J/AJ/150/132 JHK photometry of 1203 variables in ONC (Rice+, 2015)
Near-infrared variability in the Orion Nebula Cluster.
Rice T.S., Reipurth B., Wolk S.J., Vaz L.P., Cross N.J.G.
<Astron. J., 150, 132 (2015)>
=2015AJ....150..132R 2015AJ....150..132R (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, variable ; Photometry, infrared
Keywords: infrared: stars - stars: formation - stars: pre-main sequence -
stars: variables: T Tauri, Herbig Ae/Be
Abstract:
Using UKIRT on Mauna Kea, we have carried out a new near-infrared J,
H, K monitoring survey of almost a square degree of the star-forming
Orion Nebula Cluster with observations on 120 nights over three
observing seasons, spanning a total of 894 days. We monitored ∼15000
stars down to J∼20 using the WFCAM instrument, and have extracted 1203
significantly variable stars from our data. By studying variability in
young stellar objects (YSOs) in the H-K, K color-magnitude diagram, we
are able to distinguish between physical mechanisms of variability.
Many variables show color behavior indicating either dust-extinction
or disk/accretion activity, but we find that when monitored for longer
periods of time, a number of stars shift between these two variability
mechanisms. Further, we show that the intrinsic timescale of
disk/accretion variability in young stars is longer than that of
dust-extinction variability. We confirm that variability amplitude is
statistically correlated with evolutionary class in all bands and
colors. Our investigations of these 1203 variables have revealed 73
periodic AA Tau type variables, many large-amplitude and long-period
(P>15 days) YSOs, including three stars showing widely spaced periodic
brightening events consistent with circumbinary disk activity, and
four new eclipsing binaries. These phenomena and others indicate the
activity of long-term disk/accretion variability processes taking
place in young stars. We have made the light curves and associated
data for these 1203 variables available online.
Description:
Our data comprise J, H, K observations of a 0.9°*0.9° field
toward the Orion Nebula Cluster (ONC) that were taken with the Wide
Field Camera (WFCAM) instrument on the 3.8m UKIRT, which sits atop
Mauna Kea, HI at 4194m elevation. Observations have been taken on 120
nights between 2006 October and 2009 April over three observing
seasons: 2006 October 26-2007 April 21, 2007 November 21-2007 December
2, and 2008 November 8-2009 April 7. We monitored ∼15000 stars down to
J∼20 using the WFCAM instrument, and have extracted 1203 significantly
variable stars from our data.
The observations came from UKIRT/WFCAM programmes U/06B/H54,
U/07B/H60B, and U/09A/H33 and were combined into a single WFCAM
Science Archive (WSA) combined programme WSERV5. The data in this
paper come from the data release WSERV5v20120208, and can be accessed
at http://surveys.roe.ac.uk/wsa.
The coordinates, SIMBAD cross-matched names, median WFCAM photometry,
Spitzer photometry, and evolutionary classes of all 1203 variables are
listed in Table2. In Tables 4 and 5, we show the variability
statistics, including derived color slopes, for all periodic and
nonperiodic stars in our data set, respectively. We identify long-term
periodic stars in Table6. In Table7 we list the four newly discovered
eclipsing binaries and their basic data, together with nine other
