J/ApJ/702/1507 Mid-IR photometry in IC 1396A (Morales-Calderon+, 2009)
Mid-infrared variability of protostars in IC 1396A.
Morales-Calderon M., Stauffer J.R., Rebull L., Whitney B.A.,
Barrado y Navascues D., Ardila D.R., Song I., Brooke T.Y., Hartmann L.,
Calvet N.
<Astrophys. J., 702, 1507-1529 (2009)>
=2009ApJ...702.1507M 2009ApJ...702.1507M
ADC_Keywords: Photometry, infrared ; YSOs ; Molecular clouds
Keywords: infrared: stars - stars: pre-main sequence - stars: variables: other
Abstract:
We have used Spitzer/Infrared Array Camera (IRAC) to conduct a
photometric monitoring program of the IC1396A dark globule in order to
study the mid-IR (3.6-8um) variability of the heavily embedded young
stellar objects (YSOs) present in that area. We obtained light curves
covering a 14 day timespan with a twice daily cadence for 69 YSOs, and
continuous light curves with approximately 12s cadence over 7hr for 38
YSOs. Typical accuracies for our relative photometry were 1%-2% for
the long timespan data and a few millimagnitude, corresponding to less
than 0.5%, for the 7hr continuous "staring-mode" data. More than half
of the YSOs showed detectable variability, with amplitudes from
∼0.05mag to ∼0.2mag. One star, IC1396A-47, shows a 3.5hr periodic
light curve; this object may be a PMS Delta Scuti star.
Description:
Thus, we have used a recent DDT program (PI: Soifer, PID:470) to study
mid-IR variability of protostars in the very young star-forming
globule IC1396A. The data were collected from 2008 January 24 to
February 6 and observations were performed with two distinctly
different observing modes (mapping and staring).
We have used previous observations from the Spitzer archive to derive
the fluxes of our new targets at 24um (PID:58, PI: Rieke).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 144 15 New candidates photometry from the co-added
deep mosaics
table2.dat 116 69 Long-term variability: main results from mapping
data
table3.dat 76 1148 Time series in the four IRAC bands for the
variable YSOs of our sample
table6.dat 121 46 Photometry for the variable objects found in the
field
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJ/698/324 : Spitzer IRDCs (Ragan+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/638/897 : IR photometry in Trumpler 37 and NGC 7160 (Sicilia-Aguilar+,
2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [IC1396A-]
9- 10 I2 --- ID [60/74] YSO candidate name
(<[MSR2009] IC1396A-NN> in Simbad) (1)
11 A1 --- f_ID [d] source close to a brighter one (2)
13- 14 I2 h RAh Hour of right ascension (J2000)
16- 17 I2 min RAm Minute of right ascension (J2000)
19- 23 F5.2 s RAs Second of right ascension (J2000)
25 A1 --- DE- Sign of declination (J2000)
26- 27 I2 deg DEd Degree of declination (J2000)
29- 30 I2 arcmin DEm Arcminute of declination (J2000)
32- 35 F4.1 arcsec DEs Arcsecond of declination (J2000)
37- 42 F6.3 mag Jmag ? 2MASS J-band magnitude
43 A1 --- l_Jmag [c] c: upper limit
45- 49 F5.3 mag e_Jmag ? Jmag uncertainty
51- 56 F6.3 mag Hmag ? 2MASS H-band magnitude
57 A1 --- l_Hmag [c] c: upper limit
59- 63 F5.3 mag e_Hmag ? Hmag uncertainty
65- 70 F6.3 mag Ksmag ? 2MASS Ks-band magnitude
71 A1 --- l_Ksmag [c] c: upper limit
73- 77 F5.3 mag e_Ksmag ? Ksmag uncertainty
79- 84 F6.3 mag [3.6] Spitzer/IRAC 3.6um-band magnitude
86- 90 F5.3 mag e_[3.6] 3.6um-band magnitude uncertainty
92- 97 F6.3 mag [4.5] Spitzer/IRAC 4.5um-band magnitude
99-103 F5.3 mag e_[4.5] 4.5um-band magnitude uncertainty
105-110 F6.3 mag [5.8] Spitzer/IRAC 5.8um-band magnitude
112-116 F5.3 mag e_[5.8] 5.8um-band magnitude uncertainty
118-123 F6.3 mag [8.0] ? Spitzer/IRAC 8.0um-band magnitude
125-129 F5.3 mag e_[8.0] ? 8.0um-band magnitude uncertainty
131-135 F5.3 mag [24] ? Spitzer 24um-band magnitude
137-141 F5.3 mag e_[24] ? 24um-band magnitude uncertainty
143-144 A2 --- Class Candidate class (I or II)
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Note (1): Sicilia-Aguilar et al. (2006, Cat. J/ApJ/638/897)
identified 57 YSOs in this region and there are another two objects
that were identified by Reach et al. (2005PASP..117..978R 2005PASP..117..978R), thus we
name our new candidate members beginning with number 60.
Note (2): d = This object is very faint at 24um and it is located too close
to a brighter object to derive a reliable magnitude.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [IC1396A-]
9- 10 I2 --- ID [1/74] YSO candidate identification
(<[MSR2009] IC1396A-NN> in Simbad)(1)
11 A1 --- f_ID [f] Uncertain member (2)
13- 14 I2 h RAh Hour of right ascension (J2000)
16- 17 I2 min RAm Minute of right ascension (J2000)
19- 23 F5.2 s RAs Second of right ascension (J2000)
25 A1 --- DE- Sign of declination (J2000)
26- 27 I2 deg DEd Degree of declination (J2000)
29- 30 I2 arcmin DEm Arcminute of declination (J2000)
32- 35 F4.1 arcsec DEs Arcsecond of declination (J2000)
37- 38 A2 --- SA YSO class as in Sicilia-Aguilar et al. (2006,
Cat. J/ApJ/638/897)
40- 51 A12 --- R04 ID and YSO Class as in Reach et al.
