The EBLM Project IV. Spectroscopic orbits of over 100 eclipsing M dwarfs masquerading as transiting hot-Jupiters

Abstract

We present 2271 radial velocity measurements taken on 118 single-line binary stars, taken over eight years with the CORALIE spectrograph. The binaries consist of F/G/K primaries and M-dwarf secondaries. They were initially discovered photometrically by the WASP planet survey, as their shallow eclipses mimic a hot-Jupiter transit. The observations we present permit a precise characterisation of the binary orbital elements and mass function. With modelling of the primary star this mass function is converted to a mass of the secondary star. In the future, this spectroscopic work will be combined with precise photometric eclipses to draw an empirical mass/radius relation for the bottom of the mass sequence. This has applications in both stellar astrophysics and the growing number of exoplanet surveys around M-dwarfs. In particular, we have discovered 34 systems with a secondary mass below $0.2M_{\odot }$, and so we will ultimately double the known number of very low-mass stars with well characterised mass and radii. We are able to detect eccentricities as small as 0.001 and orbital periods to sub-second precision. Our sample can revisit some earlier work on the tidal evolution of close binaries, extending it to low mass ratios. We find some binaries that are eccentric at orbital periods < 3 days, while our longest circular orbit has a period of 10.4 days. By collating the EBLM binaries with published WASP planets and brown dwarfs, we derive a mass spectrum with twice the resolution of previous work. We compare the WASP/EBLM sample of tightly-bound orbits with work in the literature on more distant companions up to 10 AU. We note that the brown dwarf desert appears wider, as it carves into the planetary domain for our short-period orbits. This would mean that a significantly reduced abundance of planets begins at $\sim 3M_{\mathrm{Jup}}$, well before the Deuterium-burning limit. [abridged]

14 pages, 12 figures, 7 Tables. Under review at A&A, corrections after comments by the referee

References in corpus (26)

• The Dartmouth Stellar Evolution Database
• The K2 Mission: Characterization and Early results
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• Tertiary companions to close spectroscopic binaries
• Efficient identification of exoplanetary transit candidates from SuperWASP light curves
• A new list of thorium and argon spectral lines in the visible
• A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host
• Weighing The Non-Transiting Hot Jupiter Tau BOO b
• The HARPS search for southern extra-solar planets XIX. Characterization and dynamics of the GJ876 planetary system
• WASP-4b: a 12th-magnitude transiting hot-Jupiter in the Southern hemisphere
• WASP-80b has a dayside within the T-dwarf range
• On the tidal origin of hot Jupiter stellar obliquity trends
• WIYN Open Cluster Study. LX. Spectroscopic Binary Orbits in NGC 6819
• The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets
• The SDSS-2MASS-WISE Ten Dimensional Stellar Color Locus
• The GAPS Programme with HARPS-N at TNG. III: The retrograde orbit of HAT-P-18b
• Eccentricity and Spin-Orbit Misalignment in Short-Period Stellar Binaries as a Signpost of Hidden Tertiary Companions
• WASP-94 A and B planets: hot-Jupiter cousins in a twin-star system
• The BANANA project. V. Misaligned and precessing stellar rotation axes in CV Velorum
• First limits on the occurrence rate of short-period planets orbiting brown dwarfs
• The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit
• WASP-117b: a 10-day-period Saturn in an eccentric and misaligned orbit
• Rossiter-McLaughlin Observations of 55 Cnc e
• The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP

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