J/ApJ/848/97 Young stellar variables with KELT for K2. I. (Rodriguez+, 2017)
Identification of young stellar variables with KELT for K2.
I. Taurus dippers and rotators.
Rodriguez J.E., Ansdell M., Oelkers R.J., Cargile P.A., Gaidos E.,
Cody A.M., Stevens D.J., Somers G., James D., Beatty T.G., Siverd R.J.,
Lund M.B., Kuhn R.B., Gaudi B.S., Pepper J., Stassun K.G.
<Astrophys. J., 848, 97 (2017)>
=2017ApJ...848...97R 2017ApJ...848...97R
ADC_Keywords: YSOs ; Photometry, SDSS ; Photometry, infrared ; Stars, variable
Keywords: circumstellar matter; protoplanetary disks; stars: pre-main sequence;
stars: variables: T Tauri, Herbig Ae/Be
Abstract:
One of the most well-studied young stellar associations,
Taurus-Auriga, was observed by the extended Kepler mission, K2, in the
spring of 2017. K2 Campaign 13 (C13) is a unique opportunity to study
many stars in this young association at high photometric precision and
cadence. Using observations from the Kilodegree Extremely Little
Telescope (KELT) survey, we identify "dippers," aperiodic and periodic
variables among K2 C13 target stars. This release of the KELT data
provides the community with long-time baseline observations to assist
in the understanding of the more exotic variables in the association.
Transient-like phenomena on timescales of months to years are known
characteristics in the light curves of young stellar objects, making
contextual pre- and post-K2 observations critical to understanding
their underlying processes. We are providing a comprehensive set of
the KELT light curves for known Taurus-Auriga stars in K2 C13. The
combined data sets from K2 and KELT should permit a broad array of
investigations related to star formation, stellar variability, and
protoplanetary environments.
Description:
The Kilodegree Extremely Little Telescope (KELT) survey uses two 42mm
telephoto lenses (KELT-North at Winer Observatory in Arizona in the
United States and KELT-South at the South African Astronomical
Observatory in Sutherland, South Africa). The two telescopes combine
to observe over 70% of the entire sky with a 10-30 minutes cadence.
Each telescope setup provides a 26°x26° field of view and a
23" pixel scale. The typical photometric error for stars 7<V<11 is
∼1%. Both KELT telescopes observe only with a non-standard broad
R-band filter. Therefore, the reported KELT magnitudes in this paper
do not correspond to any standard filter and are only instrumental
magnitudes.
We recommend only using KELT data where the relative flux uncertainty
is <20% rms.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . this file
table1.dat 149 56 Optical broadband magnitudes and kinematics
for each star in our sample
table2.dat 107 56 Infrared and near-IR photometric magnitudes
for all targets in our sample that were
cross-matched to KELT
table3.dat 84 56 The variability and periodicity metrics
for each target as described in Section 4
lcs/* . 56 The KELT light curves -- 56 individual ASCII files
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See also:
B/eso : ESO Science Archive Catalog (ESO, 1991-2018)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
II/328 : AllWISE Data Release (Cutri+ 2013)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/299/89 : COYOTES II (Bouvier+, 1995)
