J/AJ/150/118 YSOVAR infrared photometry in IRAS 20050+2720 (Poppenhaeger+, 2015)
YSOVAR: mid-infrared variability of young stellar objects and their disks in the
cluster IRAS 20050+2720.
Poppenhaeger K., Cody A.M., Covey K.R., Gunther H.M., Hillenbrand L.A.,
Plavchan P., Rebull L.M., Stauffer J.R., Wolk S.J., Espaillat C.,
Forbrich J., Gutermuth R.A., Hora J.L., Morales-Calderon M., Song I.
<Astron. J., 150, 118 (2015)>
=2015AJ....150..118P 2015AJ....150..118P (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, variable ; Photometry, infrared
Keywords: accretion, accretion disks - infrared: stars - protoplanetary disks -
stars: pre-main sequence - stars: variables: general
Abstract:
We present a time-variability study of young stellar objects (YSOs) in
the cluster IRAS 20050+2720, performed at 3.6 and 4.5µm with the
Spitzer Space Telescope; this study is part of the Young Stellar
Object VARiability (YSOVAR) project. We have collected light curves
for 181 cluster members over 60 days. We find a high variability
fraction among embedded cluster members of ca. 70%, whereas young
stars without a detectable disk display variability less often (in ca.
50% of the cases) and with lower amplitudes. We detect periodic
variability for 33 sources with periods primarily in the range of 2-6
days. Practically all embedded periodic sources display additional
variability on top of their periodicity. Furthermore, we analyze the
slopes of the tracks that our sources span in the color-magnitude
diagram (CMD). We find that sources with long variability time scales
tend to display CMD slopes that are at least partially influenced by
accretion processes, while sources with short variability timescales
tend to display extinction-dominated slopes. We find a tentative trend
of X-ray detected cluster members to vary on longer timescales than
the X-ray undetected members.
Description:
We obtained mid-infrared light curves of young stellar objects in IRAS
20050+2720 during the Spitzer warm mission. The central region of IRAS
20050+2720 was observed with Spitzer from 2010 June 12 to 2010 August
10, using the 3.6µm and 4.5µm channel (hereafter [3.6] and
[4.5]) of the IRAC camera
IRAS 20050+2720 was observed with the Chandra X-ray Observatory in
three observations using the ACIS-I camera in VFAINT mode (ObsIDs
6438, 7254, 8492, PI Wolk). The exposure times and observation epochs
were 21ks (2006 January 07), 23ks (2006 December 10), and 51ks (2007
January 29), with a total exposure time of 93.95ks, i.e., ∼26hr. This
work was performed in the context of a single-epoch infrared study of
IRAS 20050+2720 (Gunther et al. 2012, cat. J/AJ/144/101), and we use
their derived X-ray properties here.
PAIRITEL is a 1.3m robotic telescope operated by the Smithsonian
Astrophysical Observatory on Mount Hopkins, AZ; it was operational
from 2004 to 2013. It was equipped with the JHKs camera previously
used for the 2MASS project. Photometric observations of IRAS20050+2720
were obtained during 31 nights between 2010 June 19 and 2012 July 10.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 659 187 Source designations, flux densities, and light
curve properties
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See also:
J/AJ/148/122 : YSOVAR: infrared photometry in Lynds 1688 (Gunther+, 2014)
J/AJ/144/101 : Multiwavelength data of IRAS 20050+2720 (Guenther+, 2012)
J/ApJ/753/149 : YSOVAR: 6 eclipsing binaries in Orion (Morales-Calderon+, 2012)
J/ApJ/733/50 : MIR photometric monitoring of the ONC (Morales-Calderon+, 2011)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/A+A/481/93 : CO and HC3N maps of IRAS 20050+2720 (Beltran+, 2008)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 14 F14.9 deg RAdeg Right Ascension in decimal degrees (J2000)
16- 28 F13.10 deg DEdeg Declination in decimal degrees (J2000)
30- 35 A6 --- --- [SSTYSV]
37- 55 A19 --- SSTYSV IAU designation within the Spitzer Space
Telescope (SST) Young Stellar Object
VARiability (YSOVAR) program
(JHHMMSS.ss+DDMMSS.s)
57- 85 A29 --- SIMBAD Main Simbad identifier for an object
87- 89 A3 --- Cl Infrared class according to SED slope
(F, I, II, or III) (1)
91- 95 A5 --- Std Source in YSOVAR standard set? (False or
True) (2)
97-101 A5 --- Mm Is source cluster member without light
curve? (False or True)
103-105 I3 --- N3.6 [0/102] Number of Spitzer/IRAC 3.6µm
band datapoints
