J/ApJS/175/191 Variables from 2MASS calibration fields (Plavchan+, 2008)
Near-infrared variability in the 2MASS calibration fields: a search for
planetary transit candidates.
Plavchan P., Jura M., Kirkpatrick J.D., Cutri R.M., Gallagher S.C.
<Astrophys. J. Suppl. Ser., 175, 191-228 (2008)>
=2008ApJS..175..191P 2008ApJS..175..191P
ADC_Keywords: Stars, variable ; Photometry, infrared
Keywords: binaries: eclipsing - methods: statistical - stars: variables: other
Abstract:
The Two Micron All Sky Survey (2MASS) photometric calibration
observations cover ∼6 square degrees on the sky in 35 "calibration
fields", each sampled in nominal photometric conditions between 562
and 3692 times during the 4 years of the 2MASS mission. We compile a
catalog of variables from the calibration observations to search for
M dwarfs transited by extrasolar planets. We present our methods for
measuring periodic and nonperiodic flux variability. From 7554 sources
with apparent Ks magnitudes between 5.6 and 16.1, we identify 247
variables, including extragalactic variables and 23 periodic
variables. We have discovered three M dwarf eclipsing systems,
including two candidates for transiting extrasolar planets.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 72 7554 Sample Properties
table4.dat 97 247 Variables
table5.dat 97 58 Candidate Variables
table8.dat 81 23 Periodic Variables
table13.dat 95 247 Classification of Variables
table14.dat 95 58 Classification of Candidate Variables
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See also:
V/121 : Catalog of DMS-type eclipsing binaries (Svechnikov+, 1999)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/380/590 : 30 DENIS late-M dwarfs between 15 and 30pc (Phan-Bao+, 2001)
J/A+A/390/267 : The CORALIE survey for extrasolar planets VIII (Udry+, 2002)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS PSC source identification (HHMMSSss+DDMMSSs) (1)
18- 22 I5 --- Field Field number
24- 27 I4 --- Ndet Number of detections (2)
29- 35 F7.4 mag Jmag 2MASS J band magnitude (3)
37- 42 F6.4 mag e_Jmag Uncertainty in Jmag
44- 50 F7.4 mag Hmag 2MASS H band magnitude (3)
52- 57 F6.4 mag e_Hmag Uncertainty in Hmag
59- 65 F7.4 mag Ksmag 2MASS Ks band magnitude (3)
67- 72 F6.4 mag e_Ksmag Uncertainty in Ksmag
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Note (1): We note that all Cal-PSWDB detections have unique identifiers,
and we spatially associate each with the PSC catalog source and
designation in our sample (Section 2.2).
Note (2): Either in J, H or Ks (equivalent to Nm,n in text).
See Table 1 and Section 3.1 for discussion.
Note (3): Unweighted mean apparent magnitude of Cal-PSWDB photometry
(equivalent to mn in text).
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Byte-by-byte Description of file: table[45].dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS PSC source identification (HHMMSSss+DDMMSSs)
18- 19 I2 % Prob ? Probability of intrinsic variability (1)
21 I1 --- o_Flags Number of Flags
23- 29 I07 --- Flags Variability flags (G1)
31 A1 --- l_Jflm The 3σ limit flag on Jflm
32- 37 F6.4 mag Jflm 2MASS J band flicker magnitude (2)
39- 44 F6.4 mag e_Jflm ? Uncertainty in Jflm
46 A1 --- l_Hflm The 3σ limit flag on Hflm
47- 52 F6.4 mag Hflm 2MASS H band flicker magnitude (2)
54- 59 F6.4 mag e_Hflm ? Uncertainty in Hflm
61 A1 --- l_Ksflm The 3σ limit flag on Ksflm
62- 68 F7.4 mag Ksflm 2MASS Ks band flicker magnitude (2)
70- 75 F6.4 mag e_Ksflm ? Uncertainty in Ksflm
77- 80 I4 --- neJ ? 2MASS J band excursion number (3)
82- 85 I4 --- neH ? 2MASS H band excursion number (3)
87- 90 I4 --- neKs ? 2MASS Ks band excursion number (3)
92- 97 F6.3 --- S-Ind Stetson Index (4)
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Note (1): For Table 5, estimated probability that the observed variability
is intrinsic to the source, rather than due to seeing variations.
