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 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 159 53 Photometric and spectroscopic parameters for
53 Sigma Orionis candidates
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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
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Bytes Format Units Label Explanations
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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
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Note (1): Notes have the following meaning:
* = IAU name from Bejar et al., 1999ApJ...521..671B 1999ApJ...521..671B
** = IAU name from Bejar et al., 2001ApJ...556..830B 2001ApJ...556..830B
a = Spectroscopic data from Zapatero Osorio et al.,
2002A&A...384..937Z 2002A&A...384..937Z. All these objects have Li.
b = Haro 5-36, from Haro, 1953BOTT....1g..11H 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 1991PASJ...43...27W
e = Spectroscopic data from Barrado y Navascues et al.,
2003A&A...404..171B 2003A&A...404..171B
f = Spectroscopic data from Bejar 2000, PhD. at Universidad de La Laguna
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Acknowledgements: Victor J.S. Bejar, vbejar(at)iac.es
(End) Victor J.S. Bejar [IAC, Spain], Patricia Vannier [CDS] 06-May-2005