J/AJ/143/140 BEST-II periodic variables in CoRoT LRa02 field. II. (Fruth+, 2012)
Improved variable star search in large photometric data sets:
new variables in CoRoT field LRa02 detected by BEST II.
Fruth T., Kabath P., Cabrera J., Chini R., Csizmadia Sz., Eigmuller P.,
Erikson A., Kirste S., Lemke R., Murphy M., Pasternacki T., Rauer H.,
Titz-Weider R.
<Astron. J., 143, 140 (2012)>
=2012AJ....143..140F 2012AJ....143..140F
ADC_Keywords: Stars, variable ; Binaries, eclipsing ; Photometry, CCD
Keywords: binaries: eclipsing - methods: data analysis -
stars: variables: general
Abstract:
The CoRoT (Convection, Rotation and planetary Transit) field LRa02 has
been observed with the Berlin Exoplanet Search Telescope II (BEST II)
during the southern summer 2007/2008. A first analysis of stellar
variability led to the publication of 345 newly discovered variable
stars. Now, a deeper analysis of this data set was used to optimize
the variability search procedure. Several methods and parameters have
been tested in order to improve the selection process compared to the
widely used J index for variability ranking. This paper describes an
empirical approach to treat systematic trends in photometric data
based upon the analysis of variance statistics that can significantly
decrease the rate of false detections. Finally, the process of
reanalysis and method improvement has virtually doubled the number of
variable stars compared to the first analysis by Kabath et al.
(Paper I, 2009, Cat. J/A+A/506/569). A supplementary catalog of 272
previously unknown periodic variables plus 52 stars with suspected
variability is presented. Improved ephemerides are given for 19 known
variables in the field. In addition, the BEST II results are compared
with CoRoT data and its automatic variability classification.
Description:
BEST II (Berlin Exoplanet Search Telescope II) is located at the
Observatorio Cerro Armazones, Chile. It is operated by the Institut
fur Planetenforschung of the Deutsches Zentrum fur Luft- und Raumfahrt
in robotic mode from Berlin since summer 2007. The system consists of
a 25cm Baker-Ritchey-Chretien telescope.
The CoRoT long-run field LRa02 was observed by BEST II for 41 nights
from 2007 November to 2008 February prior to the satellite
observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 155 331 Catalog of variable stars detected in CoRoT
field LRa02 after reanalysis of the data set,
sorted by internal BEST II identifiers
table4.dat 155 17 Catalog of periodic variable stars with revised
parameters compared to paper I
(Kabath et al., 2009, Cat. J/A+A/506/569)
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See also:
B/corot : CoRoT observation log Release 12 (CoRoT, 2009-2013)
B/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2013)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
J/AJ/141/166 : HATNet variability survey of K and M dwarfs (Hartman+, 2011)
J/AJ/142/114 : A variable star census in a Perseus field (Pasternacki+, 2011)
J/A+A/506/569 : BEST-II periodic variables in CoRoT LRa02 field (Kabath+, 2009)
J/AJ/137/3911 : BEST periodic variable stars in LRc2 field (Kabath+, 2009)
J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)
J/AJ/136/654 : BEST periodic variable stars in LRa1 field (Kabath+, 2008)
J/AJ/134/1560 : BEST periodic variable stars in IR01 field (Kabath+, 2007)
J/AJ/134/766 : BEST variable stars in LRc1 field (Karoff+, 2007)
http://www.aavso.org/vsx/ : Variable Star Index
Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Field Field name (LRa02a or LRa02b) (1)
8- 12 I5 --- BEST Internal BEST II identifier
14- 16 A3 --- f_BEST Flag on BEST (c, k, s, ck or cs) (2)
18- 34 A17 --- 2MASS 2MASS identifier (3)
36- 37 I2 h RAh [6/6] Hour of Right Ascension (J2000) (4)
39- 40 I2 min RAm [47/55] Minute of Right Ascension (J2000) (4)
42- 45 F4.1 s RAs Second of Right Ascension (J2000) (4)
47 A1 --- DE- Sign of the Declination (J2000) (4)
48- 49 I2 deg DEd [3/6] Degree of Declination (J2000) (4)
51- 52 I2 arcmin DEm Arcminute of Declination (J2000) (4)
54- 57 F4.1 arcsec DEs Arcsecond of Declination (J2000) (4)
59- 63 F5.2 mag RBmag [12.1/18.9] Observed magnitude (5)
65- 71 F7.3 d T0 [34.587/104.975]? Heliocentric Julian Date of
minimum brightness; HJD-2454400 (6)
73- 81 F9.6 d Per [0.07167/41]? Period (6)
83- 90 F8.6 d e_Per ? Uncertainty in Per
92- 96 F5.3 mag Amp ? Amplitude of variability (6)
98-102 F5.3 mag e_Amp ? Uncertainty in Amp
104-110 F7.4 --- Js Stetson's (1996PASP..108..851S 1996PASP..108..851S) J index
of variability
112-118 A7 --- Type Variable type (from B/gcvs) (7)
120-155 A36 --- OName Other names
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Note (1): As the field of view of CoRoT is slightly larger than BEST II, we
split the field into two subfields (called LRa02a and LRa02b,
respectively) and pointed at them alternating.
Note (2): Flag as follows:
c = contaminated light curve due to overlapping aperture
of neighboring stars;
k = known variable (see column "OName" in this table);
s = suspected variable.
Note (3): Of closest 2MASS object within a radius of 2 arcseconds.
Note (4): Derived by an astrometric match of CCD to USNO-A2 coordinates.
Note (5): BEST II observes without any filter to maximize the photon yield
(the CCD sensitivity peaks at 650nm and is roughly comparable to the
Johnson R band).
Note (6): Derived from the analysis of variance algorithm.
Note (7): The newly discovered periodic variable stars are classified by
the shape, amplitude, and period of their folded light curves
according to the scheme used by the General Catalogue of Variable
Stars (Cat. B/gcvs). Types of variable are:
DSCT = Delta Scuti type (pulsating star);
RR = RR Lyrae type (pulsating star);
CEP = Cepheid variables (pulsating star);
EA = Algol type (detached eclipsing binary);
EB = Beta Lyrae type (semidetached eclipsing binary);
EW = W Ursae Majoris type (contact eclipsing binary);
ELL = Stars having sinusoidal-like light curves and showing eclipses
are marked as rotating ellipsoidal variables;
SP = Spotted stars (whose characteristic features are exhibited by
some light curves);
VAR = The type of variability could not be determined from the light
curve alone. Further observations are needed to constrain the
proper physical origin of stellar variability.
LP = Stars that are variable on timescales longer than the
observational baseline are classified as long periodic.
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History:
From electronic version of the journal
References:
Kabath et al. Paper I. 2009A&A...506..569K 2009A&A...506..569K Cat. J/A+A/506/569
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 16-Jul-2013