J/A+A/402/549 NGC 3293 (Baume+, 2003) ================================================================================ Photometric study of the young open cluster NGC 3293 Baume G., Vazquez R.A., Carraro G. and Feinstein A. =2003A&A..402...549 (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Photometry, UBVRIHalpha ; Clusters, open ; Keywords: Galaxy: open clusters and associations: individual: NGC 3293 - Stars: imaging - Stars: luminosity function, mass function Description: Deep and extensive CCD photometric observations at UBV(RI)cHalpha were carried out in the area of the open cluster NGC 3293. The new data set allows to see the entire cluster sequence down to Mv ~ +4.5, revealing that stars with Mv < -2 are evolving off the main sequence; stars with -2 < Mv < +2 are located on the main sequence and stars with Mv > +2 are placed above it. According to our analysis, the cluster distance is d = 2750 \pm 250 pc (Vo-Mv = 12.2 \pm 0.2) and its nuclear age is 8 \pm 1 Myr. NGC 3293 contains an important fraction of pre-main sequence (PMS) stars distributed along a parallel band to the ZAMS with masses from 1 to 2.5 Msun and a mean contraction age of 10 Myr. This last value does not differ too much from the nuclear age estimate. If we take into account the many factors that may affect the PMS star positions on the colour-magnitude diagram, both ages can be perfectly reconciled. The star formation rate, on the other hand, suggests that NGC 3293 stars formed surely in one single event, therefore favouring a coeval process of star formation. Using the Halpha data, we detected nineteen stars with signs of Halpha emission in the region of NGC 3293, another indication that the star formation process is still active in the region. The computed initial mass function for the cluster has a slope of x = 1.2 \pm 0.2, a bit flatter than the typical slope for field stars and similar to the values found for other young open clusters. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- readme.txt 80 . This file table1.txt 150 1690 Photometric catalogue of the NGC 3293 region -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 5 I4 --- Id Identification number (this work) 7- 9 I3 --- Id_T Identification number from TGHH80 11- 13 I3 --- Id_FM Identification number from FM80 15- 17 I3 --- Id_F Identification number from Feast, 1958 19- 21 I3 --- Id_HM Identification number from HM 23- 28 F6.1 pix Xpos X position in pixels (1) 30- 35 F6.1 pix Ypos Y position in pixels (1) 37- 41 F5.2 mag Vmag V magnitude 43- 44 A2 --- com_v Comments for V magnitude (2) 46- 50 F5.2 mag U-B U-B index 52- 53 A2 --- com_ub Comments for U-B index (2) 55- 59 F5.2 mag B-V B-V index 61- 62 A2 --- com_bv Comments for B-V index (2) 64- 68 F5.2 mag V-R V-R index 70- 71 A2 --- com_vr Comments for V-R index (2) 73- 77 F5.2 mag V-I V-I index 79- 80 A2 --- com_vi Comments for V-I index (2) 82- 86 F5.2 mag Ha-Hc Halpha index 88- 89 A2 --- com_ha Comments for Halpha index (2) 91- 93 A3 --- Memb Membership assignment (3) 95-103 A9 --- hd HD identification 105-117 A13 --- cpd CPD identification 120-134 A15 --- tyc Tycho identification 136-150 A15 --- h-i Hipparcos-IRAS identification -------------------------------------------------------------------------------- Note (1): scale = 0.813 arsecond / pixel Note (2): (: ) error larger than 0.05 (::) error larger than 0.10 (FM) data from FM80 (HM) data from HM (TY) data from Tycho catalog Note (3): lm1 = likely member from classical photometric method pm1 = probable member from classical photometric method lm2 = likely member from subtraction method pm2 = probable member from subtraction method nm = non-member -------------------------------------------------------------------------------- References: Feast, MW 1958, MNRAS 118, 618 Feinstein, A, & Marraco, HG 1980, PASP 92, 266 = FM80 Herbst, W & Miller DP 1982, AJ 87, 1478 = HM Turner, DG, Grieve, GR, Herbst, W & Harris WE 1980, AJ 85, 1193 = TGHH80 ================================================================================ (End) G. Baume (2003)