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

Toby Rodel; Christopher A. Watson; Solène Ulmer-Moll; Samuel Gill; Pierre F.L. Maxted; Sarah L. Casewell; Rafael Brahm; Thomas G. Wilson; Jean C. Costes; Yoshi Nike Emilia Eschen; Lauren Doyle; Alix V. Freckelton; Douglas R. Alves; Ioannis Apergis; Daniel Bayliss; Francois Bouchy; Matthew R. Burleigh; Xavier Dumusque; Jan Eberhardt; Jorge Fernández Fernández; Edward Gillen; Michael R. Goad; Faith Hawthorn; Ravit Helled; Thomas Henning; Katlyn L. Hobbs; James S. Jenkins; Andrés Jordán; Alicia Kendall; Monika Lendl; James McCormac; Ernst J.W. de Mooij; Sean M. O’Brien; Suman Saha; Marcelo Tala Pinto; Trifon Trifonov; Stéphane Udry; Peter J. Wheatley

doi:10.1093/mnras/stae2799

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

Toby Rodel, Christopher A. Watson, Solène Ulmer-Moll, Samuel Gill, Pierre F.L. Maxted, Sarah L. Casewell, Rafael Brahm, Thomas G. Wilson, Jean C. Costes, Yoshi Nike Emilia Eschen, Lauren Doyle, Alix V. Freckelton, Douglas R. Alves, Ioannis Apergis, Daniel Bayliss, Francois Bouchy, Matthew R. Burleigh, Xavier Dumusque, Jan Eberhardt, Jorge Fernández FernándezEdward Gillen, Michael R. Goad, Faith Hawthorn, Ravit Helled, Thomas Henning, Katlyn L. Hobbs, James S. Jenkins, Andrés Jordán, Alicia Kendall, Monika Lendl, James McCormac, Ernst J.W. de Mooij, Sean M. O’Brien, Suman Saha, Marcelo Tala Pinto, Trifon Trifonov, Stéphane Udry, Peter J. Wheatley

Research output: Contribution to journal › Article › peer-review

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 ± 0.006 R_☉, a mass of 0.096⁺₋₀⁰_,^.₀₀₄⁰⁰³ M_☉ and follows a highly eccentric (e = 0.71436 ± 0.00085) orbit every 193.35875 ± 0.00034 d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 M_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.

Original language	English
Pages (from-to)	35-55
Number of pages	21
Journal	Monthly Notices of the Royal Astronomical Society
Volume	537
Issue number	1
DOIs	https://doi.org/10.1093/mnras/stae2799
State	Published - 1 Feb 2025
Externally published	Yes

Keywords

binaries: eclipsing
planets and satellites: detection
planets and satellites: fundamental properties
stars: fundamental properties
stars: late-type
stars: low-mass

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10.1093/mnras/stae2799

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Rodel, T., Watson, C. A., Ulmer-Moll, S., Gill, S., Maxted, P. F. L., Casewell, S. L., Brahm, R., Wilson, T. G., Costes, J. C., Eschen, Y. N. E., Doyle, L., Freckelton, A. V., Alves, D. R., Apergis, I., Bayliss, D., Bouchy, F., Burleigh, M. R., Dumusque, X., Eberhardt, J., ... Wheatley, P. J. (2025). NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary. Monthly Notices of the Royal Astronomical Society, 537(1), 35-55. https://doi.org/10.1093/mnras/stae2799

@article{e555e422d39a4fceab176f6e2aca9346,

title = "NGTS-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 ± 0.006 R☉, a mass of 0.096+−00,.004003 M☉ and follows a highly eccentric (e = 0.71436 ± 0.00085) orbit every 193.35875 ± 0.00034 d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 MJ 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{\textquoteright}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.",

keywords = "binaries: eclipsing, planets and satellites: detection, planets and satellites: fundamental properties, stars: fundamental properties, stars: late-type, stars: low-mass",

