We report the discovery of a new ultra-short-period planet and summarize the properties of all such planets for which the mass and radius have been measured. The new planet, K2-131b, was discovered ...in K2 Campaign 10. It has a radius of and orbits a G dwarf with a period of 8.9 hr. Radial velocities obtained with Magellan/PFS and TNG/HARPS-N show evidence for stellar activity along with orbital motion. We determined the planetary mass using two different methods: (1) the "floating chunk offset" method, based only on changes in velocity observed on the same night; and (2) a Gaussian process regression based on both the radial velocity and photometric time series. The results are consistent and lead to a mass measurement of and a mean density of g cm−3.
The systemic inflammatory response syndrome (SIRS) frequently occurs in patients with cardiogenic shock and may aggravate shock severity and organ failure. We sought to determine the association of ...SIRS with illness severity and survival across the spectrum of shock severity in cardiac intensive care unit (CICU) patients.
We retrospectively analyzed 8995 unique patients admitted to the Mayo Clinic CICU between 2007 and 2015. Patients with ≥2/4 SIRS criteria based on admission laboratory and vital sign data were considered to have SIRS. Patients were stratified by the 2019 Society for Cardiovascular Angiography and Interventions (SCAI) shock stages using admission data. The association between SIRS and mortality was evaluated across SCAI shock stage using logistic regression and Cox proportional-hazards models for hospital and 1-year mortality, respectively.
The study population had a mean age of 67.5±15.2 years, including 37.2% women. SIRS was present in 33.9% of patients upon CICU admission and was more prevalent in advanced SCAI shock stages. Patients with SIRS had higher illness severity, worse shock, and more organ failure, with an increased risk of mortality during hospitalization (16.8% versus 3.8%; adjusted odds ratio, 2.1 95% CI, 1.7-2.5;
<0.001) and at 1 year (adjusted hazard ratio, 1.4 95% CI, 1.3-1.6;
<0.001). After multivariable adjustment, SIRS was associated with higher hospital and 1-year mortality among patients in SCAI shock stages A through D (all
<0.01) but not SCAI shock stage E.
One-third of CICU patients meet clinical criteria for SIRS at the time of admission, and these patients have higher illness severity and worse outcomes across the spectrum of SCAI shock stages. The presence of SIRS identified CICU patients at increased risk of short-term and long-term mortality. Further study is needed to determine whether systemic inflammation truly drives SIRS in this population and whether patients with SIRS respond differently to supportive therapies for shock.
We present the first comprehensive look at the 0.35-5 m transmission spectrum of the warm (∼800 K) Neptune HAT-P-11b derived from 13 individual transits observed using the Hubble and Spitzer Space ...Telescopes. Along with the previously published molecular absorption feature in the 1.1-1.7 m bandpass, we detect a distinct absorption feature at 1.15 m and a weak feature at 0.95 m, indicating the presence of water and/or methane with a combined significance of 4.4 . We find that this planet's nearly flat optical transmission spectrum and attenuated near-infrared molecular absorption features are best matched by models incorporating a high-altitude cloud layer. Atmospheric retrievals using the combined 0.35-1.7 m Hubble Space Telescope (HST) transmission spectrum yield strong constraints on atmospheric cloud-top pressure and metallicity, but we are unable to match the relatively shallow Spitzer transit depths without underpredicting the strength of the near-infrared molecular absorption bands. HAT-P-11b's HST transmission spectrum is well matched by predictions from our microphysical cloud models. Both forward models and retrievals indicate that HAT-P-11b most likely has a relatively low atmospheric metallicity (<4.6 Z and <86 Z at the 2 and 3 levels respectively), in contrast to the expected trend based on the solar system planets. Our work also demonstrates that the wide wavelength coverage provided by the addition of the HST STIS data is critical for making these inferences.
