1,461 research outputs found
A Six-Planet System Around the Star HD 34445
We present a new precision radial velocity dataset that reveals a
multi-planet system orbiting the G0V star HD 34445. Our 18-year span consists
of 333 precision radial velocity observations, 56 of which were previously
published, and 277 which are new data from Keck Observatory, Magellan at Las
Campanas Observatory, and the Automated Planet Finder at Lick Observatory.
These data indicate the presence of six planet candidates in Keplerian motion
about the host star with periods of 1057, 215, 118, 49, 677, and 5700 days, and
minimum masses of 0.63, 0.17, 0.1, 0.05, 0.12 and 0.38 Jupiter masses
respectively. The HD 34445 planetary system, with its high degree of
multiplicity, its long orbital periods, and its induced stellar radial velocity
half-amplitudes in the range is fundamentally unlike either our own solar system (in which only
Jupiter and Saturn induce significant reflex velocities for the Sun), or the
Kepler multiple-transiting systems (which tend to have much more compact
orbital configurations)Comment: 10 pages, 11 figure
Extensive carbon isotopic heterogeneity among methane seep microbiota
To assess and study the heterogeneity of δ^(13)C values for seep microorganisms of the Eel River Basin, we studied two principally different sample sets: sediments from push cores and artificial surfaces colonized over a 14 month in situ incubation. In a single sediment core, the δ^(13)C compositions of methane seep-associated microorganisms were measured and the relative activity of several metabolisms was determined using radiotracers. We observed a large range of archaeal δ^(13)C values (> 50‰) in this microbial community. The δ^(13)C of ANME-1 rods ranged from −24‰ to −87‰. The δ^(13)C of ANME-2 sarcina ranged from −18‰ to −75‰. Initial measurements of shell aggregates were as heavy as −19.5‰ with none observed to be lighter than −57‰. Subsequent measurements on shell aggregates trended lighter reaching values as ^(13)C-depleted as −73‰. The observed isotopic trends found for mixed aggregates were similar to those found for shell aggregates in that the initial measurements were often enriched and the subsequent analyses were more ^(13)C-depleted (with values as light as −56‰). The isotopic heterogeneity and trends observed within taxonomic groups suggest that ANME-1 and ANME-2 sarcina are capable of both methanogenesis and methanotrophy. In situ microbial growth was investigated by incubating a series of slides and silicon (Si) wafers for 14 months in seep sediment. The experiment showed ubiquitous growth of bacterial filaments (mean δ^(13)C = −38 ± 3‰), suggesting that this bacterial morphotype was capable of rapid colonization and growth
Patients hospitalized with acute heart failure, worsening renal function, and persistent congestion are at high risk for adverse outcomes despite current medical therapy
INTRODUCTION: Approximately 1/3 of patients with acute decompensated heart failure (ADHF) are discharged with persistent congestion. Worsening renal function (WRF) occurs in approximately 50% of patients hospitalized for ADHF and the combination of WRF and persistent congestion are associated with higher risk of mortality and HF readmissions.
METHODS: We designed a multicenter, prospective registry to describe current treatments and outcomes for patients hospitalized with ADHF complicated by WRF (defined as a creatinine increase ≥0.3 mg/dL) and persistent congestion at 96 h. Study participants were followed during the hospitalization and through 90-day post-discharge. Hospitalization costs were analyzed in an economic substudy.
RESULTS: We enrolled 237 patients hospitalized with ADHF, who also had WRF and persistent congestion. Among these, the average age was 66 ± 13 years and 61% had a left ventricular ejection fraction (LVEF) ≤ 40%. Mean baseline creatinine was 1.7 ± 0.7 mg/dL. Patients with persistent congestion had a high burden of clinical events during the index hospitalization (7.6% intensive care unit transfer, 2.1% intubation, 1.7% left ventricular assist device implantation, and 0.8% dialysis). At 90-day follow-up, 33% of patients were readmitted for ADHF or died. Outcomes and costs were similar between patients with reduced and preserved LVEF.
CONCLUSIONS: Many patients admitted with ADHF have WRF and persistent congestion despite diuresis and are at high risk for adverse events during hospitalization and early follow-up. Novel treatment strategies are urgently needed for this high-risk population
A TESS Dress Rehearsal: Planetary Candidates and Variables from K2 Campaign 17T
We produce light curves for all ∼34,000 targets observed with K2 in Campaign 17 (C17), identifying 34 planet candidates, 184 eclipsing binaries, and other 222 periodic variables. The forward-facing direction of the C17 field means follow-up can begin immediately now that the campaign has concluded and interesting targets have been identified. The C17 field has a large overlap with C6, so this latest campaign also offers an infrequent opportunity to study a large number of targets already observed in a previous K2 campaign. The timing of the C17 data release, shortly before science operations begin with the Transiting Exoplanet Survey Satellite (TESS), also lets us exercise some of the tools and methods developed for identification and dissemination of planet candidates from TESS. We find excellent agreement between these results and those identified using only K2-based tools. Among our planet candidates are several planet candidates with sizes <4 R[subscript ⊕] and orbiting stars with Kp ≲ 10 (indicating good RV targets of the sort TESS hopes to find) and a Jupiter-sized single-transit event around a star already hosting a 6 day planet candidate. Key words: methods, data analysis, planets and satellites, detection – techniques, photometricUnited States. National Aeronautics and Space Administration (K2GO Grant 80NSSC18K0308
TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844
Data from the newly-commissioned \textit{Transiting Exoplanet Survey
Satellite} (TESS) has revealed a "hot Earth" around LHS 3844, an M dwarf
located 15 pc away. The planet has a radius of and
orbits the star every 11 hours. Although the existence of an atmosphere around
such a strongly irradiated planet is questionable, the star is bright enough
(, ) for this possibility to be investigated with transit and
occultation spectroscopy. The star's brightness and the planet's short period
will also facilitate the measurement of the planet's mass through Doppler
spectroscopy.Comment: 10 pages, 4 figures. Submitted to ApJ Letters. This letter makes use
of the TESS Alert data, which is currently in a beta test phase, using data
from the pipelines at the TESS Science Office and at the TESS Science
Processing Operations Cente
TOI-1685 b Is a Hot Rocky Super-Earth: Updates to the Stellar and Planet Parameters of a Popular JWST Cycle 2 Target
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
TESS Discovery of a Transiting Super-Earth in the Mensae System
We report the detection of a transiting planet around Mensae (HD
39091), using data from the Transiting Exoplanet Survey Satellite (TESS). The
solar-type host star is unusually bright (V=5.7) and was already known to host
a Jovian planet on a highly eccentric, 5.7-year orbit. The newly discovered
planet has a size of and an orbital period of 6.27
days. Radial-velocity data from the HARPS and AAT/UCLES archives also displays
a 6.27-day periodicity, confirming the existence of the planet and leading to a
mass determination of . The star's proximity and
brightness will facilitate further investigations, such as atmospheric
spectroscopy, asteroseismology, the Rossiter--McLaughlin effect, astrometry,
and direct imaging.Comment: Accepted for publication ApJ Letters. This letter makes use of the
TESS Alert data, which is currently in a beta test phase. The discovery light
curve is included in a table inside the arxiv submissio
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