J/MNRAS/358/30 Automated classification of ASAS variables (Eyer+, 2005)
Automated classification of variable stars for All-Sky Automated Survey 1-2
data.
Eyer L., Blake C.
<Mon. Not. R. Astron. Soc., 358, 30-38 (2005)>
=2005MNRAS.358...30E 2005MNRAS.358...30E
ADC_Keywords: Stars, variable ; Photometry
Keywords: astronomical data bases: miscellaneous - catalogues - surveys -
Cepheids - stars: variables: other
Abstract:
With the advent of surveys generating multi-epoch photometry and the
discovery of large numbers of variable stars, the classification of
these stars has to be automatic. We have developed such a
classification procedure for about 1700 stars from the variable star
catalogue of the All-Sky Automated Survey 1-2 (ASAS 1-2) by selecting
the periodic stars and by applying an unsupervised Bayesian classifier
using parameters obtained through a Fourier decomposition of the light
curve. For irregular light curves we used the period and moments of
the magnitude distribution for the classification. In the case of ASAS
1-2, 83 per cent of variable objects are red giants. A general relation
between the period and amplitude is found for a large fraction of
those stars. The selection led to 302 periodic and 1429 semiperiodic
stars, which are classified in six major groups: eclipsing binaries,
'sinusoidal curves', Cepheids, small amplitude red variables, SR and
Mira stars. The type classification error level is estimated to be
about 7 per cent.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 67 302 Results of the classification
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See also:
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-05)
J/AcA/48/35 : All Sky Automated Survey variable stars (Pojmamski 1998)
J/AcA/50/177 : All Sky Automated Survey Catalog (Pojmanski+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- ASAS ASAS Identification (hhmmss-ddmm.m, J2000)
15- 20 F6.3 mag <Imag> Mean I magnitude
22- 26 F5.3 mag e_<Imag> rms uncertainty on <Imag>
28- 31 I4 --- o_<Imag> Number of measurements for <Imag>
33- 40 F8.4 d Per Period
42- 46 F5.3 mag Iamp Amplitude of the variation
48- 52 F5.3 --- R21 Amplitude ratio of harmonic vs fundamental
54- 58 F5.3 rad phi21 Phase difference of harmonic vs fundamental (2)
60 I1 --- nh Number of harmonics
62 I1 --- Class [0/8] Classification code with AUTOCLASS
Bayesian classifier (1)
64- 67 F4.2 --- PMemb Class membership probability
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Note (1): Classification code as follows:
0 = eclipsing binaries of EA and EB type (63 stars)
1 = group composed of difficult cases but of larger amplitude than
the small amplitude group (Class #2) (58 stars)
2 = Small amplitude variables (44 stars)
3 = a large majority are eclipsing binaries, some seem marginal, and
others clearly have a wrong period. (38 stars)
4 = EW-type eclipsing binaries includes very few potential pulsating
stars (such as delta Scuti stars) or Ap stars with very
sinusoidal curves. (36 stars)
5 = Cepheids (32 stars)
6 = Uncertain cases (19 stars)
7 = Long-period variables (8 stars)
8 = RR Lyrae stars (4 stars)
Note (2): phase difference was set in the interval 3π/4 to 3π/4+2π
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Dec-2006