75 research outputs found

    A ground-based NUV secondary eclipse observation of KELT-9b

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    KELT-9b is a recently discovered exoplanet with a 1.49 d orbit around a B9.5/A0-type star. The unparalleled levels of UV irradiation it receives from its host star put KELT-9b in its own unique class of ultra-hot Jupiters, with an equilibrium temperature > 4000 K. The high quantities of dissociated hydrogen and atomic metals present in the dayside atmosphere of KELT-9b bear more resemblance to a K-type star than a gas giant. We present a single observation of KELT-9b during its secondary eclipse, taken with the Wide Field Camera on the Isaac Newton Telescope (INT). This observation was taken in the U-band, a window particularly sensitive to Rayleigh scattering. We do not detect a secondary eclipse signal, but our 3σ\sigma upper limit of 181 ppm on the depth allows us to constrain the dayside temperature of KELT-9b at pressures of ~30 mbar to 4995 K (3σ\sigma). Although we can place an observational constraint of Ag<A_g< 0.14, our models suggest that the actual value is considerably lower than this due to H^- opacity. This places KELT-9b squarely in the albedo regime populated by its cooler cousins, almost all of which reflect very small components of the light incident on their daysides. This work demonstrates the ability of ground-based 2m-class telescopes like the INT to perform secondary eclipse studies in the NUV, which have previously only been conducted from space-based facilities.Comment: Accepted in ApJL. 7 pages, 3 figure

    The influence of caffeine expectancies on sport, exercise and cognitive performance

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    Caffeine (CAF) is widely consumed across sport and exercise for its reputed ergogenic properties, including central nervous stimulation and enhanced muscular force development. However, expectancy and the related psychological permutations that are associated with oral CAF ingestion are generally not considered in most experimental designs and these could be important in understanding if/how CAF elicits an ergogenic effect. The present paper reviews 17 intervention studies across sport, exercise, and cognitive performance. All explore CAF expectancies, in conjunction with/without CAF pharmacology. Thirteen out of 17 studies indicated expectancy effects of varying magnitudes across a range of exercise tasks and cognitive skills inclusive off but not limited to; endurance capacity, weightlifting performance, simple reaction time and memory. Factors, such as motivation, belief, and habitual CAF consumption habits influenced the response. In many instances, these effects were comparable to CAF pharmacology. Given these findings and the lack of consistency in the experimental design, future research acknowledging factors, such as habitual CAF consumption habits, habituated expectations, and the importance of subjective post-hoc analysis will help to advance knowledge within this area.N/

    Spectroscopic Transit Search: a self-calibrating method for detecting planets around bright stars

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    We search for transiting exoplanets around the star β\beta Pictoris using high resolution spectroscopy and Doppler imaging that removes the need for standard star observations. These data were obtained on the VLT with UVES during the course of an observing campaign throughout 2017 that monitored the Hill sphere transit of the exoplanet β\beta Pictoris b. We utilize line profile tomography as a method for the discovery of transiting exoplanets. By measuring the exoplanet distortion of the stellar line profile, we remove the need for reference star measurements. We demonstrate the method with white noise simulations, and then look at the case of β\beta Pictoris, which is a δ\delta Scuti pulsator. We describe a method to remove the stellar pulsations and perform a search for any transiting exoplanets in the resultant data set. We inject fake planet transits with varying orbital periods and planet radii into the spectra and determine the recovery fraction. In the photon noise limited case we can recover planets down to a Neptune radius with an \sim80% success rate, using an 8 m telescope with a R100,000R\sim 100,000 spectrograph and 20 minutes of observations per night. The pulsations of β\beta Pictoris limit our sensitivity to Jupiter-sized planets, but a pulsation removal algorithm improves this limit to Saturn-sized planets. We present two planet candidates, but argue that their signals are most likely caused by other phenomena. We have demonstrated a method for searching for transiting exoplanets that (i) does not require ancillary calibration observations, (ii) can work on any star whose rotational broadening can be resolved with a high spectral dispersion spectrograph and (iii) provides the lowest limits so far on the radii of transiting Jupiter-sized exoplanets around β\beta Pictoris with orbital periods from 15 days to 200 days with >50% coverage.Comment: Accepted for publication in A&A, 8 pages, 8 figures. The Github repository can be found at https://github.com/lennartvansluijs/Spectroscopic-Transit-Searc