author = "Toby Rodel and Watson, {Christopher A.} and Sol{\`e}ne Ulmer-Moll and Samuel Gill and Maxted, {Pierre F.L.} and Casewell, {Sarah L.} and Rafael Brahm and Wilson, {Thomas G.} and Costes, {Jean C.} and Eschen, {Yoshi Nike Emilia} and Lauren Doyle and Freckelton, {Alix V.} and Alves, {Douglas R.} and Ioannis Apergis and Daniel Bayliss and Francois Bouchy and Burleigh, {Matthew R.} and Xavier Dumusque and Jan Eberhardt and Fern{\'a}ndez, {Jorge Fern{\'a}ndez} and Edward Gillen and Goad, {Michael R.} and Faith Hawthorn and Ravit Helled and Thomas Henning and Hobbs, {Katlyn L.} and Jenkins, {James S.} and Andr{\'e}s Jord{\'a}n and Alicia Kendall and Monika Lendl and James McCormac and {de Mooij}, {Ernst J.W.} and O{\textquoteright}Brien, {Sean M.} and Suman Saha and Pinto, {Marcelo Tala} and Trifon Trifonov and St{\'e}phane Udry and Wheatley, {Peter J.}",

note = "Publisher Copyright: {\textcopyright} 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.",

year = "2025",

month = feb,

day = "1",

doi = "10.1093/mnras/stae2799",

language = "English",

volume = "537",

pages = "35--55",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "1",

}

Rodel, T, Watson, CA, Ulmer-Moll, S, Gill, S, Maxted, PFL, Casewell, SL, Brahm, R, Wilson, TG, Costes, JC, Eschen, YNE, Doyle, L, Freckelton, AV, Alves, DR, Apergis, I, Bayliss, D, Bouchy, F, Burleigh, MR, Dumusque, X, Eberhardt, J, Fernández, JF, Gillen, E, Goad, MR, Hawthorn, F, Helled, R, Henning, T, Hobbs, KL, Jenkins, JS, Jordán, A, Kendall, A, Lendl, M, McCormac, J, de Mooij, EJW, O’Brien, SM, Saha, S, Pinto, MT, Trifonov, T, Udry, S & Wheatley, PJ 2025, 'NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary', Monthly Notices of the Royal Astronomical Society, vol. 537, no. 1, pp. 35-55. https://doi.org/10.1093/mnras/stae2799

TY - JOUR

T1 - NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary

AU - Rodel, Toby

AU - Watson, Christopher A.

AU - Ulmer-Moll, Solène

AU - Gill, Samuel

AU - Maxted, Pierre F.L.

AU - Casewell, Sarah L.

AU - Brahm, Rafael

AU - Wilson, Thomas G.

AU - Costes, Jean C.

AU - Eschen, Yoshi Nike Emilia

AU - Doyle, Lauren

AU - Freckelton, Alix V.

AU - Alves, Douglas R.

AU - Apergis, Ioannis

AU - Bayliss, Daniel

AU - Bouchy, Francois

AU - Burleigh, Matthew R.

AU - Dumusque, Xavier

AU - Eberhardt, Jan

AU - Fernández, Jorge Fernández

AU - Gillen, Edward

AU - Goad, Michael R.

AU - Hawthorn, Faith

AU - Helled, Ravit

AU - Henning, Thomas

AU - Hobbs, Katlyn L.

AU - Jenkins, James S.

AU - Jordán, Andrés

AU - Kendall, Alicia

AU - Lendl, Monika

AU - McCormac, James

AU - de Mooij, Ernst J.W.

AU - O’Brien, Sean M.

AU - Saha, Suman

AU - Pinto, Marcelo Tala

AU - Trifonov, Trifon

AU - Udry, Stéphane

AU - Wheatley, Peter J.

PY - 2025/2/1

Y1 - 2025/2/1

N2 - 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 ± 0.006 R☉, a mass of 0.096+−00,.004003 M☉ and follows a highly eccentric (e = 0.71436 ± 0.00085) orbit every 193.35875 ± 0.00034 d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 MJ 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.

AB - 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 ± 0.006 R☉, a mass of 0.096+−00,.004003 M☉ and follows a highly eccentric (e = 0.71436 ± 0.00085) orbit every 193.35875 ± 0.00034 d. This makes NGTS-EB-7 AB the third longest-period eclipsing binary system with a secondary smaller than 200 MJ 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.

KW - binaries: eclipsing

KW - planets and satellites: detection

KW - planets and satellites: fundamental properties

KW - stars: fundamental properties

KW - stars: late-type

KW - stars: low-mass

UR - http://www.scopus.com/inward/record.url?scp=85215413942&partnerID=8YFLogxK

U2 - 10.1093/mnras/stae2799

DO - 10.1093/mnras/stae2799

M3 - Article

AN - SCOPUS:85215413942

SN - 0035-8711

VL - 537

SP - 35

EP - 55

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 1

ER -

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

Abstract

Keywords

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