107-109 I3 --- N4.5 [0/101] Number of Spitzer/IRAC 4.5µm
band datapoints
111-118 F8.5 mag med3.6 [6.7/16.2]? Median Spitzer/IRAC 3.6µm
band magnitude
120-127 F8.5 mag med4.5 [6.3/16]? Median Spitzer/IRAC 4.5µm band
magnitude
129-141 F13.10 mag <[3.6]> [6.7/16.2]? Mean Spitzer/IRAC 3.6µm band
magnitude
143-156 F14.11 mag <[4.5]> [6.3/16]? Mean Spitzer/IRAC 4.5µm band
magnitude
158-164 F7.4 mag m3.6 [6.6/16.1]? Minimum Spitzer/IRAC 3.6µm
band magnitude
166-172 F7.4 mag m4.5 [5.7/15.9]? Minimum Spitzer/IRAC 4.5µm
band magnitude
174-180 F7.4 mag M3.6 [6.7/16.2]? Maximum Spitzer/IRAC 3.6µm
band magnitude
182-188 F7.4 mag M4.5 [5.7/16.2]? Maximum Spitzer/IRAC 4.5µm
band magnitude
190-197 F8.6 mag s_<[3.6]> [0/0.56]? Width of Spitzer/IRAC 3.6µm
band distribution (3)
199-206 F8.6 mag s_<[4.5]> [0/0.53]? Width of Spitzer/IRAC 4.5µm
band distribution (3)
208-210 F3.1 --- Var [0/1] Variability caused by light curve
artifacts? (0=yes, 1=no)
212-227 F16.13 --- Stet [-1.4/16.7]? Stetson index for a two-band
light curve
229-244 F16.12 --- chiM3.6 [0.13/291]? Reduced χ2 to mean for
Spitzer/IRAC 3.6µm band
246-261 F16.12 --- chiM4.5 [0.4/655]? Reduced χ2 to mean for
Spitzer/IRAC 4.5µm band
263-271 F9.6 d Per [0.28/14.2]? Adopted period of light curve
273-283 E11.7 --- FAP [0/0.03]? False Alarm Probability of
adopted period
285-299 F15.12 d t3.6 [0.2/15.8]? Spitzer/IRAC 3.6µm band
decay time of autocorrelation function
301-315 F15.12 d t4.5 [0.3/15.7]? Spitzer/IRAC 4.5µm band
decay time of autocorrelation function
317-331 F15.11 deg CMD [8/159]? Fitted CMD slope angle
333-347 F15.12 deg e_CMD [0.4/90]? The 1σ error in CMD
349-364 F16.12 --- chiP3.6 [0.3/224]? Residual scatter in Spitzer/IRAC
3.6µm band phase-folded fitted light
curves
366-381 F16.12 --- chiP4.5 [0.4/534]? Residual scatter in Spitzer/IRAC
4.5µm band phase-folded fitted light
curves
383-395 F13.10 mag Jmag1 [10.76/19.71]? Median PAIRITEL J band
magnitude
397-409 F13.10 mag Hmag1 [10/17.2]? Median PAIRITEL H band magnitude
411-424 F14.11 mag Kmag1 [9/16.4]? Median PAIRITEL Ks band magnitude
426-432 F7.4 mag Umag [11/16.1]? FLWO/KeplerCam U band
magnitude (4)
434-441 F8.6 mag e_Umag [0.1/0.11]? Statistical error in Umag
443-449 F7.4 mag Bmag [11/16]? FLWO/KeplerCam B band magnitude (4)
451-458 F8.6 mag e_Bmag [0.1/0.101]? Statistical error in Bmag
460-466 F7.4 mag Vmag [10.6/14.3]? FLWO/KeplerCam V band
magnitude (4)
468-475 F8.6 mag e_Vmag [0.1/0.1002]? Statistical error in Vmag
477-483 F7.4 mag Rmag [10.3/18.7]? FLWO/KeplerCam R band
magnitude (4)
485-492 F8.6 mag e_Rmag [0.1/0.12]? Statistical error in Rmag
494-500 F7.4 mag Imag [10/17]? FLWO/KeplerCam I band magnitude (4)
502-509 F8.6 mag e_Imag [0.1/0.103]? Statistical error in Imag
511-516 F6.3 mag Jmag2 [9.7/17]? 2MASS J band magnitude
518-522 F5.3 mag e_Jmag2 [0.02/0.2]? Statistical error in Jmag2
524-529 F6.3 mag Hmag2 [9.5/16.1]? 2MASS H band magnitude
531-535 F5.3 mag e_Hmag2 [0.02/0.2]? Statistical error in Hmag2
537-542 F6.3 mag Kmag2 [8.7/15.3]? 2MASS Ks band magnitude
544-548 F5.3 mag e_Kmag2 [0.01/0.2]? Statistical error in Kmag2
550-557 F8.5 mag [3.6] [6.7/17]? Cryogenic Spitzer/IRAC 3.6µm
band magnitude
559-568 F10.8 mag e_[3.6] [0.002/0.15]? Statistical error in [3.6]
570-577 F8.5 mag [4.5] [5.8/16.3]? Cryogenic Spitzer/IRAC 4.5µm
band magnitude
579-588 F10.8 mag e_[4.5] [0.002/0.14]? Statistical error in [4.5]
590-597 F8.5 mag [5.8] [4.9/14.5]? Cryogenic Spitzer/IRAC 5.8µm
band magnitude
599-608 F10.8 mag e_[5.8] [0.001/0.29]? Statistical error in [5.8]
610-617 F8.5 mag [8.0] [3.7/13.8]? Cryogenic Spitzer/IRAC 8.0µm
band magnitude
619-628 F10.8 mag e_[8.0] [0.001/0.44]? Statistical error in [8.0]
630-638 F9.7 mag [24] [0/9.8]? Cryogenic Spitzer/MIPS 24µm band
magnitude
640-649 F10.8 mag e_[24] [0/0.7]? Statistical error in [24]
651-659 F9.5 ct/ks/m2 FX [1.9/274.4]? X-ray flux count rate
(in 10-7ct/s/cm2) (4)
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Note (1): Spectral index code is defined as follows:
I = Class I source with a spectral slope α>0.3
(α=dlogλFλ/dlogλ);
F = Flat-spectrum source (-0.3<α<0.3);
II = Class II source (-1.6<α←0.3);
III = Class III source (α←1.6).
Note (2): Cluster member with light curve?
Note (3): From 10% to 90%.
Note (4): From Gunther et al. 2012 (cat. J/AJ/144/101).
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 29-Oct-2015