Application of convolutional neural networks for stellar spectral classification

Journal Article · Wed Nov 06 00:00:00 EST 2019 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stz3100· OSTI ID:1706198

Sharma, Kaushal  ^[1]; Kembhavi, Ajit ^[1]; Kembhavi, Aniruddha ^[2]; Sivarani, T. ^[3]; Abraham, Sheelu ^[4]; Vaghmare, Kaustubh ^[1]

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1. Inter University Centre for Astronomy and Astrophysics, Pune 411007, India
2. PRIOR, Allen Institute for Artificial Intelligence, Seattle 98103, USA, Department of Computer Science and Engineering, University of Washington, Seattle 98195, USA
3. Indian Institute of Astrophysics, Koramangala, Bengaluru 560034, India
4. Department of Physics, Mar Thoma College, Chungathara 679334, Nilambur, India

ABSTRACT Due to the ever-expanding volume of observed spectroscopic data from surveys such as SDSS and LAMOST, it has become important to apply artificial intelligence (AI) techniques for analysing stellar spectra to solve spectral classification and regression problems like the determination of stellar atmospheric parameters Teff, $$\rm {\log g}$$, and [Fe/H]. We propose an automated approach for the classification of stellar spectra in the optical region using convolutional neural networks (CNNs). Traditional machine learning (ML) methods with ‘shallow’ architecture (usually up to two hidden layers) have been trained for these purposes in the past. However, deep learning methods with a larger number of hidden layers allow the use of finer details in the spectrum which results in improved accuracy and better generalization. Studying finer spectral signatures also enables us to determine accurate differential stellar parameters and find rare objects. We examine various machine and deep learning algorithms like artificial neural networks, Random Forest, and CNN to classify stellar spectra using the Jacoby Atlas, ELODIE, and MILES spectral libraries as training samples. We test the performance of the trained networks on the Indo-U.S. Library of Coudé Feed Stellar Spectra (CFLIB). We show that using CNNs, we are able to lower the error up to 1.23 spectral subclasses as compared to that of two subclasses achieved in the past studies with ML approach. We further apply the trained model to classify stellar spectra retrieved from the SDSS data base with SNR > 20.

• Sponsoring Organization: USDOE
• OSTI ID: 1706198
• Journal Information: Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Vol. 491 Journal Issue: 2; ISSN 0035-8711
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English