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J/AJ/128/2316       BVRIJHKs photometry in sigma Ori cluster     (Sherry+, 2004)

Photometric identification of the low-mass population of Orion OB1b. I. The σ Orionis cluster. Sherry W.H., Walter F.M., Wolk S.J. <Astron. J., 128, 2316-2330 (2004)> =2004AJ....128.2316S
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, UBVRIJKLMNH Keywords: open clusters and associations: individual (sigma Orionis) - stars: formation - stars: imaging - stars: low-mass, brown dwarfs - stars: pre-main-sequence Abstract: We report an optical photometric survey of 0.89deg2 of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest-density region within Orion OB1b. We have developed a statistical procedure to identify the young, low-mass, pre-main-sequence population of the association. We estimate that the cluster has 160 members in the mass range (0.2M≤M≤1.0M). The cluster has a radius of 35pc and an estimated age of 2.5±0.3Myr. We estimate that the total mass of the cluster is 225±30M. This mass is similar to the estimated mass of the ∼5x105yr old cluster NGC 2024. NGC 2024 and sigma Ori appear to be a well-matched pair of clusters, except for the ∼2Myr difference in their ages. Description: In this paper we analyze data from observations made with the 0.9 and 1.5m telescopes at the Cerro Tololo Inter-American Observatory (CTIO) between 1996 and 2002 as part of a B, V, RC, and IC survey of the belt of Orion (Orion OB1b) File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 63 58 Adopted Color-Temperature Relation for ∼3Myr Old Stars table4.dat 111 234 Photometry of Likely Cluster Members
See also: J/A+A/429/1007 : RIJHK photometry of VLM objects near eps Ori (Scholz+, 2005) J/A+A/419/249 : RJHKs photometry of sigma Ori low-mass stars (Scholz+, 2004) J/AN/325/705 : RIJHKs of low-mass stars in sigma Ori (Bejar+, 2004) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 2 A2 --- SpType MK spectral type (1) 4- 8 I5 K Teff Effective temperature (2) 10- 14 F5.2 mag BC Bolometric correction 16- 20 F5.2 mag U-V ? The (U-V) color index 22- 26 F5.2 mag B-V ? The (B-V) color index 28- 32 F5.2 mag V-Rc ? The (V-RC) color index 34- 38 F5.2 mag V-Ic The (V-IC) color index 40- 44 F5.2 mag V-J The (V-J) color index 46- 50 F5.2 mag V-H The (V-H) color index 52- 56 F5.2 mag V-K The (V-K) color index 58- 62 F5.2 mag V-L The (V-L) color index
Note (1): Colors and bolometric correction for stars earlier than M7 were taken from Kenyon & Hartmann (1995, Cat. J/ApJS/101/117>). For stars later than M7 we used U-V, B-V, and V-Rc from Berriman et al. (1992ApJ...392L..31B) and V-Ic, V-J, V-H, V-K, V-L and bolometric corrections from Leggett et al. (2001ApJ...548..908L). Note (2): Teff for M stars are from Luhman (1999ApJ...525..466L).
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 2 I2 h RAh Hour of right ascension (J2000) (1) 4- 5 I2 min RAm Minute of right ascension (J2000) (1) 7- 12 F6.3 s RAs Second of right ascension (J2000) (1) 14 A1 --- DE- Sign of the declination (J2000) (1) 15- 16 I2 deg DEd Degree of declination (J2000) (1) (1) 18- 19 I2 arcmin DEm Arcminute of declination (J2000) 21- 25 F5.2 arcsec DEs Arcsecond of declination (J2000) (1) 27- 31 F5.2 mag Bmag ? The B-band magnitude 33- 36 F4.2 mag e_Bmag ? Error in Bmag 38- 42 F5.2 mag Vmag The V-band magnitude 44- 47 F4.2 mag e_Vmag Error in Vmag 49- 53 F5.2 mag Rcmag The RC band magnitude 55- 58 F4.2 mag e_Rcmag Error in Rmag 60- 64 F5.2 mag Icmag The IC band magnitude 66- 69 F4.2 mag e_Icmag Error in Imag 71- 75 F5.2 mag Jmag ? 2MASS J-band magnitude (2) 77- 80 F4.2 mag e_Jmag ? Error in Jmag 82- 86 F5.2 mag Hmag ? 2MASS H-band magnitude (2) 88- 91 F4.2 mag e_Hmag ? Error in Hmag 93- 97 F5.2 mag Ksmag ? 2MASS Ks-band magnitude (2) 99-102 F4.2 mag e_Ksmag ? Error in Ksmag 104-105 I2 % Prob Membership probability 107-110 F4.2 solMass Mass Estimated mass (3)
Note (1): Objects are identified as [SWW2004] JHHMMSS.sss+DDMMSS.ss in Simbad Note (2): Available at http://iras.ipac.caltech.edu/ Note (3): Masses were estimated from the observed V-IC using a 2.5Myr isochrone.
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 23-Aug-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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