NGC 5946 / C1531-504
RA: 15:35:28.52  DEC: -50:39:34.8   (J2000)

(Most recent updates: 
Membership probability flag - 2024; Remaining data - January 2025)
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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
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ID       Position               Mem   Period <mag>  ampl  C Type  Notes/
         RA          Dec        Flag                              Remarks
=========================================================================
1        15:35:48.09 -50:41:24.0 f  ----     --     --      L
2        15:35:23.13 -50:39:50.8 m1 ----     --     --      CST?
3        15:35:37.86 -50:40:08.2 m1   0.70   17.9   1.3   B RR0   
4        15:35:05.83 -50:40:29.7 f  ----     --     --      L
5        15:35:26.00 -50:38:51.1 f  ----     --     --      E?
6        15:35:29.37 -50:41:07.6 f    0.602  18.1   1.3   B RR0  
7        15:35:30.91 -50:39:44.7 m1 ----     --     --      RR?   blend 
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Supplementary Notes 

The RA and dec for the variables are from Samus et al. (2009).  The
remaining data are from Liller (1983) who also presented data for 12
field variables in the cluster vicinity.  

NGC 5946 has not been well studied.  It is a difficult cluster to observe
because it lies near the galactic plane and is heavily reddened.  In the 
2010 update to his catalogue of GC parameters, Harris (1996) lists 
[Fe/H] =-1.29 based on observations by Armandroff & Zinn (1988) and a 
CMD published by Alcaino et al. (1991) shows a predominantly blue HB.  On 
the basis of the giant branch slope, both Alcaino et al. (1991) and 
Davidge (1985) have concluded that the metallicity of this cluster is 
lower than generally assumed.
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Discovery of the variable stars in NGC 5946:

V1-3 = Fourcade #1, 2 and 4
  Fourcade et al. (1966) announced 8 variables in the field of NGC 5946
  and published x,y coordinates and an ID chart.  Sawyer Hogg (1973)
  designated Fourcade's V1, 2 and 4 as V1, 2 and 3 in her 3rd catalogue
  and considered the other 5 to be field variables.

  Since the Fourcade catalogue is not available in many libraries and has 
  not been digitized, many of the stars listed in their catalogue will 
  soon become lost to the literature on globular cluster variable stars.
  For this reason, Layden et al. (2025) published the RA and dec (J2000)
  for the other 5 variables,  #3, #5, #6, #7 and #8. They derived these
  coordinates by matching the stars in Fourcade's charts with modern 
  digital images.  In their paper, Layden et al. also listed a Gaia 
  Source ID for each star.


V4-7 
  Liller (1983) with x,y coordinates and an ID chart
  Liller also announced an additional 7 field variables.

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References

Alcaino, G., Liller, W., Alvarado, F., Wenderoth, E. 1991, AJ, 102, 1371

Armandroff, T. E. & Zinn, R. 1988, AJ, 96,92

Davidge, T. J. 1995, AJ, 110, 1177

Fourcade, C. R., Laborde, J. R., Albarracin, J. 1966, Atlas y Catalogue
de Estrellas Variables en Cumulos Globulares al sur de -29 degrees, Cordoba

Harris, W. E. 1996, AJ, 112, 1487

Layden, A. C., Revangelista, J., Gupta, S., Mittameda, M., Mulloy, E.,
Muslim, S. I., Olushola-Alao, T., Rishi, A. 2025, Astron. Nachr., 346,
Issue 2

Liller, M. 1983, AJ, 88, 404 

Prudil Z., Arellano Ferro, A. 2024, MNRAS, 534, 3654

Sawyer Hogg, H. 1973,  Publ. DDO, 3, No.  6

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