NGC 4833 / C1256-706 (Updated October 2012) RA: 12:59:33.92 DEC: -70:52:35.4 (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 12:58:36.55 -70:44:47.8 R0 0.7501 15.86 1.00 B RR0 Note;RYMus 2 13:00:53.03 -70:57:44.4 R0 333.7 14.6 3.2 P M f;RZMus 3 12:59:33.73 -70:52:13.5 R0 0.7445 15.680 0.440 V RR0 4 12:59:33.82 -70:51:58.1 R0 0.6555 15.560 0.640 V RR0 5 13:00:01.30 -70:53:17.7 R0 0.6294 15.950 1.490 V RR0 6 12:59:56.18 -70:50:10.4 R0 0.6540 15.710 1.320 V RR0 7 12:59:48.79 -70:52:21.4 R0 0.6684 15.770 0.560 V RR0 8 12:58:54.56 -70:44:16.7 R0 ---- -- -- CST Note 9 12:59:25.84 -70:52:30.1 R0 87.7 12.16 -- V SR? 10 12:59:43.24 -70:45:26.1 R0 ---- 13.52 -- V SR? f? 11 12:58:31.42 -71:05:47.2 R0 297.6 15.0 -- V M? f;FQMus 12 12:59:38.31 -70:52:14.4 R0 0.5897 V RR0 13 13:00:29.87 -70:52:56.0 R0 0.3679 16.080 0.650 V RR1 14 12:59:31.06 -70:53:07.2 R0 0.4084 15.640 0.570 V RR1 15 12:59:19.78 -70:53:26.6 R0 0.6673 -- -- V RR0 blend 16 12:59:14.63 -70:49:59.3 R0 ---- 12.59 0.1 V SR? 17 12:59:44.03 -70:54:25.4 R0 0.3904 15.950 0.700 V RR1 18 12:59:28.27 -70:54:25.8 R0 0.4259 16.100 0.600 V RR1 19 12:29:06.02 -70:53:29.7 R0 0.3706 16.100 0.690 V RR1 20 12:59:08.21 -70:52:23.8 R0 0.3002 V RR1 Note;nonrad 21 12:59:50.91 -70:50:36.7 R0 0.3990 15.900 0.600 V RR1 22 12:59:45.11 -70:53:55.8 R0 0.8507 15.900 0.800 V RR0 23 12:59:44.76 -70:51:27.4 R0 0.4070 15.990 0.580 V RR1 24 12:59:36.67 -70:52:59.1 R0 0.6257 V RR0 25 12:58:55.31 -70:51:46.4 R0 0.7230 18.6 -- V EA 26 12:59:02.68 -70:52:52.3 R0 0.3179 15.6 0.16 V RR1 Note;nonrad 27 12:59:13.65 -70:52:10.3 R0 0.0510 -- -- V SXP blend 28 12:59:21.20 -70:53:26.8 R0 0.8740 15.2 0.28 V RR0 29 12:59:35.32 -70:52:41.9 R0 0.0597 -- -- V SXP blend 30 12:59:42.52 -70:53:04.6 R0 0.0443 18.3 0.30 V SXP 31 12:59:47.92 -70:52:52.2 R0 0.0533 -- -- V SXP blend 32 12:59:55.04 -70:52:24.6 R0 0.0707 -- -- V SXP blend 33 12:59:57.66 -70:54:30.6 R0 0.0719 -- -- V SXP blend 34 13:00:25.08 -70:49:16.3 R0 0.3629 16.0 0.15 V EC ==================================================================== Supplementary Notes The coordinates for V1-23 are from Samus et al. (2009) and the ones for V24-34 are from Darragh & Murphy (2012). The periods, magnitudes, amplitudes and classifications for the RR Lyrae, SX Phe and eclipsing variables are from the study by Darragh & Murphy (2012) unless indicated otherwise in the notes. The Mira variables (V2, V11) and the semi-regular variables (V9, V10, V16) were not investigated by Darragh & Murphy because they were too bright or outside their field of view. These five stars are discussed in the notes below. ===================================================================== Notes on individual stars V1: The period is from Wright (1941) and the magnitudes are from Demers & Wehlau (1977). This star was outside the field of Darragh & Murphy's images. Although V1 is located at about 9 arcminutes from the cluster centre, well outside the half-light radius (2.41'), it is inside the tidal radius (17.8') and is a possible cluster member. The P magnitudes published by Wright (1941) and the B magnitudes of Demers & Wehlau (1977) are in the same range as those of the RR Lyrae variables that belong to the cluster. V2, V11: These stars are both classified as Mira variables. Neither is considered to be a cluster member, which is not surprising because because Mira variables are associated with more metal rich populations, i.e. [Fe/H] > -1.0, whereas NGC 4833 has [Fe/H]= -1.85 according to the 2010 revision of the Harris (1996) catalogue. Feast (1966) determined a radial velocity for V2 and demonstrated that it is a field star. The V magnitudes published for V11 by Goossens et