    Extreme asteroids in the Pan-STARRS 1 Survey

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    Using the first 18 months of the Pan-STARRS 1 survey we have identified 33 candidate high-amplitude objects for follow-up observations and carried out observations of 22 asteroids. 4 of the observed objects were found to have observed amplitude Aobs1.0A_{obs}\geq 1.0 mag. We find that these high amplitude objects are most simply explained by single rubble pile objects with some density-dependent internal strength, allowing them to resist mass shedding even at their highly elongated shapes. 3 further objects although below the cut-off for 'high-amplitude' had a combination of elongation and rotation period which also may require internal cohesive strength, depending on the density of the body. We find that none of the 'high-amplitude asteroids' identified here require any unusual cohesive strengths to resist rotational fission. 3 asteroids were sufficiently observed to allow for shape and spin pole models to be determined through light curve inversion. 45864 was determined to have retrograde rotation with spin pole axes λ=218±10,β=82±5\lambda=218\pm 10^{\circ}, \beta=-82\pm 5^{\circ} and asteroid 206167 was found to have best fit spin pole axes λ=57±5\lambda= 57 \pm 5^{\circ}, β=67±5\beta=-67 \pm 5^{\circ}. An additional object not initially measured with Aobs>1.0A_{obs}>1.0 mag, 49257, was determined to have a shape model which does suggest a high-amplitude object. Its spin pole axes were best fit for values λ=112±6,β=6±5\lambda=112\pm 6^{\circ}, \beta=6\pm 5^{\circ}. In the course of this project to date no large super-fast rotators (Prot<2.2P_{rot} < 2.2 h) have been identified.Comment: 31 pages; accepted by A

    The Influence of Caffeine Expectancies on Simulated Soccer Performance in Recreational Individuals

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    Caffeine (CAF) has been reported to improve various facets associated with successful soccer play, including gross motor skill performance, endurance capacity and cognition. These benefits are primarily attributed to pharmacological mechanisms. However, evidence assessing CAF’s overall effects on soccer performance are sparse with no studies accounting for CAF’s potential psychological impact. Therefore, the aim of this study was to assess CAF’s psychological vs. pharmacological influence on various facets of simulated soccer performance. Utilising a double-dissociation design, eight male recreational soccer players (age: 22 ± 5 years, body mass: 78 ± 16 kg, height: 178 ± 6 cm) consumed CAF (3 mg/kg/body mass) or placebo (PLA) capsules, 60 min prior to performing the Loughborough Intermittent Shuttle Test (LIST) interspersed with a collection of ratings of perceived exertion (RPE), blood glucose and lactate, heart rate and performing the Loughborough Soccer Passing Test (LSPT). Whole-body dynamic reaction time (DRT) was assessed pre- and post- LIST, and endurance capacity (TLIM) post, time-matched LIST. Statistical analysis was performed using IBM SPSS (v24) whilst subjective perceptions were explored using template analysis. Mean TLIM was greatest (p < 0.001) for synergism (given CAF/told CAF) (672 ± 132 s) vs. placebo (given PLA/told PLA) (533 ± 79 s). However, when isolated, TLIM was greater (p = 0.012) for CAF psychology (given PLA/told CAF) (623 ± 117 s) vs. pharmacology (given CAF/told PLA) (578 ± 99 s), potentially, via reduced RPE. Although DRT performance was greater (p = 0.024) post-ingestion (+5 hits) and post-exercise (+7 hits) for pharmacology vs. placebo, psychology and synergism appeared to improve LSPT performance vs. pharmacology. Interestingly, positive perceptions during psychology inhibited LSPT and DRT performance via potential CAF over-reliance, with the opposite occurring following negative perceptions. The benefits associated with CAF expectancies may better suit tasks that entail lesser cognitive-/skill-specific attributes but greater gross motor function and this is likely due to reduced RPE. In isolation, these effects appear greater vs. CAF pharmacology. However, an additive benefit may be observed after combining expectancy with CAF pharmacology (i.e., synergism).N/

    TOI-1685 b Is a Hot Rocky Super-Earth: Updates to the Stellar and Planet Parameters of a Popular JWST Cycle 2 Target

