II/233 Tycho variables stars (Piquard 2001)
Detection and classification of Tycho variables stars
Piquard S.
<PhD Dissertation, Strasbourg, (2001)>
ADC_Keywords: Stars, variable ; Magnitudes
Description:
We present the results of the classification procedure described in
Piquard's PhD thesis applied to the 1091 stars presented in Piquard et
al. (2001. Cat. J/A+A/373/576). In those six tables we give
indication of variability type for all the stars detected as variables
in Piquard et al. (2001, Cat. J/A+A/373/576). First of all, we
looked for periodic signals in the light curves using adapted Renson's
(Renson, 1978A&A....63..125R 1978A&A....63..125R) and Stellingwerf's (Stellingwerf,
1978ApJ...224..953S 1978ApJ...224..953S) methods applied to the tree different photometric
bands from Tycho (Cat. I/239): T, BT, VT (the T band is defined
from the added count-rates in the BT and VT channels, Grossmann et
al.. 1995A&A...304..110G 1995A&A...304..110G). Then we developed a semi-automatic method
using 5 parameters (Period, color index, reduced proper motion from
Tycho-2 catalogue (Cat. I/259), 2 indicators of the shape of the
light curve) and a maximum likelihood method, combined with a careful
look on the light curves. Finaly, the identification of the
variability type is kept only if the resulting light curve is
convincing (periodic the star has the P status, if not periodic the
star has the U status); else we need more information about the star
and is has the A status. All this identifications are indications
since the quality of the light curves are often poor, particularly
when the star is fainter than T=10.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablet.dat 174 954 Stars detected as variable in T
tableb-v.dat 174 107 Stars detected as variable in BT-VT
thesis.ps 132 391718 PostScript version of the thesis
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See also:
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)
J/A+A/373/576 : Detection of Tycho variables stars (Piquard+, 2001)
Byte-by-byte Description of file: tablet.dat tableb-v.dat
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Bytes Format Units Label Explanations
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1 A1 --- Status [PUA] Status of the star (1)
4- 15 A12 --- TYC Tycho designation (Cat. I/239)
17- 28 F12.8 deg RAdeg Tycho right ascension (ICRS, Epoch 1991.25)
30- 41 F12.8 deg DEdeg Tycho declination (ICRS, Epoch 1991.25)
43- 48 I6 --- HIP ?=0 Hipparcos (Cat. I/239) number
50- 55 A6 --- VarType Hipparcos variability type
(P5 field of HIP) (2)
58- 60 I3 --- Nt Number of used detected transits
62- 67 F6.3 mag BTmag Tycho BT magnitude from Tycho-2
(Hoeg et al., 2000, Cat. I/259)
69- 74 F6.3 mag VTmag Tycho VT magnitude from Tycho-2
(Hoeg et al., 2000, Cat. I/259)
77- 85 F9.7 --- tT [0,1] Probability of a constant star to appear
variable in T magnitude (3)
88- 96 F9.7 --- t(BT-VT) [0,1] Probability of a constant star to appear
variable in (BT-VT) (3)
98 I1 --- VarFlag [1,3]? Amplitude flag (H6 field of HIP) (4)
100 A1 --- HvarType [CDMPRU] Period or Unsolved in Hipparcos
(H52 field in HIP) (5)
102 A1 --- GN [GN] Cross identification with GCVS or NSV
104 A1 --- VarType2 [UVW] Variability flag from Tycho
(T48 field) (6)
106 A1 --- Dup [RYZ] Duplicity detection from Tycho
(T49 field) (7)
108 A1 --- An [AB] Flag marking either Annex A or Annex B of
the Tycho Epoch Photometry Annexes (field T50)
112-120 A9 --- Name GCVS name of the star if existing
122-126 F5.3 d PerOld Known period
128-135 A8 --- SpType Spectral type from Simbad
137-147 F11.6 d Period Best period found
150-154 F5.3 d Ampl Amplitude of the light curve after best fit
157-161 F5.3 --- Dur Duration of the light curve after best fit
(in phase unit)
163 A1 --- --- [APU] Status (repeated) (1)
165-172 A8 --- Type This work type of variability
(ech: inadequate time sampling suspected)
174 A1 --- New [*] *: New variable
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Note (1): Status of the stars:
P: Stars found to be periodic
U: Stars with no period found
A: Stars needing more observations
Note (2): This is the 6-letter type defined in the General Catalog of Variable
Stars (Cat. II/214). See also the "Types of Variability" section
below reproduced from the Hipparcos catalogue.
Note (3): The values are calculated even for stars having less than 10
observations. The calculation of the probability is then uncertain.
Note (4): The values are
1: < 0.06mag ; 2: 0.06-0.6mag ; 3: >0.6mag
Note (5): 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 (6): 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 (7): 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
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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] 09-Nov-2001