J/A+A/402/549       UBVRIHalpha photometry of NGC 3293       (Baume+, 2003)

Photometric study of the young open cluster NGC 3293. Baume G., Vazquez R.A., Carraro G., Feinstein A. <Astron. Astrophys. 402, 549 (2003)> =2003A&A...402..549B 2003A&A...402..549B
ADC_Keywords: Clusters, open ; Photometry, UBVRI ; Photometry, H-alpha 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)cHα 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±250pc (V0-Mv=12.2±0.2) and its nuclear age is 8±1Myr. 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 2.5M and a mean contraction age of 10Myr. 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±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 80 . This file table1.dat 150 1690 Photometric catalogue of the NGC 3293 region -------------------------------------------------------------------------------- Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 5 I4 --- Seq Identification number (this work) 7- 9 I3 --- TGHH80 [3/133]? Identification number from Turner et al., 1980AJ.....85.1193T 1980AJ.....85.1193T (1) 12- 13 I2 --- FM80 [2/58]? Identification number from Feinstein & Marraco, 1980PASP...92..266F 1980PASP...92..266F (2) 16- 17 I2 --- FEAS [2/43]? Identification number from Feast, 1958MNRAS.118..618F 1958MNRAS.118..618F (1) 19- 21 I3 --- HM [9/541]? Identification number from Herbst & Miller, 1982AJ.....87.1478H 1982AJ.....87.1478H (1) 23- 28 F6.1 pix Xpos X position in pixels (3) 30- 35 F6.1 pix Ypos Y position in pixels (3) 37- 41 F5.2 mag Vmag V magnitude 43- 44 A2 --- n_Vmag Comments for V magnitude (4) 46- 50 F5.2 mag U-B ? U-B colour index 52- 53 A2 --- n_U-B Comments for U-B index (4) 55- 59 F5.2 mag B-V ? B-V colour index 61- 62 A2 --- n_B-V Comments for B-V index (4) 64- 68 F5.2 mag V-Rc ? V-Rc colour index 70- 71 A2 --- n_V-Rc Comments for V-Rc index (4) 73- 77 F5.2 mag V-Ic ? V-Ic colour index 79- 80 A2 --- n_V-Ic Comments for V-Ic index (4) 82- 86 F5.2 mag Halpha ? Halpha index 88- 89 A2 --- n_Halpha Comments for Halpha index (4) 91- 93 A3 --- Memb Membership assignment (5) 95-103 A9 --- HD HD III/135 identification 105-117 A13 --- CPD CPD I/108 identification 120-122 A3 --- --- [TYC] 123-134 A12 --- TYC Tycho I/239 identification 136-150 A15 --- Other Hipparcos or IRAS identification -------------------------------------------------------------------------------- Note (1): For numbers lower than 500, identified as Cl* NGC 3293 FEAS NNN in Simbad. For numbers upper than 500 (HM numbers only), WEBDA numbers. Note (2): Indetified as Cl* NGC 3293 FM NN Note (3): Scale = 0.813 arsecond / pixel Note (4): Comments on photometry: (: ) error larger than 0.05 (::) error larger than 0.10 (FM) data from Feinstein & Marraco, 1980PASP...92..266F 1980PASP...92..266F (HM) data from Herbst & Miller, 1982AJ.....87.1478H 1982AJ.....87.1478H (TY) data from Tycho catalog, Cat. I/239 Note (5): Membership assignment: 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 -------------------------------------------------------------------------------- Acknowledgements: Gustavo Baume
(End) Patricia Bauer [CDS] 23-Sep-2003
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