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    We present an updated characterization of the TOI-1685 planetary system, which consists of a P b = 0.69 day ultra-short-period super-Earth planet orbiting a nearby (d = 37.6 pc) M2.5V star (TIC 28900646, 2MASS J04342248+4302148). This planet was previously featured in two contemporaneous discovery papers, but the best-fit planet mass, radius, and bulk density values were discrepant, allowing it to be interpreted either as a hot, bare rock or a 50% H2O/50% MgSiO3 water world. TOI-1685 b will be observed in three independent JWST Cycle 2 programs, two of which assume the planet is a water world, while the third assumes that it is a hot rocky planet. Here we include a refined stellar classification with a focus on addressing the host star’s metallicity, an updated planet radius measurement that includes two sectors of TESS data and multicolor photometry from a variety of ground-based facilities, and a more accurate dynamical mass measurement from a combined CARMENES, InfraRed Doppler, and MAROON-X radial velocity data set. We find that the star is very metal-rich ([Fe/H] ≃ +0.3) and that the planet is systematically smaller, lower mass, and higher density than initially reported, with new best-fit parameters of R pl = 1.468 −0.051+0.050 R ⊕ and M pl = 3.03−0.32+0.33 M ⊕. These results fall in between the previously derived values and suggest that TOI-1685 b is a hot rocky planet with an Earth-like density (ρ pl = 5.3 ± 0.8 g cm−3, or 0.96 ρ ⊕), high equilibrium temperature (T eq = 1062 ± 27 K), and negligible volatiles, rather than a water world

    Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TESS and CHEOPS

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    We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors 42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory, as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of 12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy

    Gliese 12 b, a temperate Earth-sized planet at 12 parsecs discovered with TESS and CHEOPS

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    We report on the discovery of Gliese 12 b, the nearest transiting temperate, Earth-sized planet found to date. Gliese 12 is a bright (V = 12.6 mag, K = 7.8 mag) metal-poor M4V star only 12.162 ± 0.005 pc away from the Solar system with one of the lowest stellar activity levels known for M-dwarfs. A planet candidate was detected by TESS based on only 3 transits in sectors 42, 43, and 57, with an ambiguity in the orbital period due to observational gaps. We performed follow-up transit observations with CHEOPS and ground-based photometry with MINERVA-Australis, SPECULOOS, and Purple Mountain Observatory, as well as further TESS observations in sector 70. We statistically validate Gliese 12 b as a planet with an orbital period of 12.76144 ± 0.00006 d and a radius of 1.0 ± 0.1 R⊕, resulting in an equilibrium temperature of ∼315 K. Gliese 12 b has excellent future prospects for precise mass measurement, which may inform how planetary internal structure is affected by the stellar compositional environment. Gliese 12 b also represents one of the best targets to study whether Earth-like planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on Earth and across the galaxy

    NGTS-28Ab: A short period transiting brown dwarf

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    We report the discovery of a brown dwarf orbiting a M1 host star. We first identified the brown dwarf within the Next Generation Transit Survey data, with supporting observations found in TESS sectors 11 and 38. We confirmed the discovery with follow-up photometry from the South African Astronomical Observatory, SPECULOOS-S, and TRAPPIST-S, and radial velocity measurements from HARPS, which allowed us to characterise the system. We find an orbital period of ~1.25 d, a mass of 69.0+5.3-4.8 MJ, close to the Hydrogen burning limit, and a radius of 0.95 +- 0.05 RJ. We determine the age to be >0.5 Gyr, using model isochrones, which is found to be in agreement with SED fitting within errors. NGTS-28Ab is one of the shortest period systems found within the brown dwarf desert, as well as one of the highest mass brown dwarfs that transits an M dwarf. This makes NGTS-28Ab another important discovery within this scarcely populated region.Comment: 20 pages (inc. appendices), 16 figures, accepted for publication in MNRA

    A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS

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    We report on the confirmation and follow-up characterization of two long-period transiting substellar companions on low-eccentricity orbits around TIC 4672985 and TOI-2529, whose transit events were detected by the TESS space mission. Ground-based photometric and spectroscopic follow up from different facilities, confirmed the substellar nature of TIC 4672985 b, a massive gas giant, in the transition between the super-Jupiters and brown-dwarfs mass regime. From the joint analysis we derived the following orbital parameters: P = 69.0480+0.0004−0.0005 d, Mp = 12.74+1.01−1.01 MJ, Rp =1.026+0.065−0.067 RJ and e = 0.018+0.004−0.004 . In addition, the RV time series revealed a significant trend at the ∼ 350 m s−1 yr−1level, which is indicative of the presence of a massive outer companion in the system. TIC 4672985 b is a unique example of a transiting substellar companion with a mass above the deuterium-burning limit, located beyond 0.1 AU and in a nearly circular orbit. These planetary properties are difficult to reproduce from canonical planet formation and evolution models. For TOI-2529 b, we obtained the following orbital parameters: P = 64.5949+0.0003−0.0003 d, Mp =2.340+0.197−0.195 MJ, Rp = 1.030+0.050−0.050 RJ and e = 0.021+0.024−0.015 , making this object a new example of a growing population of transiting warm giant planets
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