C.D.S. - SIMBAD4 rel 1.7 - 2020.07.05CEST05:38:33

2009A&A...506..535S - Astronomy and Astrophysics, volume 506, 535-568 (2009/10-4)

Comparative clustering analysis of variable stars in the Hipparcos, OGLE Large Magellanic Cloud, and CoRoT exoplanet databases.


Abstract (from CDS):

Discovery of new variability classes in large surveys using multivariate statistics techniques such as clustering, relies heavily on the correct understanding of the distribution of known classes as point processes in parameter space. Our objective is to analyze the correspondence between the classical stellar variability types and the clusters found in the distribution of light curve parameters and colour indices of stars in the CoRoT exoplanet sample. The final aim is to help in the identification on new types of variability by first identifying the well known variables in the CoRoT sample. We apply unsupervised classification algorithms to identify clusters of variable stars from modes of the probability density distribution. We use reference variability databases (Hipparcos and OGLE) as a framework to calibrate the clustering methodology. Furthermore, we use the results from supervised classification methods to interpret the resulting clusters. We interpret the clusters in the Hipparcos and OGLE LMC databases in terms of large-amplitude radial pulsators in the classical instability strip and of various types of eclipsing binaries. The Hipparcos data also provide clear distributions for low-amplitude nonradial pulsators. We show that the preselection of targets for the CoRoT exoplanet programme results in a completely different probability density landscape than the OGLE data, the interpretation of which involves mainly classes of low-amplitude variability in main-sequence stars. Our findings will be incorporated to improve the supervised classification used in the CoRoT catalogue production, once the existence of new classes or subtypes will be confirmed from complementary spectroscopic observations.

Abstract Copyright:

Journal keyword(s): methods: statistical - methods: data analysis - stars: binaries: eclipsing - stars: variables: general - stars: statistics - techniques: photometric

Simbad objects: 4

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Number of rows : 4

N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
1 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14826 1
2 OGLE LMC-SC4 323401 Ce* 05 26 28.16 -69 37 59.8           ~ 3 0
3 OGLE LMC-SC3 35239 Ce* 05 27 40.09 -69 56 43.8           ~ 3 0
4 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11533 0

    Equat.    Gal    SGal    Ecl

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