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J/AJ/117/2868      BV photometry in M2 (NGC 7089)       (Lee+, 1999)

BV photometry of RR Lyrae variables in the globular cluster M2 (NGC 7089). Lee J.-W., Carney B.W. <Astron. J. 117, 2868 (1999)> =1999AJ....117.2868L
ADC_Keywords: Stars, variable ; Photometry, CCD ; Photometry, UBV Keywords: globular clusters: individual (NGC 7089) - RR Lyrae variable - stars: horizontal-branch Abstract: We present BV CCD photometry for 30 RR Lyrae variables, including 13 newly discovered, in the Oosterhoff type II globular cluster M2. New light curves and ephemerides are presented. Our observations cover magnitudes ranging from the red giant branch tip to ∼3mag below the turnoff, allowing us to determine accurate fundamental photometric parameters. With the discovery of new RR Lyrae variables, the mean periods of the RRab and RRc variables are <Pab≥0.685±0.022days and <Pc≥0.333±0.013days, respectively. The number ratio of the RRc type variables to the total number of RR Lyrae type variables is n(c)/n(ab+c)=0.40. The RR Lyrae pulsational mode transition occurs between the fundamental period of 0.528-days and 0.556-days. From star counts along the horizontal branch (HB), we obtain two HB color distribution indices, (B-R)/(B+V+R)=0.92 and B2/(B+V+R)=0.46. The period-change rates are also derived. The mean period-change rate from six RRab variables is <β≥0.06±0.04days/Myr, which agrees well with the predictions of Lee's 1991 model. Our color-magnitude diagram shows a very extended blue HB tail, and there are no significant blue HB gaps in M2. Objects: ---------------------------------------------------------- RA (2000) DE Designation(s) ---------------------------------------------------------- 21 33 29.3 -00 49 23 M 2 = NGC 7089 ---------------------------------------------------------- File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 37 19229 Color-magnitude diagram data table3.dat 75 30 Parameters for M2 RR Lyrae variables table4.dat 54 4200 RR Lyrae data
See also: V/97 : Updated 3rd Cat Variable Stars in Globular Clusters (Clement+ 1997) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 5 I5 --- LC Identification number (Cl* NGC 7089 LC NNNNN in Simbad) 7- 14 F8.3 pix Xpos X position (1) 16- 23 F8.3 pix Ypos Y position (1) 25- 30 F6.3 mag B-V B-V colour index 32- 37 F6.3 mag Vmag V magnitude
Note (1): 1pix=0.68". Plate centered on the cluster (RA=21h33min, DE=-0°49', J2000.0)
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Name RR Lyrae name (G1) 9- 17 F9.7 d Per Period 19- 32 F14.6 d Ep0 Epoch at φ=0.00 34- 38 F5.3 mag AV Absorption in V band 40- 44 F5.3 mag AB Absorption in B band 46- 51 F6.3 mag <Vmag> Magnitude-weighted integrated V magnitude 53- 58 F6.3 mag <Bmag> Magnitude-weighted integrated B magnitude 60- 65 F6.3 mag <Vint> Intensity-weighted integrated V magnitude 67- 72 F6.3 mag <Bint> Intensity-weighted integrated B magnitude 74- 75 A2 --- Class [ab c] RR Lyrae class
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 7 A7 --- Name RR Lyrae name (G1) 9- 24 F16.8 d HJD Heliocentric Julian date 26- 31 F6.4 --- Phase [0/1] Phase 33- 39 F7.4 mag Vmag V magnitude 41- 46 F6.4 mag B-V B-V colour index 48- 54 F7.4 mag Bmag B magnitude
Global notes: Note (G1): VNN = Cl* NGC 7089 SAW VNNN in Simbad LCNNNN = Cl* NGC 7089 LC NNNNN in Simbad
History: From AJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 14-Sep-1999
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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