2022A&A...666A..76A


Query : 2022A&A...666A..76A

2022A&A...666A..76A - Astronomy and Astrophysics, volume 666A, 76 (2022/10-1)

Multiscale entropy analysis of astronomical time series Discovering subclusters of hybrid pulsators.

AUDENAERT J. and TKACHENKO A.

Abstract (from CDS):


Context. The multiscale entropy assesses the complexity of a signal across different timescales. It originates from the biomedical domain and was recently successfully used to characterize light curves as part of a supervised machine learning framework to classify stellar variability.
Aims. We aim to explore the behavior of the multiscale entropy in detail by studying its algorithmic properties in a stellar variability context and by linking it with traditional astronomical time series analysis methods and metrics such as the Lomb-Scargle periodogram. We subsequently use the multiscale entropy as the basis for an interpretable clustering framework that can distinguish hybrid pulsators with both p- and g-modes from stars with only p-mode pulsations, such as δ Scuti (δ Sct) stars, or from stars with only g-mode pulsations, such as γ Doradus (γ Dor) stars.
Methods. We calculate the multiscale entropy for a set of Kepler light curves and simulated sine waves. We link the multiscale entropy to the type of stellar variability and to the frequency content of a signal through a correlation analysis and a set of simulations. The dimensionality of the multiscale entropy is reduced to two dimensions and is subsequently used as input to the HDBSCAN density-based clustering algorithm in order to find the hybrid pulsators within sets of δ Sct and γ Dor stars that were observed by Kepler.
Results. We find that the multiscale entropy is a powerful tool for capturing variability patterns in stellar light curves. The multiscale entropy provides insights into the pulsation structure of a star and reveals how short- and long-term variability interact with each other based on time-domain information only. We also show that the multiscale entropy is correlated to the frequency content of a stellar signal and in particular to the near-core rotation rates of g-mode pulsators. We find that our new clustering framework can successfully identify the hybrid pulsators with both p- and g-modes in sets of δ Sct and γ Dor stars, respectively. The benefit of our clustering framework is that it is unsupervised. It therefore does not require previously labeled data and hence is not biased by previous knowledge.

Abstract Copyright: © J. Audenaert and A. Tkachenko 2022

Journal keyword(s): asteroseismology - methods: data analysis - methods: observational - methods: statistical - techniques: photometric

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 2MASS J19272731+3829199 Ro* 19 27 27.3209100720 +38 29 19.934187360           ~ 7 0
2 Cl* NGC 6811 SAN 147 gD* 19 37 25.2380114270 +46 19 35.587893758   12.62 12.255   11.79 ~ 20 0
3 TYC 3141-3425-1 dS* 19 52 43.8555165192 +40 10 56.008622892   11.78 11.54     F1V 12 0

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