posted on 2019-09-13, 09:51authored bySL Casewell, L Raynard, CA Watson, E Gillen, E de Mooij, D Bayliss, F Bouchy, A Thompson, JAG Jackman, MR Burleigh, A Chaushev, C Belardi, T Louden, MR Goad, LD Nielsen, K Poppenhaeger, P Eigmueller, MN Gunther, JS Jenkins, J McCormac, M Moyano, D Queloz, AMS Smith, RG West, PJ Wheatley
We have discovered a new, near-equal-mass, eclipsing M dwarf binary from the Next Generation Transit Survey. This system is only one of three field-age (>1 Gyr), late M dwarf
eclipsing binaries known, and has a period of 1.74774 d, similar to that of CM Dra and
KOI126. Modelling of the eclipses and radial velocities shows that the component masses
are Mpri =0.17391+0.00153 −0.00099 M, Msec = 0.17418+0.00193
−0.00059 M; and the radii are Rpri =
0.2045+0.0038
−0.0058 R, Rsec = 0.2168+0.0047 −0.0048 R. The effective temperatures are Tpri = 2995 +85
−105 K
and Tsec = 2997 +66
−101K, consistent with M5 dwarfs and broadly consistent with main-sequence
models. This pair represents a valuable addition that can be used to constrain the mass–radius
relationship at the low-mass end of the stellar sequence.
Funding
This publication is based on data collected under the NGTS project at the ESO La Silla Paranal Observatory. The NGTS instrument and operations are funded by the consortium institutes and by the UK Science and Technology Facilities Council (STFC; project reference ST/M001962/1). The WHT and its service program are operated on the island of La Palma by the Isaac Newton Group of Telescopes in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. This paper also uses observations made at the South African Astronomical Observatory (SAAO). SLC acknowledges support from LISEO at the University of Leicester. EG acknowledges support from the Winton foundation. MRG and MRB are supported by an STFC consolidated grant (ST/N000757/1). PJW, RGW and TL are supported by an STFC consolidated grant (ST/P000495/1). JSJ acknowledges support by FONDECYT grant 1161218 and partial support by CATA-Basal (PB06, CONICYT). This work utilizes the ELLC exoplanet and binary star model developed by P. F. L. Maxted, and we thank him for his specific recommendations for using this model.
History
Citation
Monthly Notices of the Royal Astronomical Society, 2018, 481 (2), pp. 1897-1907 (11)
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
Publisher
Oxford University Press (OUP), Royal Astronomical Society