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Short-period gas giant planets have been shown to be significantly rarer for host stars less massive than the Sun. We report the discovery of two transiting giant planets – TOI-2379 b and TOI-2384 b – with low-mass (early M) host stars. Both planets were detected using Transiting Exoplanet Survey Satellite photometry and for both the transit signal was validated using ground-based photometric facilities. We confirm the planetary nature of these companions and measure their masses using radial velocity observations. We find that TOI-2379 b has an orbital period of 5.469 d and a mass and radius of |$5.76\pm 0.20$|  M |$_{J}$| and |$1.046\pm 0.023$|  R |$_{J}$| and TOI-2384 b has an orbital period of 2.136 d and a mass and radius of |$1.966\pm 0.059$|  M |$_{J}$| and |$1.025\pm 0.021$|  R |$_{J}$|⁠. TOI-2379 b and TOI-2384 b have the highest and third highest planet-to-star mass ratios, respectively, out of all transiting exoplanets with a low-mass host star, placing them uniquely among the population of known exoplanets and making them highly important pieces of the puzzle for understanding the extremes of giant planet formation. [ABSTRACT FROM AUTHOR]

We report the discovery of a relatively bright eclipsing binary system, which consists of a white dwarf (WD) and a main-sequence K7 star with clear signs of chromospheric and spot activity. The light curve of this system shows ∼0.2 mag ellipsoidal variability with a period of 0.297549 d and a short total eclipse of the WD. Based on our analysis of the spectral and photometric data, we estimated the parameters of the system. The K7V star is tidally deformed but does not fill its Roche lobe (the filling factor is about 0.86). The orbital inclination is i  = |$73{_{.}^{\circ}}1 \pm 0{_{.}^{\circ}}2$|⁠ , and the mass ratio is q  = M 2/ M 1 ≈ 0.88. The parameters of the K7V star are M 2 ≈ 0.64 M⊙, R 2 = 0.645 ± 0.012 R ⊙, and T 2 ≈ 4070 K. The parameters of the WD are M 1 ≈ 0.72 M⊙, R 1 = 0.013 ± 0.003 R ⊙, and T 1 = 8700 ± 1100 K. Photometric observations in different bands revealed that the maximum depth of the eclipse is in the SDSS r filter, which is unusual for a system of a WD and a late main-sequence star. We suspect that this system is a product of the evolution of a common-envelope binary star, and that the WD accretes the stellar wind from the secondary star (the so-called low-accretion-rate polar, hereafter LARP). [ABSTRACT FROM AUTHOR]

We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-min cadence Transiting Exoplanet Survey Satellite (TESS) photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE), and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a |$1.254\pm 0.016\ \rm {R}_ \rm{J}$|⁠ , massive (⁠|$2.61^{+0.19}_{-0.12}\ \rm {M}_ \rm{J}$|⁠) hot Jupiter in a 5.857-d orbit, while TOI-163b is an inflated (⁠|$R_ \rm{P}$| = |$1.478^{+0.022}_{-0.029} \,\mathrm{ R}_ \rm{J}$|⁠ , |$M_ \rm{P}$| = |$1.219\pm 0.11 \, \rm{M}_ \rm{J}$|⁠) hot Jupiter on a P = 4.231-d orbit; both planets orbit F-type stars. A particularly interesting result is that TOI-150b shows an eccentric orbit (⁠|$e=0.262^{+0.045}_{-0.037}$|⁠), which is quite uncommon among hot Jupiters. We estimate that this is consistent, however, with the circularization time-scale, which is slightly larger than the age of the system. These two hot Jupiters are both prime candidates for further characterization – in particular, both are excellent candidates for determining spin-orbit alignments via the Rossiter–McLaughlin (RM) effect and for characterizing atmospheric thermal structures using secondary eclipse observations considering they are both located closely to the James Webb Space Telescope (JWST) Continuous Viewing Zone (CVZ). [ABSTRACT FROM AUTHOR]

Massive companions in close orbits around G dwarfs are thought to undergo rapid orbital decay due to runaway tidal dissipation. We report here the discovery of WASP-128b, a brown dwarf discovered by the WASP survey transiting a G0V host on a |$2.2\, \mathrm{d}$| orbit, where the measured stellar rotation rate places the companion in a regime where tidal interaction is dominated by dynamical tides. Under the assumption of dynamical equilibrium, we derive a value of the stellar tidal quality factor |$\log {Q_\star ^{\prime }} = 6.96 \pm 0.19$|⁠. A combined analysis of ground-based photometry and high-resolution spectroscopy reveals a mass and radius of the host, |$M_\star = 1.16\pm 0.04\, \mathrm{M}_{\odot }$|⁠, |$R_\star = 1.16\pm 0.02\, \mathrm{R}_{\odot }$|⁠, and for the companion, |$M_\mathrm{b} = 37.5\pm 0.8\, M_\mathrm{J}$|⁠, |$R_\mathrm{b} = 0.94\pm 0.02\, R_\mathrm{J}$|⁠, placing WASP-128b in the driest parts of the brown dwarf desert, and suggesting a mild inflation for its age. We estimate a remaining lifetime for WASP-128b similar to that of some ultra-short period massive hot Jupiters, and note it may be a propitious candidate for measuring orbital decay and testing tidal theories. [ABSTRACT FROM AUTHOR]

We report the detection of two new systems containing transiting planets. Both were identified by WASP as worthy transiting planet candidates. Radial velocity observations quickly verified that the photometric signals were indeed produced by two transiting hot Jupiters. Our observations also show the presence of additional Doppler signals. In addition to short-period hot Jupiters, we find that the WASP-53 and WASP-81 systems also host brown dwarfs, on fairly eccentric orbits with semimajor axes of a few astronomical units. WASP-53c is over 16 MJupsin ic andWASP-81c is 57 MJupsin ic. The presence of these tight, massive companions restricts theories of how the inner planets were assembled. We propose two alternative interpretations: the formation of the hot Jupiters within the snow line or the late dynamical arrival of the brown dwarfs after disc dispersal.We also attempted to measure the Rossiter-McLaughlin effect for both hot Jupiters. In the case ofWASP-81b, we fail to detect a signal. ForWASP-53b, we find that the planet is aligned with respect to the stellar spin axis. In addition we explore the prospect of transit-timing variations, and of using Gaia's astrometry to measure the true masses of both brown dwarfs and also their relative inclination with respect to the inner transiting hot Jupiters. [ABSTRACT FROM AUTHOR]