez-Delgado, D., Navarette, C., Catelan, M., Munoz, R. R., Antoja, T., Sollima, A. 2018, MNRAS, 474, 683 Kains, N., Bramich, D. M., Figuera Jaimes, R., Arellano Ferro, A., Giridhar, S., Kuppuswamy, K. 2012, A&A, 548, A92 Kopacki, G. 2015, Acta A., 65, 81 Kopacki, G. & Pigulski, A. 2012, arXiv:1211.5463 Pojmanski, G. 2002, Acta A. 52, 397 Prudil Z., Arellano Ferro, A. 2024, MNRAS, 534, 3654 Rosino, L. 1952, Bologna Pub, 5, No. 20 = Mem Soc Ast It, 23, 101 Samus, N. N., Kazarovets, E. V., Pastukhova, E. N., Tsvetkova, T. M., Durlevich, O. V. 2009, PASP, 121, 1378 ===================================================================