More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network

The physical origin of the Blazhko effect (BL), a phenomenon of a single or multiple periodic modulation(s) of the light curve, is under debate. Efficiently identifying and characterizing the BL is essential in understanding its origins and accounting for its effect on numerous applications of RRabs...

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Main Authors: Nan Jiang, Tianrui Sun, Siyuan Pan, Lingzhi Wang, Xue Li, Bin Sheng, Xiaofeng Wang
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Universe
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Online Access:https://www.mdpi.com/2218-1997/11/1/13
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author Nan Jiang
Tianrui Sun
Siyuan Pan
Lingzhi Wang
Xue Li
Bin Sheng
Xiaofeng Wang
author_facet Nan Jiang
Tianrui Sun
Siyuan Pan
Lingzhi Wang
Xue Li
Bin Sheng
Xiaofeng Wang
author_sort Nan Jiang
collection DOAJ
description The physical origin of the Blazhko effect (BL), a phenomenon of a single or multiple periodic modulation(s) of the light curve, is under debate. Efficiently identifying and characterizing the BL is essential in understanding its origins and accounting for its effect on numerous applications of RRabs in the era of large time-domain surveys. In this study, we make use of Resnet 34, a well-known convolutional neural network (CNN) architecture, to identify RRab stars with BL from phased light curves collected from OGLE. Using reliably classified RRabs from frequency analysis to train, validate, and test our model, we show that our CNN method reaches accuracies up to 94%. We then applied our CNN method to some additional RRabs located in the Magellanic Cloud (MC) and the Galactic Bulge (GB), leading to the discovery of 113 and 2496 BL candidates, respectively. The identification accuracy for the MC Sample is estimated to be 91% after cross-matching the CNN classification results with those from frequency analysis. Similarly, the light-curve parameters of these classified BL/non-BL candidates by our CNN method from the GB region resemble those observed in the literature, confirming the reliability of our CNN classifications. Our CNN method is subject to issues related to light-curve quality and sampling, but its overall reliance on light-curve quality is comparable to that of frequency analysis. Furthermore, we find that BL modulation could be primarily characterized by variations in light-curve structure.
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spelling doaj-art-08e88a03a52643bd99e3d2351f1fe8282025-01-24T13:51:29ZengMDPI AGUniverse2218-19972025-01-011111310.3390/universe11010013More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural NetworkNan Jiang0Tianrui Sun1Siyuan Pan2Lingzhi Wang3Xue Li4Bin Sheng5Xiaofeng Wang6David A. Dunlap Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4, Canada Purple Mountain Observatory, CAS, No. 10 Yuanhua Road, Qixia District, Nanjing 210023, ChinaDepartment of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, ChinaChinese Academy of Sciences, South America Center for Astronomy (CASSACA), National Astronomical Observatories, CAS, Beijing 100101, ChinaTsinghua Center for Astrophysics, Physics Department, Tsinghua University, Beijing 100084, ChinaDepartment of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, ChinaTsinghua Center for Astrophysics, Physics Department, Tsinghua University, Beijing 100084, ChinaThe physical origin of the Blazhko effect (BL), a phenomenon of a single or multiple periodic modulation(s) of the light curve, is under debate. Efficiently identifying and characterizing the BL is essential in understanding its origins and accounting for its effect on numerous applications of RRabs in the era of large time-domain surveys. In this study, we make use of Resnet 34, a well-known convolutional neural network (CNN) architecture, to identify RRab stars with BL from phased light curves collected from OGLE. Using reliably classified RRabs from frequency analysis to train, validate, and test our model, we show that our CNN method reaches accuracies up to 94%. We then applied our CNN method to some additional RRabs located in the Magellanic Cloud (MC) and the Galactic Bulge (GB), leading to the discovery of 113 and 2496 BL candidates, respectively. The identification accuracy for the MC Sample is estimated to be 91% after cross-matching the CNN classification results with those from frequency analysis. Similarly, the light-curve parameters of these classified BL/non-BL candidates by our CNN method from the GB region resemble those observed in the literature, confirming the reliability of our CNN classifications. Our CNN method is subject to issues related to light-curve quality and sampling, but its overall reliance on light-curve quality is comparable to that of frequency analysis. Furthermore, we find that BL modulation could be primarily characterized by variations in light-curve structure.https://www.mdpi.com/2218-1997/11/1/13stars: variablesRR Lyrae methodsdata analysis techniquesphotometric
spellingShingle Nan Jiang
Tianrui Sun
Siyuan Pan
Lingzhi Wang
Xue Li
Bin Sheng
Xiaofeng Wang
More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
Universe
stars: variables
RR Lyrae methods
data analysis techniques
photometric
title More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
title_full More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
title_fullStr More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
title_full_unstemmed More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
title_short More Efficient and Reliable: Identifying RRab Stars with Blazhko Effect by Deep Convolutional Neural Network
title_sort more efficient and reliable identifying rrab stars with blazhko effect by deep convolutional neural network
topic stars: variables
RR Lyrae methods
data analysis techniques
photometric
url https://www.mdpi.com/2218-1997/11/1/13
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