NGC 6528 / C1801-300
RA: 18:04:49.64  DEC: -30:03:22.6   (J2000)

(Most recent updates: 
Membership probability flag - 2024; Remaining data - January 2015)
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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        18:04:49.38 -30:03:27.2 f    0.2559 15.61  0.19  I RR1 
2        18:04:49.36 -30:03:19.5 f  ----     16.18  0.14  I RR0?  Note
3        18:04:49.51 -30:03:26.7 f  128.37   12.399 0.154 I SR    Ogle  
4        18:04:49.61 -30:03:38.2 m1  46.13   12.419 0.044 I SR?   Ogle
5        18:04:50.01 -30:03:20.9 f  ----     12.70  0.10  I L 
6        18:04:49.09 -30:03:17.6 f  ----     12.66  0.06  I L 
7        18:04:49.36 -30:03:28.5 m2 ----     19.6   --    I E?
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Supplementary Notes 

NGC 6528 is a metal rich cluster that is located in a rich field in the
Galactic bulge.  Harris (1996) lists [Fe/H] = -0.11 in the 2010 update 
to his catalogue.  
A CM diagram by Lagoia et al. (2014) shows a prominent red HB.  

The data in the above table are from Skottfelt et al. (2015) unless 
indicated "Ogle" in the Remarks column.  For the Ogle stars, the 
period, magnitude, amplitude and classification are from Soszynski 
et al. (2013).

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Notes on individual stars

V2:  Skottfelt et al. (2015) derived a tentative period of 0.8165 for
     this star, but noted that the light curve was "noisy".
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Discovery of the variable stars in NGC 6528:

  V1-7
    Skottfelt et al. (2015) with RA, dec and a finding chart

    V3 and V4 (Ogle #13921 and #13923 respectively) were 
    independently discovered by Soszynski et al. (2013) in the 
    Ogle III investigation of long period variables in the Galactic
    Bulge.
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References

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

Lagoia, E. P., Milone, A. P., Bono, G., Stetson, P. B., Prada Moroni, P.
G., Dall'Ora, M., Aparicio, A. and 8 coauthors, 2014, ApJ, 782, 50

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

Skottfelt, J., Bramich, D. M., Figuera Jaimes, R., Jorgensen, U. G.,
Kains, N., Arellano Ferro, A., Alsubai, K. A. and 27 coauthors, 2015, 
A&A, 573, A103

Soszynski, I., Udalksi, A., Szymanski, M. K., Kubiak, M., Pietrzynski,
G., Wyrzykowski, L., Ulaczyk, K. and 3 coauthors,  2013, Acta A., 63, 21

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