University of Leicester
Browse

Classifying Exoplanet Candidates with Convolutional Neural Networks: Application to the Next Generation Transit Survey

Download (12.09 MB)
journal contribution
posted on 2020-11-06, 16:01 authored by A Chaushev, L Raynard, MR Goad, P Eigmüller, DJ Armstrong, JT Briegal, MR Burleigh, SL Casewell, S Gill, JS Jenkins, LD Nielsen, CA Watson, RG West, PJ Wheatley, S Udry, JI Vines
Vetting of exoplanet candidates in transit surveys is a manual process, which suffers from a large number of false positives and a lack of consistency. Previous work has shown that convolutional neural networks (CNN) provide an efficient solution to these problems. Here, we apply a CNN to classify planet candidates from the Next Generation Transit Survey (NGTS). For training data sets we compare both real data with injected planetary transits and fully simulated data, as well as how their different compositions affect network performance. We show that fewer hand labelled light curves can be utilized, while still achieving competitive results. With our best model, we achieve an area under the curve (AUC) score of (95.6±0.2) per cent and an accuracy of (88.5±0.3) per cent on our unseen test data, as well as (76.5±0.4) per cent and (74.6±1.1) per cent in comparison to our existing manual classifications. The neural network recovers 13 out of 14 confirmed planets observed by NGTS, with high probability. We use simulated data to show that the overall network performance is resilient to mislabelling of the training data set, a problem that might arise due to unidentified, low signal-to-noise transits. Using a CNN, the time required for vetting can be reduced by half, while still recovering the vast majority of manually flagged candidates. In addition, we identify many new candidates with high probabilities which were not flagged by human vetters.

Funding

Based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS facility is operated by the consortium institutes with support from the UK Science and Technology Facilities Council (STFC) through projects ST/M001962/1 and ST/S002642/1. LR is supported by an STFC studentship (1795021). The contributions at the University of Leicester by MRG and MRB have been supported by STFC through consolidated grant ST/N000757/1. PE and ACh acknowledge the support of the DFG priority program SPP 1992 ”Exploring the Diversity of Extrasolar Planets” (RA 714/13-1). The contributions at the University of Warwick by PJW and RGW have been supported by STFC through consolidated grants ST/L000733/1 and ST/P000495/1. DJA gratefully acknowledges support from the STFC via an Ernest Rutherford Fellowship (ST/R00384X/1). JSJ acknowledges support by Fondecyt grant 1161218 and partial support by CATA-Basal (PB06, CONICYT). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research used the ALICE High Performance Computing Facility at the University of Leicester.

History

Citation

Monthly Notices of the Royal Astronomical Society, Volume 488, Issue 4, October 2019, Pages 5232–5250, https://doi.org/10.1093/mnras/stz2058

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

  • VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Volume

488

Issue

4

Pagination

5232-5250

Publisher

Oxford University Press (OUP), Royal Astronomical Society

eissn

1365-2966

Copyright date

2019

Available date

2019-07-31

Notes

The file associated with this record is under embargo until publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

Usage metrics

    University of Leicester Publications

    Categories

    No categories selected

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC