J/MNRAS/355/475 Markarian 50 (Baume+, 2004) ================================================================================ The young open cluster Markarian 50 Baume G., Vazquez R.A., Carraro G. =2004MNRAS...355..475B ================================================================================ ADC_Keywords: Clusters, open ; Photometry, UBVRI Keywords: stars: imaging - stars: individual: HD 219460 stars: individual: WR 157 - stars:luminosity function, mass function stars: Wolf-Rayet open clusters and associations:individual:Markarian 50 Abstract: We report on a deep CCD UBV(RI)c photometric survey in the region of the young open cluster Markarian 50. The new photometric data allow us to extend the cluster membership down to V ~ 17.5, about 2 mag deeper than any previous investigation. On the basis of these data we derive a distance d = 3460 +- 350 pc (Vo-Mv = 12.7 +- 0.2), which turns out to be only a bit lower than previous estimates. The cluster presents differential reddening, with E(B-V) values ranging from 0.69 to 1.1. The brightest member (HD 219460) is a double star which we separate photometrically for the first time, providing individual magnitudes and colors for each component. One of them is a WR star and according to evolutionary models, the mass of its progenitor should be greater than ~ 20 Mo. The age obtained for the cluster is 7.5 +- 2 Myr and the mass function for the most massive stars (M > 1 Mo) presents a slope x ~ 1.0. Description: Our data set comes from CCD photometric observations carried out using the AFOSC camera attached to the 1.82 m Copernico telescope of Cima Ekar (Asiago, Italy) File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- × ReadMe 80 . This file × table3.dat 177 1097 Photometric catalogue of the Mark 50 region -------------------------------------------------------------------------------- See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) I/259 : The Tycho-2 Catalogue (Hog+ 2000) Byte-by-byte Description of file: table3.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 5 I4 --- Seq Identification number (this work) 7- 10 I4 --- Tid Identification number (Turner+ 1983) 12- 17 F6.1 arcsec Xpos X position (1) 19- 24 F6.1 arcsec Ypos Y position (1) 27- 28 I2 h RAh Right Ascension (2000) 30- 31 I2 min RAm Right Ascension (2000) 33- 36 F4.1 s RAs Right Ascension (2000) 39- 40 I2 deg DEd Declination (2000) 42- 43 I2 arcmin DEm Declination (2000) 45- 48 F4.1 arcsec DEs Declination (2000) 51- 55 F5.2 mag Vmag V magnitude 57- 58 A2 --- u_Vmag Comments for V magnitude (2) 60- 64 F5.2 mag B-V ? B-Vc colour index 66- 67 A2 --- u_B-V Comments for B-V index (2) 69- 73 F5.2 mag U-B ? U-Bc colour index 75- 76 A2 --- u_U-B Comments for U-B index (2) 78- 82 F5.2 mag V-Rc ? V-Rc colour index 84- 85 A2 --- u_V-Rc Comments for V-Rc index (2) 87- 91 F5.2 mag V-Ic ? V-Ic colour index 93- 94 A2 --- u_V-Ic Comments for V-Ic index (2) 96-100 F5.2 mag E(B-V) B-V excess 103-107 F5.2 mag E(U-B) U-B excess 110-114 F5.2 mag E(V-R) V-R excess 117-121 F5.2 mag E(V-I) V-I excess 123-130 A8 --- SC Spectral Classification (3) 132-133 A2 --- Memb Membership assignment (4) 135-144 A10 --- OtherID HD, ALS and/or BD identification 146-160 A15 --- TYC TYCHO-2 identification (TYC FFFF-NNNNN-N) 162-177 A16 --- 2MASS 2MASS designation (JHHMMSSss-DDMMSS) -------------------------------------------------------------------------------- Note (1): Adopted center for Markarian 50: RA_2000 = 23:15:14.5; DEC_2000 = +60:26:30.0 Note (2): Comments on photometry: (: ) error larger than 0.05 (::) error larger than 0.10 Note (3): Spectral classification from Turner+ (1983) and Massey+ (2001) Note (4): Membership assignment lm = likely member pm = probable member nm = non-member -------------------------------------------------------------------------------- ================================================================================ (End) Gustavo Baume