eclipsing binaries that fall within our WFCAM field.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 159 1203 Basic properties of 1203 significantly variable stars
table4.dat 123 539 Variability properties of periodic stars
table5.dat 123 664 Variability properties of nonperiodic stars
table6.dat 13 14 Long-period periodic stars
table7.dat 99 13 Eclipsing binaries toward M42 within WFCAM field
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See also:
J/ApJ/768/99 : X-ray survey of YSOs in Orion A (Pillitteri+, 2013)
J/ApJS/208/28 : Hα survey in the ONC (Szegedi-Elek+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/ApJ/753/149 : YSOVAR: six EBs in Orion (Morales-Calderon+, 2012)
J/ApJ/748/14 : ONC population data from WFI observations (Da Rio+, 2012)
J/AJ/144/192 : Orion A and B Spitzer survey. I. YSO catalog (Megeath+, 2012)
J/A+A/534/A10 : HST/NICMOS III imaging in ONC (Andersen+, 2011)
J/ApJ/733/50 : MIR photometric monitoring of ONC (Morales-Calderon+, 2011)
J/ApJ/722/1092 : Optical photometry of the ONC. II. (Da Rio+, 2010)
J/A+A/502/883 : I phot. of very low mass ONC stars (Rodriguez-Ledesma+, 2009)
J/MNRAS/400/603 : New variables in ONC (Parihar+, 2009)
J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)
J/AJ/129/1534 : Mid-IR photometry in the Orion Nebula (Robberto+, 2005)
J/ApJ/573/366 : Infrared photometry of Trapezium cluster (Muench+, 2002)
J/AJ/121/3160 : JHK photometry near the Trapezium region (Carpenter+, 2001)
J/ApJ/540/236 : KH photometry of Orion Nebula Cluster (Hillenbrand+, 2000)
http://surveys.roe.ac.uk/wsa : WSA-WFCAM Science Archive
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star [1/1227] Identifier of the variable in the
Orion Nebula Cluster (ONC) (ONCvar identifier)
6- 14 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
16- 24 F9.6 deg DEdeg Declination in decimal degrees (J2000)
26- 54 A29 --- Simbad Simbad alternative identifier
56 I1 --- Q [0/2] Quality class (1)
58 I1 --- P [0/1] Periodic flag (1=periodic, 0=not periodic)
60- 66 F7.3 mag Jmag [9.6/20.3]?=-99.999 Median UKIRT/WFCAM J band
magnitude
68- 72 F5.3 mag e_Jmag [0.02/0.5]?=9.999 Representative error in Jmag
74- 80 F7.3 mag Hmag [9.2/18.4]?=-99.999 Median UKIRT/WFCAM H band
magnitude
82- 86 F5.3 mag e_Hmag [0.02/0.17]?=9.999 Representative error in Hmag
88- 94 F7.3 mag Kmag [8.7/17.5]?=-99.999 Median UKIRT/WFCAM K band
magnitude
96-100 F5.3 mag e_Kmag [0.02/0.16]?=9.999 Representative error in Kmag
102-108 F7.3 mag [3.6] [5.8/16.5]?=-99.999 Spitzer/IRAC 3.6µm band
magnitude
110-114 F5.3 mag e_[3.6] [0/0.16]?=9.999 Uncertainty in [3.6]
116-122 F7.3 mag [4.5] [4.8/15.8]?=-99.999 Spitzer/IRAC 4.5µm band
magnitude
124-128 F5.3 mag e_[4.5] [0.001/0.13]?=9.999 Uncertainty in [4.5]
130-136 F7.3 mag [5.8] [3.6/14.6]?=-99.999 Spitzer/IRAC 5.8µm band
magnitude
138-142 F5.3 mag e_[5.8] [0.001/0.5]?=9.999 Uncertainty in [5.8]
144-150 F7.3 mag [8.0] [2.6/13.6]?=-99.999 Spitzer/IRAC 8.0µm band
magnitude
152-156 F5.3 mag e_[8.0] [0.001/0.2]?=9.999 Uncertainty in [8.0]
158-159 A2 --- Class Classification (G1)
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Note (1): Quality classes are defined in Section 3.1 and Appendix A:
0 = The lowest quality class; all bands have some defect;
1 = One or two bands have some defect;
2 = The highest quality class; no band has a defect.
