J/ApJ/662/1067 Spitzer observations of sigma Orionis (Hernandez+, 2007)
A Spitzer Space Telescope study of disks in the young σ Orionis cluster.
Hernandez J., Hartmann L., Megeath T., Gutermuth R., Muzerolle J.,
Calvet N., Vivas A.K., Briceno C., Allen L., Stauffer J., Young E.,
Fazio G.
<Astrophys. J., 662, 1067-1081 (2007)>
=2007ApJ...662.1067H 2007ApJ...662.1067H
ADC_Keywords: Clusters, open ; Infrared sources ; Photometry, infrared
Keywords: infrared: stars -
open clusters and associations: individual (sigma Orionis cluster) -
planetary systems: protoplanetary disks - stars: formation -
stars: pre-main sequence
Abstract:
We report new Spitzer Space Telescope observations, using the IRAC
and MIPS instruments, of the young (∼3Myr) sigma Orionis cluster.
We identify 336 stars as members of the cluster, using optical and
near-infrared color-magnitude diagrams. Using the spectral energy
distribution slopes in the IRAC spectral range, we place objects into
several classes: non-excess stars, stars with optically thick disks
(such as classical T Tauri stars), class I (protostellar) candidates,
and stars with "evolved disks"; the last exhibit smaller IRAC excesses
than optically thick disk systems. In general, this classification
agrees with the location expected in IRAC-MIPS color-color diagrams
for these objects.
Description:
We have observed a field of ∼1730arcmin2 in the sigma Orionis
cluster using the four channels (3.6, 4.5, 5.8, and 8.0um) of the
InfraRed Array Camer.
In addition, 90% of this field was also observed using the 24um band
of the Multiband Imaging Spectrometer for Spitzer.
The IRAC observations presented here were taken on 2004 October 9.
Optical magnitudes were obtained from the CIDA Equatorial Variability
survey, which is being carried out using the QUEST I camera installed
at the Jurgen Stock Telescope (a 1m Schmidt telescope) of the
Venezuelan National Observatory at Llano del Hato.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 117 336 Members of the σ Orionis Cluster
table2.dat 103 133 Uncertain members of the σ Orionis Cluster
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See also:
J/A+A/419/249 : RJHKs photometry of sigma Ori low-mass stars (Scholz+, 2004)
J/AJ/128/2316 : BVRIJHKs photometry in sigma Ori cluster (Sherry+, 2004)
J/AN/325/740 : Astrophysical supplements to ASCC-2.5 (Kharchenko+, 2004)
J/AN/325/705 : RIJHKs of low-mass stars in sigma Ori (Bejar+, 2004)
J/AJ/129/907 : New Ori OB1 members (Briceno+, 2005)
J/MNRAS/356/89 : sigma Ori low-mass stars (Kenyon+, 2005)
J/MNRAS/356/1583 : RV of sigma Ori low-mass candidate memb. (Burningham+, 2005)
J/A+A/446/501 : XMM observations of sigma Ori cluster (Franciosini+, 2006)
J/A+A/466/917 : Brightest stars of sigma Orionis cluster (Caballero+, 2007)
J/A+A/478/667 : The Mayrit catalogue (Caballero, 2008)
J/A+A/488/167 : Low-mass stars in σ Ori and λ Ori (Sacco+ 2008)
J/MNRAS/385/2210 : Spectroscopy around lam Ori and sig Ori (Maxted+, 2008)
J/A+A/493/931 : Sigma Ori MAD observations (Bouy+, 2009)
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- [HHM2007] Identification number
6- 13 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
15- 22 F8.5 deg DEdeg Declination in decimal degrees (J2000)
24- 28 F5.2 mag 3.6mag Spitzer/IRAC 3.6 micron band magnitude
30- 33 F4.2 mag e_3.6mag Uncertainty in 3.6mag
35- 39 F5.2 mag 4.5mag Spitzer/IRAC 4.5 micron band magnitude
41- 44 F4.2 mag e_4.5mag Uncertainty in 4.5mag
46- 50 F5.2 mag 5.8mag Spitzer/IRAC 5.8 micron band magnitude
52- 55 F4.2 mag e_5.8mag Uncertainty in 5.8mag
57- 61 F5.2 mag 8.0mag Spitzer/IRAC 8.0 micron band magnitude
63- 66 F4.2 mag e_8.0mag Uncertainty in 8.0mag
68- 72 F5.2 mag 24mag ? Spitzer/MIPS 24.0 micron band magnitude
74- 77 F4.2 mag e_24mag ? Uncertainty in 24.0mag
79- 83 F5.2 mag Vmag ? The V band magnitude (only for table1)
85- 88 F4.2 mag e_Vmag ? Uncertainty in Vmag (only for table1)
90 A1 --- r_Vmag Reference (only for table1) (1)
92 I1 --- V [0/1]? 1=variable, 0=non-variable (table1 only)
94 I1 --- X [0/1]? 1=X-ray emission (able1 only)
96-101 A6 --- Disk Disk classification (4)
103 I1 --- f_Disk [1/6]? Discrepancy in disk classification (5)
105-117 A13 --- Refs Known member reference(s) (only for table1) (1)
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Note (1): References as follows:
q = CIDA survey
1 = Barrado y Navascues et al. (2003A&A...404..171B 2003A&A...404..171B)
2 = Bejar et al. (1999ApJ...521..671B 1999ApJ...521..671B)
3 = Bejar et al. (2001ApJ...556..830B 2001ApJ...556..830B)
4 = Bejar et al. (2004, Cat. J/AN/325/705)
5 = Burningham et al. (2005, Cat. J/MNRAS/356/1583)
6 = Kenyon et al. (2005, Cat. J/MNRAS/356/89)
7 = Kharchenko et al. (2004, Cat. J/AN/325/740)
8 = Oliveira et al. (2006MNRAS.369..272O 2006MNRAS.369..272O)
9 = Sherry et al. (2004, Cat. J/AJ/128/2316)
10 = Scholz & Eisloffel (2004, Cat. J/A+A/419/249)
11 = Zapatero Osorio et al. (2002A&A...384..937Z 2002A&A...384..937Z)
12 = Jeffries et al. (2006MNRAS.371L...6J 2006MNRAS.371L...6J)
Note (4): Disk class as follows:
III = diskless
II = thick disk
I = class I candidate
EV = evolved disk
TD = transition disk candidate
DD = Debris disk candidate
Note (5): Flag on Disk as follows:
1 = Classified as III in Sect. 4.2 (systems have essentially no
inner disk emission, with α←2.56)
2 = Classified as EV in Sect. 4.2 (evolved disks, -2.56≲α←1.8)
3 = Classified as II in Sect. 4.2 (systems with α<0)
4 = Classified as I in Sect. 4.2 (systems with α>0)
5 = Possible giant in the J-H versus H-K color-color diagram.
6 = Radial velocity consistent for stars in the older
population (Jeffries et al., 2006MNRAS.371L...6J 2006MNRAS.371L...6J)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 22-May-2009