See Section 3.3.1 for discussion.
Note (2): Magnitudes of "flickering" variability for flags 1-3. 3σ
upper-limits and detections are listed, but 5σ is required
to trigger the variability flags. See Section 3.2.1.
Note (3): The number of excursions for flags 4-6. The "excursive" scan groups
need not be the same between bands. A positive number corresponds to
the largest excursion being fainter than the mean magnitude, and
vice-versa for a negative number. See Section 3.2.2.
Note (4): A Stetson Index in excess of 0.2 triggers the Stetson variability
flag. See Section 3.2.3.
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Byte-by-byte Description of file: table8.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS 2MASS-PSC Name (HHMMSSss+DDMMSSs)
18- 24 I07 --- Flags Variability flags (G1)
26- 33 F8.6 d Per Period (1)
35 A1 --- f_Per [eg] Note on the period (2)
37- 43 F7.5 d Per2 ? 2d Period for eclipsing binary (3)
45- 49 F5.3 --- Phase Phase (4)
51- 55 I5 --- Field Field
57- 79 A23 --- Type Object Type (5)
81 A1 --- f_Type [f] Flag on object type (6)
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Note (1): Uncertainty in period is approximately ±1 in the
least significant digit.
Note (2): Flag as follows:
e = Period from A. Becker
g = The identification of this period is uncertain. The object exhibits
variability on a 3 day timescale, but the observed variability is
not entirely consistent with this period derived from our analysis.
Note (3): When two periods are quoted, the system is an eclipsing binary
with indistinguishable eclipses or an inconclusive object type.
See Figs. 22-44 for light curves and 45-67 for color curves of
these objects folded to these periods.
Note (4): Corresponding phase in Figs. 22-67 for the Julian Date=2450000.0.
When two periods are listed, this phase is for the larger period,
which is also the one plotted in Figs. 33, 34, and 38.
Note (5): Object type inferred from period, colors, light curve appearance, and
Galactic latitude. Sinusoidal objects and objects without any listed
object type have inconclusive identifications from available data.
Note (6): See Section 4.2.1 for discussion of these object (newly discovered
detached eclipsing binaries with M dwarf components).
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Byte-by-byte Description of file: table1[34].dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- 2MASS PSC source identification (HHMMSSss+DDMMSSs)
18- 23 F6.3 mag Ksmag 2MASS Ks band magnitude
25- 29 F5.2 mag B-Ks ? The (B-Ks) color index
31- 36 F6.3 mag H-Ks The 2MASS (H-Ks) color index
38- 42 F5.3 mag J-H The 2MASS (J-H) color index
44 A1 --- Cat Color category (1)
46- 95 A50 --- Note Note on Name (2)
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Note (1): Categories "A","B","C","D","E" and "F" corresponds to sources in
|b|>20 fields as follows:
A = sources with B-Ks<4.97 and H-Ks<0.2;
B = sources with B-Ks<4.97 and 0.2<H-Ks<0.7;
C = B-Ks<4.97 and H-Ks>0.8;
D = B-Ks>4.97, excluding category "F" sources;
E = sources have no identified B counterpart and typically H-Ks>0.2;
F = sources have colors consistent with evolved giants.
See Figures 68 and 69, and Section 4.3.
G = sources in |b|<20° fields.
Note (2): This column lists such information as any SIMBAD object
identification, any SDSS DR5 object identification (e.g. "STAR"),
any coincident extragalactic source name, a period if the source is
periodic, and the type of object if a reasonable determination can
be made (e.g. "eclipsing binary"). This list is not complete.
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Global notes:
Note (G1): The seven variability "flags" are defined in Section 3.2;
each of the seven flags takes the value 1 for a variability
identified for this flag, and 0 otherwise. The meaning of the
flags are, from left to right:
[1-3] = >5σ flickering in J, H and Ks: the standard deviation of
the source variability that reproduces the observed photometric
scatter in excess of the expected photometric scatter
(equivalent to σvar,m,n±νvar,m,n in the text).
[4-6] = the number of excursions in J, H and Ks: individual scan
groups that are >5σ deviant from the mean magnitude.
7 = variables with Stetson indices in excess of 0.2.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 17-Jun-2009