<i>NGTS</i>-EB-7, an eccentric, long-period, low-mass eclipsing binary

ABSTRACT Despite being the most common types of stars in the Galaxy, the physical properties of late M dwarfs are often poorly constrained. A trend of radius inflation compared to evolutionary models has been observed for earlier type M dwarfs in eclipsing binaries, possibly caused by magnetic activity. It is currently unclear whether this trend also extends to later type M dwarfs below the convective boundary. This makes the discovery of lower mass, fully convective, M dwarfs in eclipsing binaries valuable for testing evolutionary models – especially in longer-period binaries where tidal interaction between the primary and secondary is negligible. With this context, we present the discovery of the NGTS-EB-7 AB system, an eclipsing binary containing a late M dwarf secondary and an evolved G-type primary star. The secondary star has a radius of $0.125\pm 0.006$ R$_{\odot }$, a mass of $0.096^{+0.003}_{-0.004}$ M$_{\odot }$ and follows a highly eccentric (e = $0.71436\pm 0.00085$) orbit every $193.35875\pm 0.00034$ d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 ${\rm M}_{\rm J}$ with the mass and radius constrained to better than 5 per cent. In addition, NGTS-EB-7 is situated near the centre of the proposed LOPS2 southern field of the upcoming PLATO mission, allowing for detection of the secondary eclipse and measurement of the companion’s temperature. With its long-period and well-constrained physical properties – NGTS-EB-7 B will make a valuable addition to the sample of M dwarfs in eclipsing binaries and help in determining accurate empirical mass/radius relations for later M dwarf stars.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-12-20
DOI
https://doi.org/10.1093/mnras/stae2799
Citations
4
Primary Topic
Stellar, planetary, and galactic studies
Type
article
Field-Weighted Citation Impact
1.33

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article

NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary

Lauren Doyle, F. Bouchy, J. McCormac, M. R. Burleigh et al.
4 citations
Monthly Notices of the Royal Astronomical Society
Stellar, planetary, and galactic studies
1.33
article

NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary

Lauren Doyle, F. Bouchy, J. McCormac, M. R. Burleigh, Jan Eberhardt, Ravit Helled, Marcelo Tala Pinto, Jorge Fernández Fernández, P. F. L. Maxted, Soléne Ulmer-Moll, M. Lendl, Edward Gillen, Rafael Brahm, Ernst de Mooij, Daniel Bayliss, M. R. Goad, Alicia Kendall, S. L. Casewell, Samuel Gill, J. S. Jenkins, K. Hobbs, P. J. Wheatley, Sean O'Brien, Andrés Jordán, Faith Hawthorn, Jean C Costes, C. A. Watson, Trifon Trifonov, Suman Saha, X. Dumusque, T. G. Wilson, S. Udry, Toby Rodel, Alix Violet Freckelton, Ioannis Apergis, Yoshi Nike Emilia Eschen, D. R. Alves, Thomas Henning
article en
4 citations

Abstract

ABSTRACT Despite being the most common types of stars in the Galaxy, the physical properties of late M dwarfs are often poorly constrained. A trend of radius inflation compared to evolutionary models has been observed for earlier type M dwarfs in eclipsing binaries, possibly caused by magnetic activity. It is currently unclear whether this trend also extends to later type M dwarfs below the convective boundary. This makes the discovery of lower mass, fully convective, M dwarfs in eclipsing binaries valuable for testing evolutionary models – especially in longer-period binaries where tidal interaction between the primary and secondary is negligible. With this context, we present the discovery of the NGTS-EB-7 AB system, an eclipsing binary containing a late M dwarf secondary and an evolved G-type primary star. The secondary star has a radius of $0.125\pm 0.006$ R$_{\odot }$, a mass of $0.096^{+0.003}_{-0.004}$ M$_{\odot }$ and follows a highly eccentric (e = $0.71436\pm 0.00085$) orbit every $193.35875\pm 0.00034$ d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 ${\rm M}_{\rm J}$ with the mass and radius constrained to better than 5 per cent. In addition, NGTS-EB-7 is situated near the centre of the proposed LOPS2 southern field of the upcoming PLATO mission, allowing for detection of the secondary eclipse and measurement of the companion’s temperature. With its long-period and well-constrained physical properties – NGTS-EB-7 B will make a valuable addition to the sample of M dwarfs in eclipsing binaries and help in determining accurate empirical mass/radius relations for later M dwarf stars.

Monthly Notices of the Royal Astronomical SocietyVol. 537(1)
University of Geneva (CH), University of Bern (CH), Queen's University Belfast (GB), University of Leicester (GB), Queen Mary University of London (GB), ZHAW Zurich University of Applied Sciences (CH), University of Zurich (CH), Adolfo Ibáñez University (CL), Heidelberg University (DE), University of Warwick (GB), Millennium Institute of Astrophysics (CL), Max Planck Institute for Astronomy (DE), Data Observatory Foundation, Keele University (GB), Sofia University "St. Kliment Ohridski" (BG), University of Chile (CL), University of Birmingham (GB), International Space Science Institute (CH), Universidad Diego Portales (CL)
National Science Foundation, National Aeronautics and Space Administration, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Agencia Nacional de Investigación y Desarrollo, Ames Research Center, Science and Technology Facilities Council, Fondo Nacional de Desarrollo Científico y Tecnológico
Life below water
Openalex Percentile: Top 19%
Stellar, planetary, and galactic studies
1.33
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