J/AJ/133/2072 Spitzer observations of NGC 2362 (Dahm+, 2007)
Spitzer observations of NGC 2362: primordial disks at 5 Myr.
Dahm S.E., Hillenbrand L.A.
<Astron. J., 133, 2072-2086 (2007)>
=2007AJ....133.2072D 2007AJ....133.2072D
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Photometry, infrared
Keywords: accretion, accretion disks -
open clusters and associations: individual (NGC 2362) -
stars: formation - stars: pre-main sequence
Abstract:
We present results from a mid-infrared imaging survey of the ∼5Myr old
cluster NGC 2362 carried out with the Infrared Array Camera (IRAC) on
board the Spitzer Space Telescope. The archival mid-infrared data were
merged with extant Halpha emission data, optical and near-infrared
photometry, and moderate-resolution optical spectroscopy to identify
the remnant disk-bearing population of the cluster and to estimate the
fraction of stars that still retain primordial circumstellar disks.
The principal sample of 232 suspected cluster members with masses
ranging from ∼10 to 0.3M☉ (B2-M5 spectral types) was drawn from
known Halpha emission stars, X-ray-detected stars from a single 100ks
archival Chandra observation, and established lithium-rich stars. A
second sample of 153 stars over a similar mass range whose membership
status was based on optical photometry alone was also examined.
Description:
The Spitzer Space Telescope mapped the cluster region under program ID
37 (principal investigator [PI]: G. Fazio) using IRAC in a shallow 7x6
mosaic, with individual field centers separated by ∼4.8'.
The optical (VRcIc) and NIR (JHK) imaging and the Wide Field Grism
Spectrograph (WFGS) Halpha observations of NGC 2362 were obtained using
the University of Hawaii 2.2m telescope on Mauna Kea.
The deep Chandra Advanced CCD Imaging Spectrometer (ACIS) observation
of NGC 2362 was made on 2003 December 29, observation ID 4469
(PI: S. Murray), with a nominal integration time of 100ks.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 132 232 Activity/Lithium Selected Members of NGC 2362
table2.dat 107 105 Photometric Membership Sample of NGC 2362
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See also:
J/AJ/130/1805 : Hα emission stars in NGC 2362 (Dahm+, 2005)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- DH Running star identification number (1)
5 I1 h RAh Hour of Right Ascension (J2000)
7- 8 I2 min RAm Minute of Right Ascension (J2000)
10- 14 F5.2 s RAs Second of Right Ascension (J2000)
16 A1 --- DE- Sign of the Declination (J2000)
17- 18 I2 deg DEd Degree of Declination (J2000)
20- 21 I2 arcmin DEm Arcminute of Declination (J2000)
23- 26 F4.1 arcsec DEs Arcsecond of Declination (J2000)
28- 32 F5.2 mag Vmag ? Dahm (2005, J/AJ/130/1805) V band magnitude
34- 38 F5.2 mag V-Rc ? Dahm (2005, J/AJ/130/1805) V-Rc color index
40- 44 F5.2 mag V-Ic ? Dahm (2005, J/AJ/130/1805) V-Ic color index
46- 50 F5.2 mag Jmag ? The J band magnitude (2)
52- 56 F5.2 mag J-H ? The J-H color index (2)
58- 62 F5.2 mag H-Ks ? The H-Ks color index (2)
64- 68 F5.2 mag 3.6mag ? Spitzer/IRAC 3.6µm band magnitude
70- 73 F4.2 mag e_3.6mag ? Error in 3.6mag
75- 79 F5.2 mag 4.5mag ? Spitzer/IRAC 4.5µm band magnitude
81- 84 F4.2 mag e_4.5mag ? Error in 4.5mag
86- 90 F5.2 mag 5.8mag ? Spitzer/IRAC 5.8µm band magnitude
91 A1 --- u_5.8mag Uncertainty flag on 5.8mag
93- 96 F4.2 mag e_5.8mag ? Error in 5.8mag
98-102 F5.2 mag 8.0mag ? Spitzer/IRAC 8.0µm band magnitude
104-107 F4.2 mag e_8.0mag ? Error in 8.0mag
109-114 F6.2 0.1nm EWHa ? Hα equivalent width, in table1 only (3)
116-117 A2 --- f_EWHa [abce ?:] Flag on EWHa (4)
119-122 F4.2 0.1nm EW6708 ? LiI(6708Å) line equivalent width,
in table1 only (5)
124 A1 --- u_EW6708 [:N] Uncertain or absent EW6708 (6)
126-129 A4 --- SpType Spectral type, in table1 only
131-132 A2 --- X [XND ] An X-ray detection, in table1 only (7)
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Note (1): Objects identified as Cl* NGC 2362 DH NNN in Simbad.
Note (2): From 2MASS or Dahm (2005, Cat. J/AJ/130/1805).
Note (3): In Angstroms. A "+" value implies emission.
Note (4): Flag on EWHa as follows:
a = absorption
b = WFGS spectrum blended or overlapped
c = No emission or absorption present at Hα, level continuum
e = emission probable
blank = no data available
? or : = value uncertain
Note (5): In Angstroms, obtained with the Gemini Multi-Object Spectrograph
(GMOS) on Gemini-North . Blank values indicate no data available.
Note (6): Flag on EW6708 as follows:
N = not present
: = value uncertain
Note (7): X = X-ray detection,
ND = X-ray non-detection
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 22-Mar-2009