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J/AN/325/705  RIJHKs of low-mass stars in sigma Ori        (Bejar+, 2004)

Optical and infrared photometry of new very low-mass stars and brown dwarfs in the sigma Orionis cluster. Bejar V.J.S., Zapatero Osorio M.R., Rebolo R. <Astron. Nachrichten, 325, 705-713 (2004)> =2004AN....325..705B
ADC_Keywords: Clusters, open ; Stars, pre-main sequence; Stars, late-type ; Photometry, CCD ; Photometry, infrared ; Photometry, UBVRI Keywords: stars: low-mass, brown dwarfs - stars: luminosity function, mass function - stars: colour--magnitude diagrams (H-R diagrams) - stars: formation - stars: open clusters and associations - stars: individual (sigma Orionis) Abstract: We present an RI photometric survey covering an area of 430 arcmin2 around the multiple star sigma Orionis. The observations were conducted with the 0.8m IAC-80 Telescope at the Teide Observatory. The survey limiting R and I magnitudes are 22.5 and 21, and completeness magnitudes 21 and 20, respectively. We have selected 53 candidates from the I vs. R-I colour-magnitude diagram (I=14-20) that follow the previously known photometric sequence of the cluster. Adopting an age of 2-4 Myr for the cluster, we find that these objects span a mass range from 0.35M to 0.015M. We have performed J-band photometry of 52 candidates and K_s photometry for 12 of them, with the result that 50 follow the expected infrared sequence for the cluster, thus confirming with great confidence that the majority of the candidates are bona fide members. JHK_s photometry from the Two Micron All Sky Survey (2MASS, Cat. II/246) is available for 50 of the candidates and are in good agreement with our data. Out of 48 candidates, which have photometric accuracies better than 0.1mag in all bands, only three appear to show near-infrared excesses. Description: Photometric and spectroscopic parameters for sigma Ori very low-mass stars and brown dwarfs candidates. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 159 53 Photometric and spectroscopic parameters for 53 Sigma Orionis candidates
See also: II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) J/A+A/419/249 : RJHKs photometry of sigma Ori low-mass stars (Scholz+, 2004) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 22 A22 --- [BMZ2001] IAU Name (S Ori JHHMMSS.s+DDMMSS) 23- 27 A5 --- n_[BMZ2001] Note on [BMZ2001] (1) 28- 35 A8 --- OName Name of previous identified objects 37- 38 I2 --- ChartID Finder chart identification number in article 40- 44 F5.2 mag Imag Johnson I magnitude 46- 49 F4.2 mag e_Imag I magnitude error 51- 54 F4.2 mag R-I Johnson R-I colour index 56- 59 F4.2 mag e_R-I R-I colour error 61- 65 F5.2 mag Jmag ? Johnson J magnitude 67- 70 F4.2 mag e_Jmag ? J magnitude error 72- 75 F4.2 mag I-J ? Johnson I-J colour index 77- 80 F4.2 mag e_I-J ? I-J colour error 82- 85 F4.2 mag I-Ks ? I-Ks colour index 87- 90 F4.2 mag e_I-Ks ? I-Ks colour error 92- 95 F4.2 mag I-J2 ? I-J colour index (J from 2MASS) 97-100 F4.2 mag e_I-J2 ? I-J2 colour error (J from 2MASS) 102-105 F4.2 mag J-H ? J-H colour index (2MASS photometry) 107-110 F4.2 mag e_J-H ? J-H colour error (2MASS photometry) 112-115 F4.2 mag H-Ks ? H-Ks colour index (2MASS photometry) 117-120 F4.2 mag e_H-Ks ? H-Ks colour error (2MASS photometry) 122-125 A4 --- SpType MK Spectral Type 127-131 F5.2 mag E(R-I) ? R-I colour excess 133-136 F4.2 mag e_E(R-I) ? R-I colour excess error 138 I1 h RAh Right ascension (J2000.0) 140-141 I2 min RAm Right ascension (J2000.0) 143-146 F4.1 s RAs Right ascension (J2000.0) 148 A1 --- DE- Declination sign (J2000.0) 149 I1 deg DEd Declination (J2000.0) 151-152 I2 arcmin DEm Declination (J2000.0) 154-155 I2 arcsec DEs Declination (J2000.0) 157-159 A3 --- pnm [pnm] pnm: probably not member
Note (1): Notes have the following meaning: * = IAU name from Bejar et al., 1999ApJ...521..671B ** = IAU name from Bejar et al., 2001ApJ...556..830B a = Spectroscopic data from Zapatero Osorio et al., 2002A&A...384..937Z. All these objects have Li. b = Haro 5-36, from Haro, 1953BOTT....1g..11H c = X-ray source from Wolk 1996, Ph. D. University of New York at Stony Brook d = Kiso A-0976 329 from Wiramihardja et al., 1991PASJ...43...27W e = Spectroscopic data from Barrado y Navascues et al., 2003A&A...404..171B f = Spectroscopic data from Bejar 2000, PhD. at Universidad de La Laguna
Acknowledgements: Victor J.S. Bejar, vbejar(at)
(End) Victor J.S. Bejar [IAC, Spain], Patricia Vannier [CDS] 06-May-2005
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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