TOI-222: A single-transit TESS candidate revealed to be a 34-d eclipsing binary with CORALIE, EulerCam, and NGTS

We report the period, eccentricity, and mass determination for the Transiting Exoplanet Survey Satellite (TESS) single-transit event candidate TOI-222, which displayed a single 3000 ppm transit in the TESS 2-min cadence data from Sector 2. We determine the orbital period via radial velocity measurements (P = 33.9 d), which allowed for ground-based photometric detection of two subsequent transits. Our data show that the companion to TOI-222 is a low-mass star, with a radius of 0.18+−003910 R☉ and a mass of 0.23 ± 0.01 M☉. This discovery showcases the ability to efficiently discover long-period systems from TESS single-transit events using a combination of radial velocity monitoring coupled with high-precision ground-based photometry

An ultrahot Neptune in the Neptune desert

About 1 out of 200 Sun-like stars has a planet with an orbital period shorter than one day: an ultrashort-period planet1,2. All of the previously known ultrashort-period planets are either hot Jupiters, with sizes above 10 Earth radii (R⊕), or apparently rocky planets smaller than 2 R⊕. Such lack of planets of intermediate size (the ‘hot Neptune desert’) has been interpreted as the inability of low-mass planets to retain any hydrogen/helium (H/He) envelope in the face of strong stellar irradiation. Here we report the discovery of an ultrashort-period planet with a radius of 4.6 R⊕ and a mass of 29 M⊕, firmly in the hot Neptune desert. Data from the Transiting Exoplanet Survey Satellite3 revealed transits of the bright Sun-like star LTT 9779 every 0.79 days. The planet’s mean density is similar to that of Neptune, and according to thermal evolution models, it has a H/He-rich envelope constituting 9.0−2.9+2.7% of the total mass. With an equilibrium temperature around 2,000 K, it is unclear how this ‘ultrahot Neptune’ managed to retain such an envelope. Follow-up observations of the planet’s atmosphere to better understand its origin and physical nature will be facilitated by the star’s brightness (Vmag = 9.8)

A study of plasma-related ion-surface interactions

The sputtering effects of plasma-related ion-surface interactions have been investigated by measuring the energy distributions of ions and neutrals sputtered by low energy (<3.6 keV) atomic and molecular ions. To study the neutral atoms a post-ionisation step is required. This is achieved by using a nonresonant multiphoton ionisation (NRMPI) at #lambda#=248nm. Ar"+, N_1"+, N_2"+ and CF_2"+ were used to bombard the surfaces of polycrystalline copper and single crystal <100> silicon. The energy distributions of both the sputtered ions and neutrals was performed by a combination quadrupole mass spectrometry and time-of-flight analysis. The energy distributions for secondary ions were obtained for both monatomic silicon and monatomic copper. The energy distributions for neutral copper atoms are also reported. The energy analysis of the sputtered secondary ions and atoms can be explained in the context of a linear collision cascade model. The high energy tall of the energy spectra can be fitted to an E"-"n power dependence with the value of n increasing as the primary ion energy drops. The ability of the system to measure both sputtered ions and neutrals enabled the ionisation probability, i.e. the variation of the ionisation fraction with exiting kinetic energy to be obtained. Results obtained for polycrystalline copper sputtered by 3.6 keV Ar"+, 1.8 keV N_1"+ and 1.8 and 3.6 keV CF_2"+ are presented. (author)SIGLEAvailable from British Library Document Supply Centre-DSC:DXN0267009 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

A BAC Transgene Expressing Human CFTR under Control of Its Regulatory Elements Rescues Cftr Knockout Mice

Small-molecule modulators of cystic fibrosis transmembrane conductance regulator (CFTR) biology show promise in the treatment of cystic fibrosis (CF). A Cftr knockout (Cftr KO) mouse expressing mutants of human CFTR would advance in vivo testing of new modulators. A bacterial artificial chromosome (BAC) carrying the complete hCFTR gene including regulatory elements within 40.1 kb of DNA 5′ and 25 kb of DNA 3′ to the gene was used to generate founder mice expressing hCFTR. Whole genome sequencing indicated a single integration site on mouse chromosome 8 (8qB2) with ~6 gene copies. hCFTR+ offspring were bred to murine Cftr KO mice, producing hCFTR+/mCftr− (H+/m−) mice, which had normal survival, growth and goblet cell function as compared to wild-type (WT) mice. Expression studies showed hCFTR protein and transcripts in tissues typically expressing mCftr. Functionally, nasal potential difference and large intestinal short-circuit (Isc) responses to cAMP stimulation were similar in magnitude to WT mice, whereas small intestinal cAMP ΔIsc responses were reduced. A BAC transgenic mouse with functional hCFTR under control of its regulatory elements has been developed to enable the generation of mouse models of hCFTR mutations by gene editing for in vivo testing of new CF therapies. © 2019, The Author(s)