al. (1980) are too faint for cluster membership. The period, magnitude and amplitude listed for V2 (RZ Mus) are from Wright (1941). The period and magnitude listed for V11 (FQ Mus) are from Goossens et al. (1980) whose observations indicated that its V amplitude is greater than 2.3 mag. V8: Wright (1941) was unsure of the variability of this star and Demers & Wehlau (1977) concluded that the apparent variability occurred because the star had a close companion. Darragh & Murphy (2012) confirmed that V8 does not vary. V9, V16: These stars are both near the red giant tip and are probably semi-regular variables that are cluster members. The period for V9 was derived by Wright (1941) and the V magnitude by Alcaino (1971). The V magnitude and amplitude for V16 were derived by Menzies (1972). No period has been determined for V16 because the variable was discovered after Wright carried out her study. V10: The V magnitude for V10 is from the photographic study by Demers & Wehlau (1977) who noted that it is a red variable. It was outside the field of view in Menzies' (1972) study, but the Demers & Wehlau magnitudes indicate that it lies redward of the giant branch on Menzies' CM diagram. It is located at about 7 arcminutes from the cluster centre, well outside the half-light radius (2.41'), but inside the tidal radius (17.8') according to the 2010 revision of the Harris (1996) catalogue. Its membership status is uncertain. V20, V26: The periods, magnitudes and amplitudes for these two variables are from Darragh & Murphy (2012). They both appear to be short period RR1 variables that exhibit changes in amplitude due to non-radial oscillations. Olech et al. (2001) identified stars with these properties in several other clusters. ====================================================================== Discovery of the variable stars in NGC 4833: V1-2 discovered by Bailey with RA and dec (epoch 1900) and Harvard variable numbers; announced by Shapley (1923). Their x,y positions were later published by Wright (1941). The numbers V1 and V2 were assigned by Sawyer (1955) in her 2nd catalogue. She also noted that these stars were RY Mus and RZ Mus respectively. V3-11 discovered by various investigators at Harvard and announced by Wright (1941) with x,y coordinates and Harvard variable numbers. The numbers V3-11 were assigned by Sawyer (1955) V12-16 Fourcade et al. (1966) with x,y coordinates and an ID chart V17-24 = B57,B84,B105,B121,B193,C80,C308,D199 on charts published by Menzies (1972) who classified them as possible variables. The numbers V17-24 were assigned by Demers & Wehlau (1977) who published an ID chart for all of V1-24 except V11 (FQ Mus) which was outside of their field of view. V25-34 = NV1-10 Darragh & Murphy (2012) with RA and dec The numbers V25-34 have been assigned in this catalogue. ==================================================================== References Alcaino, G. 1971, A&A, 13, 287 Darragh, A. N. & Murphy, B. W. 2012, J. Southeastern Assoc. Research Ast., 6, 72 Demers, S. & Wehlau, A. 1977, AJ, 82, 620 Feast, M. W. 1966, Obs, 86, 120 Fourcade, C. R., Laborde, J. R., Albarracin, J. 1966, Atlas y Catalogue de Estrellas Variables en Cumulos Globulares al sur de -29 degrees, Cordoba Goossens, M., Stoop, C., Waelkens, C. 1980, IBVS, 1760 Harris, W. E. 1996, AJ, 112, 1487 Menzies, J. 1972, MNRAS, 156, 207 Olech, A., Kaluzny, J., Thompson, I. B., Pych, W., Krzeminski, W., Schwarzenberg-Czerny, A. 2001, MNRAS, 321, 421 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 Shapley, H. 1923, Harv. Bull., 792, 3 Wright, F. W. 1941, Harv. Bull., 792, 3 ====================================================================