Abstract
We present the discovery of NGTS J214358.5-380102, an eccentric M-dwarf binary discovered by the Next-Generation Transit Survey (NGTS). The system period of 7.618 d is greater than many known eclipsing M-dwarf binary systems. Its orbital eccentricity of $0.323^{+0.0014}_{-0.0037}$is large relative to the period and semi major axis of the binary. Global modelling of photometry and radial velocities indicates stellar masses of MA = 0.426 ^{+0.0056}_{-0.0049} M⊙,MB = 0.455 ^{+0.0058}_{-0.0052} M⊙ and stellar radii RA = $0.461 ^{+0.038}_{-0.025} R⊙, RB = 0.411 ^{+0.027}_{-0.039} R⊙, respectively. Comparisons with stellar models for low-mass stars show that one star is consistent with model predictions whereas the other is substantially oversized. Spectral analysis of the system suggests a primary of spectral type M3V, consistent with both modelled masses and radii, and with spectral energy distribution fitting of NGTS photometry. As the most eccentric eclipsing M-dwarf binary known, NGTS J214358.5-380102 provides an interesting insight into the strength of tidal effects in the circularization of stellar orbits.
Original language | English |
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Pages (from-to) | 3950-3961 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 494 |
Issue number | 3 |
Early online date | 08 Apr 2020 |
DOIs | |
Publication status | Published - 01 May 2020 |
Keywords
- binaries: eclipsing