Based on two decades of radial velocity (RV) observations using Keck/High Resolution Echelle Spectrometer (HIRES) and McDonald/Tull, and more recent observations using the Automated Planet Finder, we ...found that the nearby star HR 5183 (HD 120066) hosts a 3 minimum mass planet with an orbital period of yr. The orbit is highly eccentric (e 0.84), shuttling the planet from within the orbit of Jupiter to beyond the orbit of Neptune. Our careful survey design enabled high cadence observations before, during, and after the planet's periastron passage, yielding precise orbital parameter constraints. We searched for stellar or planetary companions that could have excited the planet's eccentricity, but found no candidates, potentially implying that the perturber was ejected from the system. We did identify a bound stellar companion more than 15,000 au from the primary, but reasoned that it is currently too widely separated to have an appreciable effect on HR 5183 b. Because HR 5183 b's wide orbit takes it more than 30 au (1″) from its star, we also explored the potential of complimentary studies with direct imaging or stellar astrometry. We found that a Gaia detection is very likely, and that imaging at 10 m is a promising avenue. This discovery highlights the value of long-baseline RV surveys for discovering and characterizing long-period, eccentric Jovian planets. This population may offer important insights into the dynamical evolution of planetary systems containing multiple massive planets.
We present 11 years of HIRES precision radial velocities (RVs) of the nearby M3V star Gliese 581, combining our data set of 122 precision RVs with an existing published 4.3-year set of 119 HARPS ...precision RVs. The velocity set now indicates six companions in Keplerian motion around this star. Differential photometry indicates a likely stellar rotation period of ~94 days and reveals no significant periodic variability at any of the Keplerian periods, supporting planetary orbital motion as the cause of all the RV variations. The combined data set strongly confirms the 5.37-day, 12.9-day, 3.15-day, and 67-day planets previously announced by Bonfils et al., Udry et al., and Mayor et al.. The observations also indicate a fifth planet in the system, GJ 581f, a minimum-mass 7.0 M {circled plus} planet orbiting in a 0.758 AU orbit of period 433 days, and a sixth planet, GJ 581g, a minimum-mass 3.1 M {circled plus} planet orbiting at 0.146 AU with a period of 36.6 days. The estimated equilibrium temperature of GJ 581g is 228 K, placing it squarely in the middle of the habitable zone of the star and offering a very compelling case for a potentially habitable planet around a very nearby star. That a system harboring a potentially habitable planet has been found this nearby, and this soon in the relatively early history of precision RV surveys, indicates that Delta *h{circled plus}, the fraction of stars with potentially habitable planets, is likely to be substantial. This detection, coupled with statistics of the incompleteness of present-day precision RV surveys for volume-limited samples of stars in the immediate solar neighborhood, suggests that Delta *h{circled plus} could well be on the order of a few tens of percent. If the local stellar neighborhood is a representative sample of the galaxy as a whole, our Milky Way could be teeming with potentially habitable planets.
Acidosis and higher lactate predict worse outcomes in cardiogenic shock (CS) patients. We sought to determine whether overall acidosis severity on admission predicted in-hospital mortality in CS ...patients.
This retrospective descriptive analysis included CS patients admitted to a single academic tertiary cardiac intensive care unit from 2007 to 2015. Admission arterial pH, base excess, and anion gap values were used to generate a Composite Acidosis Score (range 0-5, with a score ≥2 defining Severe Acidosis). Adjusted in-hospital mortality was analyzed using multivariable logistic regression.
We included 1,065 patients with median age of 68.9 (59.0, 77.2) years (36.4% females). Concomitant diagnoses included cardiac arrest in 38.1% and acute coronary syndrome in 59.1%. Severe Acidosis was present in 35.2%, and these patients had worse shock and more organ failure. In-hospital mortality occurred in 34.1% and was higher among patients with Severe Acidosis (54.9% vs. 22.4%, adjusted odds ratio OR 2.01, 95% CI 1.43-2.83, P < 0.001). Increasing Composite Acidosis Score was associated with higher in-hospital mortality (adjusted OR 1.25 per point, 95% CI 1.11-1.40, P < 0.001). Severe Acidosis was associated with higher hospital mortality at every level of shock severity and organ failure (all P < 0.05). Admission lactate level had equivalent discrimination for in-hospital mortality as the Composite Acidosis Score (0.69 vs. 0.66; P = 0.32 by De Long test).
Given its incremental association with higher in-hospital mortality among CS patients beyond shock severity and organ failure, we propose Severe Acidosis as a marker of hemometabolic shock. Lactate levels performed as well as a composite measure of acidosis for predicting mortality.
