J/A+A/417/961 NGC 2580 and NGC 2588 (Baume+, 2004) ================================================================================ NGC 2580 and NGC 2588. Two open clusters in the Third Galactic Quadrant Baume G., Moitinho A., Giorgi E.E., Carraro,G. Vázquez, R.A. =2004A&A...417..961B ================================================================================ ADC_Keywords: Clusters, open ; Photometry, UBVRI Keywords: Galaxy: open clusters and associations: individual: NGC 2580, NGC 2588 - Galaxy: open clusters and associations: general Stars: imaging - Stars: luminosity function, mass function Description: We present CCD broad band photometric observations in the fields of the Third Galactic Quadrant open clusters NGC 2580 and NGC 2588 (V(I)c and UBV(RI)c respectively). From the analysis of our data we found that NGC 2580 is located at a distance of about 4 kpc and its age is close to 160 Myr. As for NGC 2588, it is placed at about 5 kpc from the Sun and is 450 Myr old. This means that NGC 2588 belongs to the extension of the Perseus arm, whereas NGC 2580 is closer to the local arm structure. The luminosity functions (LFs) have been constructed for both clusters down to V ~ 20 together with their initial mass functions (IMFs) for stars with masses above M ~ 1-1.5 Mo. The IMF slopes for the most massive bins yielded values of x ~ 1.3 for NGC 2580 and x ~ 2 for NGC 2588. In the case of this latter cluster we found evidence of a core-corona structure produced probably by dynamical effect. In the main sequences of both clusters we detected gaps, which we suggest could be real features. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- × ReadMe 80 . This file × table3a.dat 114 3171 Photometric catalogue of the NGC 2580 region × table3b.dat 156 4306 Photometric catalogue of the NGC 2588 region -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3a.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 5- 8 I4 --- Seq Identification number (this work) 12- 17 F6.1 pix Xpos X position in arcseconds (1) 21- 26 F6.1 pix Ypos Y position in arcseconds (1) 29- 30 I2 hours RA[h] Right Ascension_2000 [hours] 32- 33 I2 min RA[m] Right Ascension_2000 [minutes] 35- 38 F4.1 sec RA[s] Right Ascension_2000 [seconds] 41- 43 I3 deg Dec[d] Declination_2000 [degrees with sign] 45- 46 I2 min Dec['] Declination_2000 [arcminutes] 48- 51 F4.1 sec Dec[''] Declination_2000 [arcseconds] 56- 60 F5.2 mag Vmag V magnitude 62- 63 A2 --- n_Vmag Comments for V magnitude (2) 68- 72 F5.2 mag V-Ic ? V-Ic colour index 74- 75 A2 --- n_V-Ic Comments for V-Ic index (2) 77- 78 A2 --- Memb Membership assignment (3) 81-114 A34 --- 2MASS/TYC 2MASS and/or TYCHO-2 identification -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3b.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 5- 8 I4 --- Seq Identification number (this work) 12- 17 F6.1 pix Xpos X position in arcseconds (1) 21- 26 F6.1 pix Ypos Y position in arcseconds (1) 29- 30 I2 hours RA[h] Right Ascension_2000 [hours] 32- 33 I2 min RA[m] Right Ascension_2000 [minutes] 35- 38 F4.1 sec RA[s] Right Ascension_2000 [seconds] 41- 43 I3 deg Dec[d] Declination_2000 [degrees with sign] 45- 46 I2 min Dec['] Declination_2000 [arcminutes] 48- 51 F4.1 sec Dec[''] Declination_2000 [arcseconds] 56- 60 F5.2 mag Vmag V magnitude 62- 63 A2 --- n_Vmag Comments for V magnitude (2) 68- 72 F5.2 mag B-V ? B-Vc colour index 74- 75 A2 --- n_B-V Comments for B-Vc index (2) 80- 84 F5.2 mag U-B ? U-Bc colour index 86- 87 A2 --- n_U-B Comments for U-Bc index (2) 92- 96 F5.2 mag V-Rc ? V-Rc colour index 98- 99 A2 --- n_V-Rc Comments for V-Rc index (2) 105-109 F5.2 mag V-Ic ? V-Ic colour index 111-112 A2 --- n_V-Ic Comments for V-Ic index (2) 114-121 A8 --- Memb Membership assignment (3,4) 123-156 A34 --- 2MASS/TYC 2MASS and/or TYCHO-2 identification -------------------------------------------------------------------------------- Note (1): Adopted centers: NGC 2580: RA_2000 = 08:21:28.0; Dec_2000 = -30:18:00.0 NGC 2588: RA_2000 = 08:23:10.0; Dec_2000 = -32:58:30.0 Note (2): Comments on photometry: (: ) error larger than 0.05 (::) error larger than 0.10 Note (3): Membership assignment: lm = likely member pm = probable member nm = non-member Note (4): Additional membership assignment for NGC 2588 pm(red) = probable member in the red clump pm(bin?) = probable member and probable binary star nm(fgr) = nom-member: foreground star ================================================================================ (End) Gustavo L. Baume