J/A+AS/120/267 : T Tauri stars UBrHalphaz photometry (Osterloh+ 1996)
J/A+A/312/439 : New T Tauri stars in Taurus-Auriga (Wichmann+, 1996)
J/A+A/349/619 : UBVRI light curves of AA Tau in 1995 (Bouvier+, 1999)
J/AJ/117/2941 : Rotation periods of Orion PMS stars (Stassun+, 1999)
J/A+A/379/564 : Vega & PMS stars UBVRI photo-polarimetry (Oudmaijer+ 2001)
J/AJ/124/1001 : JHKs photometry of Cha I variables (Carpenter, 2002)
J/A+A/409/169 : UBVRI light curves of AA Tau in 1999 (Bouvier+, 2003)
J/A+A/463/1017 : B and V light curves of AA Tau (Bouvier+, 2007)
J/A+A/467/785 : SuperWASP/ROSAT periodic variable stars (Norton+, 2007)
J/A+A/479/827 : UBVR light curves of weak-line T Tauri stars (Grankin+, 2008)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/A+A/508/1313 : Orion pre-main sequence RIJH light curves (Frasca+, 2009)
J/A+A/502/883 : I photometry of low mass ONC stars (Rodriguez-Ledesma+, 2009)
J/ApJS/191/389 : Photometric monitoring in σ Ori cluster (Cody+, 2010)
J/AJ/140/2025 : KH 15D (V582 Mon) VI light curves (Herbst+, 2010)
J/ApJS/186/111 : Spitzer observations of Taurus members (Luhman+, 2010)
J/ApJ/733/50 : Mid-IR photom. monitoring of the ONC (Morales-Calderon+, 2011)
J/ApJ/747/51 : Lagoon Nebula stars. I. Rotation periods (Henderson+, 2012)
J/ApJ/745/19 : Binary systems in Taurus-Auriga (Kraus+, 2012)
J/ApJ/745/119 : Close companions to young stars. I. ChaI & Tau (Nguyen+, 2012)
J/ApJ/761/123 : KELT-1 photometry and spectroscopy follow-up (Siverd+, 2012)
J/ApJ/771/129 : Submillimetric Class II sources of Taurus (Andrews+, 2013)
J/A+A/557/A77 : VR light curves of AA Tau in 2007-2013 (Bouvier+, 2013)
J/AJ/146/112 : V light curve of RW Aur (Rodriguez+, 2013)
J/AJ/146/139 : 2010 photometry of variable stars from Dome A (Wang+, 2013)
J/ApJ/784/62 : Circumstellar disks around Taurus binary stars (Akeson+, 2014)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
J/ApJ/784/126 : IR photometry of all known members in Taurus (Esplin+, 2014)
J/ApJ/788/59 : Model for circumstellar disks gas mass (Williams+, 2014)
J/ApJ/799/155 : Sub-stellar companions in Taurus (Daemgen+, 2015)
J/ApJS/216/26 : GALEX search for T Tauri in Tau-Aur (Gomez de Castro+, 2015)
J/AJ/149/50 : Photometry of 105 variable stars from CSTAR (Oelkers+, 2015)
J/AJ/150/32 : KELT 2006-2013 photom. of V409 Tau & AA Tau (Rodriguez+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSSs)
19- 27 I9 --- EPIC [210767482/248180268] EPIC number
29- 39 F11.8 deg RAdeg [65.6/77.1] Right ascension (J2000)
41- 51 F11.8 deg DEdeg [18.8/27.3] Declination (J2000)
53- 58 F6.2 mas/yr pmRA [-11/37] Proper motion along RA
60- 65 F6.2 mas/yr pmDE [-40.4/5] Proper motion along DE
67- 71 F5.2 mag Kpmag [7.8/18.7] Kepler magnitude
73- 78 F6.3 mag u'mag [9.5/24.4]? SDSS-DR12 u' magnitude
80- 84 F5.3 mag e_u'mag [0.001/0.7]? u'mag uncertainty
86- 91 F6.3 mag g'mag [8.3/24.8]? SDSS-DR12 g' magnitude
93- 97 F5.3 mag e_g'mag [0.001/0.6]? g'mag uncertainty
99-104 F6.3 mag r'mag [7.7/22.5]? SDSS-DR12 r' magnitude
106-110 F5.3 mag e_r'mag [0.001/0.2]? r'mag uncertainty
112-117 F6.3 mag i'mag [7.7/21.2]? SDSS-DR12 i' magnitude
119-123 F5.3 mag e_i'mag [0.001/0.07]? i'mag uncertainty
125-130 F6.3 mag z'mag [9.1/21.9]? SDSS-DR12 z' magnitude
132-136 F5.3 mag e_z'mag [0.001/0.4]? z'mag uncertainty