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Byte-by-byte Description of file: table[45].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Star [1/1227] Identifier of the variable in the
Orion Nebula Cluster (ONC) (ONCvar identifier)
6- 8 I3 --- NJ [0/328] Number of J band observations (2)
10- 12 I3 --- NH [0/427] Number of H band observations (2)
14- 16 I3 --- NK [0/408] Number of K band observations (2)
18- 24 F7.3 mag DJmag [0/3]?=-99.999 The J band magnitude range
(robust) ΔJ
26- 32 F7.3 mag DHmag [0.04/2.5]?=-99.999 The H band magnitude
range (robust) ΔH
34- 40 F7.3 mag DKmag [0.04/2]?=-99.999 The K band magnitude
range (robust) ΔK
42- 48 F7.3 mag D(J-H) [0/1.9]?=-99.999 The (J-H) color index range
(robust) ΔJ-H
50- 56 F7.3 mag D(H-K) [0/1.3]?=-99.999 The (H-K) color index range
(robust) ΔH-K
58- 64 F7.3 --- Slope1 [-0.7/2]?=-99.999 The (J-H), (H-K) color
slope m(J-H,H-K) (3)
66- 70 F5.3 --- e_Slope1 [0.01/0.3]?=9.999 Error in Slope1
72- 78 F7.3 --- Slope2 [-13.7/10.3]?=-99.999 The J, (J-H) slope
m(J,J-H) (3)
80- 84 F5.3 --- e_Slope2 [0.06/6]?=9.999 Error in Slope2
86- 92 F7.3 --- Slope3 [-10.1/8.2]?=-99.999 The K, (H-K) slope
m(K,H-K) (3)
94- 98 F5.3 --- e_Slope3 [0.04/3.6]?=9.999 Error in Slope3
100-106 F7.3 --- S [0.9/161] Stetson variability Index (defined in
Section 3.1)
108-110 A3 --- Band [ hjk] Bands used to compute S (J, H, or/and K)
112-118 F7.4 d Per [1.6/50]? Best fit period (only for the Table4)
120 I1 --- Q [0/2] Quality class (4)
122-123 A2 --- Class Classification (G1)
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Note (2): Some stars fall on overlap regions and are observed twice per night.
Note (3): A slope is only included if the orthogonal distance regression fit
yielded a confidence of better than 10% on the fit.
Note (4): Quality classes are defined in Section 3.1 and Appendix A:
0 = The lowest quality class; all bands have some defect;
1 = One or two bands have some defect;
2 = The highest quality class; no band has a defect.
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Star Identifier of the variable in the Orion Nebula
Cluster (ONC) (ONCvar identifier)
6- 11 F6.2 d Per Period
13 A1 --- LPB Long-Period Brightener (C=candidate, Y=definite
identification as such)
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- Star ? Identifier of the variable in the Orion Nebula
Cluster (ONC) (ONCvar identifier)
6- 15 A10 --- Name Common name
17- 33 A17 --- 2MASS 2MASS identifier
35- 36 I2 h RAh Hour of Right Ascension (J2000)
38- 39 I2 min RAm Minute of Right Ascension (J2000)
41- 45 F5.2 s RAs Second of Right Ascension (J2000)
47 A1 --- DE- Sign of the Declination (J2000)
48- 49 I2 deg DEd Degree of Declination (J2000)
51- 52 I2 arcmin DEm Arcminute of Declination (J2000)
54- 57 F4.1 arcsec DEs Arcsecond of Declination (J2000)
59- 63 F5.2 mag Imag ? The I band magnitude from literature
65- 69 F5.2 mag <Jmag> The mean J band magnitude (1)
71- 75 F5.2 mag <Hmag> The mean H band magnitude (1)
77- 81 F5.2 mag <Kmag> The mean K band magnitude (1)
83- 87 F5.2 d Per ? Period (2)
88 A1 --- f_Per [:?] Flag on Per (:=indicates a tentative period
fit)
90- 99 A10 --- Ref Reference (3)
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Note (1): From our photometry, or in the case of the three stars V1501 Ori,
tet1 Ori E, and [H97b]9209, which are all saturated in our data, from the
2MASS point source catalog (cat. II/246) or Carpenter et al. 2001
(cat. J/AJ/121/3160).
Note (2): Periods rounded to two decimals. Periods for the four new eclipsing
binaries are best estimates from the current data
Note (3): Reference codes are defined as follows:
Car08 = Cargile et al. (2008ApJ...674..329C 2008ApJ...674..329C);
Irw07 = Irwin et al. (2007MNRAS.380..541I 2007MNRAS.380..541I);
Mor12 = Morales-Calderon et al. 2012 (cat. J/ApJ/753/149);
Sta04 = Stassun et al. (2004ApJS..151..357S 2004ApJS..151..357S);
Sta06 = Stassun et al. (2006Natur.440..311S 2006Natur.440..311S).
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Global Notes:
Note (G1): Evolutionary classes are defined as below:
P = Protostar;
D = Disked;
ND = Non-Disked (classes derived from Megeath et al. 2012 (cat. J/AJ/144/192));
na = This source does not have a determined class in the Megeath et al. 2012
(cat. J/AJ/144/192) catalog, or does not appear at all in that catalog.
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 07-Apr-2016