(2004ApJS..154..385R 2004ApJS..154..385R)
53- 55 A3 --- Class YSO class in this paper (3)
56 A1 --- f_Class [e] e: classification in disagreement with
Sicilia-Aguilar et al. (2006, Cat. J/ApJ/638/897)
58- 63 F6.3 mag [3.6] Spitzer/IRAC 3.6um-band magnitude
65- 69 F5.3 mag e_[3.6] 3.6mag uncertainty
71- 75 F5.3 --- rms1 3.6um rms amplitude
77 A1 --- V1 [N/V] χ2 test variability result
79- 82 F4.1 d T1 ? Variability timescale for the IRAC Ch. 1 (4)
84- 89 F6.3 mag [4.5] ? Spitzer/IRAC 4.5um-band magnitude
91- 95 F5.3 mag e_[4.5] ? 4.5mag uncertainty
97-101 F5.3 --- rms2 ? 4.5um rms amplitude
103 A1 --- V2 [N/V] χ2 test variability result
105-107 F3.1 d T2 ? Variability timescale for the IRAC Ch. 2 (4)
109-114 E6.2 --- Js Stetson J statistic (Js>0.55 for a variable)
116 A1 --- Var [N/V] Final variability tag
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Note (1): Objects are named following the order in Table 6 of
Sicilia-Aguilar et al. (2006, Cat. J/ApJ/638/897; note that not all
their members are included), objects 58 and 59 are YSOs from Reach et
al. (2004ApJS..154..385R 2004ApJS..154..385R) not in common with Sicilia-Aguilar et al.
(2006, Cat. J/ApJ/638/897), and objects from 60 to 74 are our new
candidate members from Table 1.
Note (2): f = Uncertain cluster members following Sicilia-Aguilar et al.
(2006, Cat. J/ApJ/638/897).
Note (3): Members in Sicilia-Aguilar et al. (2006, Cat. J/ApJ/638/897) that
do not show IR excess in our data have been classified as Class III.
Note (4): Variability timescales rather than periods since the timespan of
our observations are not long enough to confirm the periodicity.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- --- [IC1396A-]
9- 10 I2 --- ID [1/74] Object ID
(<[MSR2009] IC1396A-NN> in Simbad)
12- 24 F13.7 d MJD Modified Julian Date
26- 31 F6.3 mag [3.6] ?=99.999 Spitzer/IRAC 3.6 micron band magnitude
33- 37 F5.3 mag e_[3.6] ?=9.999 Uncertainty in 3.6mag
39- 44 F6.3 mag [4.5] ?=99.999 Spitzer/IRAC 4.5 micron band magnitude
46- 50 F5.3 mag e_[4.5] ?=9.999 Uncertainty in 4.5mag
52- 57 F6.3 mag [5.8] ?=99.999 Spitzer/IRAC 5.8 micron band magnitude
59- 63 F5.3 mag e_[5.8] ?=9.999 Uncertainty in 5.8mag
65- 70 F6.3 mag [8.0] ?=99.999 Spitzer/IRAC 8.0 micron band magnitude
72- 76 F5.3 mag e_[8.0] ?=9.999 Uncertainty in 8.0mag
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq Object internal identification
(<[MSR2009] NNNN> in Simbad)
6- 7 I2 h RAh Hour of right ascension (J2000)
9- 10 I2 min RAm Minute of right ascension (J2000)
12- 16 F5.2 s RAs Second of right ascension (J2000)
18 A1 --- DE- Sign of declination (J2000)
19- 20 I2 deg DEd Degree of declination (J2000)
22- 23 I2 arcmin DEm Arcminute of declination (J2000)
25- 28 F4.1 arcsec DEs Arcsecond of declination (J2000)
30- 35 F6.3 mag Jmag ? 2MASS J-band magnitude
36 A1 --- f_Jmag [c] c: upper limit
38- 42 F5.3 mag e_Jmag ? Jmag uncertainty
44- 49 F6.3 mag Hmag ? 2MASS H-band magnitude
51- 55 F5.3 mag e_Hmag ? Hmag uncertainty
57- 62 F6.3 mag Ksmag ? 2MASS Ks-band magnitude
63 A1 --- f_Ksmag [c] c: upper limit
65- 69 F5.3 mag e_Ksmag ? Ksmag uncertainty
71- 76 F6.3 mag [3.6] Spitzer/IRAC 3.6um-band magnitude
78- 82 F5.3 mag e_[3.6] Spitzer/IRAC 3.6um-band magnitude uncertainty
84- 89 F6.3 mag [4.5] Spitzer/IRAC 4.5um-band magnitude
91- 95 F5.3 mag e_[4.5] Spitzer/IRAC 4.5um-band magnitude uncertainty
97-102 F6.3 mag [5.8] ? Spitzer/IRAC 5.8um-band magnitude
104-108 F5.3 mag e_[5.8] ? Spitzer/IRAC 5.8um-band magnitude uncertainty
110-115 F6.3 mag [8.0] ? Spitzer/IRAC 8.0um-band magnitude
117-121 F5.3 mag e_[8.0] ? Spitzer/IRAC 8.0um-band magnitude uncertainty
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Oct-2011