138-143 F6.3 mas Plx [2.5/10.8]? Gaia DR1 parallax
145-149 F5.3 mas e_Plx [0.2/0.5]? Plx uncertainty
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSSs)
19- 24 F6.3 mag Jmag [6.9/14.6]? J-band magnitude (1)
26- 30 F5.3 mag e_Jmag [0.01/0.05]? Jmag uncertainty
32- 37 F6.3 mag Hmag [6.4/13.9]? H-band magnitude (1)
39- 43 F5.3 mag e_Hmag [0.01/0.07]? Hmag uncertainty
45- 50 F6.3 mag Kmag [6.1/13.8]? K-band magnitude (1)
52- 56 F5.3 mag e_Kmag [0.01/0.06]? Kmag uncertainty
58- 63 F6.3 mag W1mag [6/13.5]? AllWISE W1 (3.35um) band magnitude
65- 69 F5.3 mag e_W1mag [0.01/0.2]? W1mag uncertainty
71- 76 F6.3 mag W2mag [5.2/13.4]? AllWISE W2 (4.6um) band magnitude
78- 82 F5.3 mag e_W2mag [0.01/0.1]? W2mag uncertainty
84- 89 F6.3 mag W3mag [2.6/12.1]? AllWISE W3 (11.6um) band magnitude
91- 95 F5.3 mag e_W3mag [0.006/0.5]? W3mag uncertainty
97-101 F5.3 mag W4mag [1.1/9]? AllWISE W4 (22.1um) band magnitude
103-107 F5.3 mag e_W4mag [0.009/0.6]? W4mag uncertainty
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Note (1): From 2MASS, Cutri+ II/246 and Skrutskie+ VII/233
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSSs)
19- 24 F6.3 --- J [0.03/16.9] Stetson J value (2)
26- 31 F6.3 --- L [0.01/11.4] Stetson L value (2)
33- 37 F5.3 --- rms [0.008/1] Magnitude range for 68% of the data
points in each light curve
39- 43 F5.3 --- D90 [0.02/2.8] Δ90 statistic value (7)
45 I1 --- Var [0/1] Variable flag (3)
47 I1 --- Blend [0/1] Blen flag (4)
49- 63 A15 --- Class Classification (5)
65- 70 F6.3 d Per [0.5/45.5]? Period
72- 77 F6.2 --- Pk [3.5/196.5]? Peak power over Simulated power (6)
79- 84 F6.4 mag Amp [0.001/0.3]? Amplitude (7)
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Note (2): We compute the Welch-Stetson J and L statistics
(Stetson 1996PASP..108..851S 1996PASP..108..851S). These statistics are expected to
produce a distribution of values centered at or near zero with a
one-sided tail. Stars in this tail are expected to be variable.
See section 4.1.
Note (3): A star was flagged as a variable if it passed a 2σ cut on the
rms and Δ90 statistic, a 3σ cut on J, and a 5σ cut
on L. See Section 4.1 for a description of how the cuts were
determined.
Note (4): If another star is within 2' and 1.5 magnitude of the target, it is
classified as a blend.
Note (5): Any target classified as N/A did not show a periodic signal or any
variability that would classify it as a dipper or UXor.
Note (6): A measurement of how much larger the Lomb-Scargle peak of the actual
period is versus the maximum peak of the 1000 simulated light curves.
Any period where this ratio is >1 is defined as a real period.
Note (7): For any target classified as N/A, the reported amplitude is the
Δ90 statistic that identifies the magnitude range for 90% of
the data points.
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Byte-by-byte Description of file: lcs/*
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Bytes Format Units Label Explanations
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1- 14 F14.6 d JD Julian Date Terrestrial Time
16- 23 F8.5 mag KELTmag [11.7/21] Apparent KELT magnitude
25- 31 F7.5 mag e_KELTmag [4e-05/1.1] Uncertainty in KELTmag
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Jun-2018