J/A+A/373/576 Detection of Tycho variables stars (Piquard+, 2001)
Variable stars in the Tycho photometric observations: I. Detection.
Piquard S., Halbwachs J.-L., Fabricius C., Geckeler R., Soubiran C.,
Wicenec A.
<Astron. Astrophys. 373, 576 (2001)>
=2001A&A...373..576P 2001A&A...373..576P
ADC_Keywords: Stars, variable ; Magnitudes
Keywords: methods: statistical - stars: variables: general
Abstract:
We present an original way to detect variable stars in the Tycho
photometric observations. A modified Kolmogorov-Smirnov statistical
test has been constructed, based on a model of most of the
satellite's parameters, leading to the dispersion in the
measurements. This allows us to build a treatment taking into account
truncated detections and censored measurements, and to search for
variability in the faint part of the catalogue. The selection
threshold of variable stars has been calibrated to minimize false
alarm rate. Reliable results were thus obtained for stars as faint as
11 mag. One thousand and ninety-one suspected variable stars have
been listed, 407 of which are already known in Hipparcos, GCVS or NSV,
and 684 of which are suspected variable stars to be identified soon.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 123 1091 Candidate variable stars catalogue
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See also:
II/233 : Tycho variables stars (Piquard 2001)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
II/214 : Combined General Catalogue of Variable Stars (Kholopov+ 1998)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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2- 13 A12 --- TYC Tycho designation (Cat. I/239)
15- 26 F12.8 deg RAdeg Tycho right ascension (ICRS, Epoch 1991.25)
28- 39 F12.8 deg DEdeg Tycho declination (ICRS, Epoch 1991.25)
41- 46 I6 --- HIP ?=0 Hipparcos (Cat. I/239) number
48- 53 A6 --- VarType Hipparcos variability type
(P5 field of HIP) (1)
56- 58 I3 --- Nt Number of used detected transits
60- 65 F6.3 mag BTmag Tycho BT magnitude from Tycho-2
(Hoeg et al., 2000, Cat. I/259)
67- 72 F6.3 mag VTmag Tycho VT magnitude from Tycho-2
(Hoeg et al., 2000, Cat. I/259)
75- 83 F9.7 --- tT Probability of a constant star to appear
variable in T channel (2)
86- 94 F9.7 --- t(BT-VT) Probability of a constant star to appear
variable in (BT-VT) (2)
96 I1 --- VarFlag [1,3]? Amplitude flag (H6 field of HIP) (3)
98 A1 --- HvarType [CDMPRU] Period or Unsolved in Hipparcos
(H52 field in HIP) (4)
100 A1 --- GN [GN] Cross identification with GCVS or NSV
102 A1 --- VarType2 [UVW] Variability flag from Tycho
(T48 field) (5)
104 A1 --- Dup [RYZ] Duplicity detection from Tycho
(T49 field) (6)
106 A1 --- An [AB] Flag marking either Annex A or Annex B of
the Tycho Epoch Photometry Annexes
(field T50)
110-118 A9 --- Name GCVS name of the star if existing
121-122 A2 --- Cross Cross-identification flag (7)
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Note (1): This is the 6-letter type defined in the General Catalog of
Variable Stars II/214. See also the "Types of Variability" section
below reproduced from the Hipparcos catalogue.
Note (2): The values are calculated even for stars having less than 10
observations. The calculation of the probability is then uncertain.
Note (3): The values are
1: < 0.06mag ; 2: 0.06-0.6mag ; 3: >0.6mag
Note (4): Hipparcos-defined type of variability (a blank entry signifies that
the entry could not be classified as variable or constant):
C : no variability detected ("constant")
D : duplicity-induced variability
M : possibly micro-variable (amplitude < 0.03mag)
P : periodic variable
R : V-I colour index was revised due to variability analysis
U : unsolved variable which does not fall in the other categories
Note (5): Tycho variability flag:
U : apparent variability in the Tycho data; may be due to duplicity
V : strong evidence of intrinsic variability
W : suspected intrinsic variability
Note (6): Tycho duplicity flag:
D : duplicity clearly indicated (BTmag and VTmag refer to combined light)
R : duplicity weakly indicated, combined with indication of variability
S : duplicity suspected
Y : investigation for duplicity carried out on Tycho data,
no indication of duplicity was found
Z : investigation for duplicity not carried out
blank : Hipparcos star not observed by Tycho
Note (7): Presence in other catalogues:
K : Kazarovets, 1999IBVS.4662....1K 1999IBVS.4662....1K
Ko: Koen and Schumann, 1999MNRAS.310..618K 1999MNRAS.310..618K
R : Rodriguez et al., 2000, Cat. J/A+AS/144/469
S : Schmidt and Seth, 1996, Cat. J/AJ/112/2769
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Types of Variability: (copied from Hipparcos I/239 ReadMe)
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Code Description Class of Variable
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ACV α2 Canum Venaticorum type (including ACVO) rotating
ACYG α Cygni type pulsating
BCEP β Cephei type (including BCEPS) pulsating
BY BY Draconis type rotating
CEP Cepheids (including CEP(B)) pulsating
CST constant stars (considered as variable by
some observer(s)) -
CW W Virginis type pulsating
CWA W Virginis type (periods > 8 days) pulsating
CWB W Virginis type (periods < 8 days) pulsating
DCEP δ Cephei type (including DCEPS) pulsating
DSCT δ Scuti type (including DSCTC) pulsating
E (E+, E/..) eclipsing binary
EA Algol type (EA+, EA/..) eclipsing binary
EB β Lyrae type (EB/..) eclipsing binary
ELL rotating ellipsoidal (ELL+.. or/..) rotating
EW W Ursae Majoris type (EW/i..) eclipsing binary
FKCOM FK Comae Berenices type rotating
GCAS γ Cassiopeiae type eruptive
I irregular (I, IA, IB, In, InT, Is) eruptive
IN irregular (INA, INAT, INB, INSA, INSB, INST, INT) eruptive
IS irregular (ISA, ISB) eruptive
L slow irregular (L, LB, LC) pulsating
M Mira Ceti type pulsating
N slow novae (NB, NC) cataclysmic
NA fast novae cataclysmic
NL nova-like cataclysmic
NR recurrent novae cataclysmic
PVTEL PV Telescopii type pulsating
RCB R Coronae Borealis type eruptive
RR RR Lyrae type (RR, RRAB, RRB, RRC) pulsating
RS RS Canum Venaticorum type eruptive
RV RV Tauri type (RV, RVA, RVB) pulsating
SARV small-amplitude red variables pulsating/rotating
SDOR S Doradus type eruptive
SPB slowly pulsating B stars pulsating
SR semi-regular (SR, SRA, SRB, SRC, SRD) pulsating
SXARI SX Arietis type rotating
SXPHE SX Phoenicis type pulsating
UV UV Ceti type eruptive
WR Wolf-Rayet eruptive
XNG X-ray nova-like system X-ray binary
XP X-ray pulsar X-ray binary
ZAND Z Andromedae type cataclysmic
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Acknowledgements: Sandrine Piquard
(End) Patricia Bauer [CDS] 08-Jun-2001