From numerous radial velocities as well as Johnson B and V differential photoelectric photometry, we have determined the orbital elements and other properties of the single-lined triple system HD ...126516. This system consists of a narrow-lined F5 V star and an unseen M dwarf companion in a 2.1241 day circular orbit. The small, low-mass secondary produces detectable eclipses of the primary, and that pair has been given the variable star name V349 Vir. Variations of the center-of-mass velocity of this short-period system have an orbital period of 702.7 days or 1.92 yr and an eccentricity of 0.36. The third star is likely a K or M dwarf. From an analysis of our photometry, we conclude that the primary of HD 126516 is not a γ Dor variable. Comparison with evolutionary tracks indicates that the primary is slightly metal-poor and has an age of 2.5 Gyr. The projected rotational velocity of the primary is very low, just 4 km s−1, which is 10 times less than its synchronous rotational velocity. Thus, either that component's rotation is extremely non-synchronous or the inclinations of the rotational and orbital axes are very different, and so the primary has a very large spin-orbit misalignment. Because of the moderate age of the system and the fact that its orbit is already circularized, neither situation is expected theoretically.
In this paper, we describe a uniform analysis of eight transits and eleven secondary eclipses of the extrasolar planet GJ 436b obtained in the 3.6, 4.5, and 8.0 Delta *mm bands using the IRAC ...instrument on the Spitzer Space Telescope between UT 2007 June 29 and UT 2009 February 4. We find that the best-fit transit depths for visits in the same bandpass can vary by as much as 8% of the total (4.7 Delta *s significance) from one epoch to the next. Although we cannot entirely rule out residual detector effects or a time-varying, high-altitude cloud layer in the planet's atmosphere as the cause of these variations, we consider the occultation of active regions on the star in a subset of the transit observations to be the most likely explanation. We find that for the deepest 3.6 Delta *mm transit the in-transit data have a higher standard deviation than the out-of-transit data, as would be expected if the planet occulted a star spot. We also compare all published transit observations for this object and find that transits observed in the infrared typically have smaller timing offsets than those observed in visible light. In this case, the three deepest Spitzer transits are all measured within a period of five days, consistent with a single epoch of increased stellar activity. We reconcile the presence of magnetically active regions with the lack of significant visible or infrared flux variations from the star by proposing that the star's spin axis is tilted with respect to our line of sight and that the planet's orbit is therefore likely to be misaligned. In contrast to the results reported by Beaulieu et al., we find no convincing evidence for methane absorption in the planet's transmission spectrum. If we exclude the transits that we believe to be most affected by stellar activity, we find that we prefer models with enhanced CO and reduced methane, consistent with GJ 436b's dayside composition from Stevenson et al. It is also possible that all transits are significantly affected by this activity, in which case it may not be feasible to characterize the planet's transmission spectrum using broadband photometry obtained over multiple epochs. These observations serve to illustrate the challenges associated with transmission spectroscopy of planets orbiting late-type stars; we expect that other systems, such as GJ 1214, may display comparably variable transit depths. We compare the limb-darkening coefficients predicted by PHOENIX and ATLAS stellar atmosphere models and discuss the effect that these coefficients have on the measured planet-star radius ratios given GJ 436b's near-grazing transit geometry. Our measured 8 Delta *mm secondary eclipse depths are consistent with a constant value, and we place a 1 Delta *s upper limit of 17% on changes in the planet's dayside flux in this band. These results are consistent with predictions from general circulation models for this planet, which find that the planet's dayside flux varies by a few percent or less in the 8 Delta *mm band. Averaging over the eleven visits gives us an improved estimate of 0.0452% ? 0.0027% for the secondary eclipse depth; we also examine residuals from the eclipse ingress and egress and place an upper limit on deviations caused by a non-uniform surface brightness for GJ 436b. We combine timing information from our observations with previously published data to produce a refined orbital ephemeris and determine that the best-fit transit and eclipse times are consistent with a constant orbital period. We find that the secondary eclipse occurs at a phase of 0.58672 ? 0.00017, corresponding to ecos ( Delta *w) = 0.13754 ? 0.00027, where e is the planet's orbital eccentricity and Delta *w is the longitude of pericenter. We also present improved estimates for other system parameters, including the orbital inclination, a/R , and the planet-star radius ratio.
We present an analysis of approx5 years of Lick Observatory radial velocity measurements targeting a uniform sample of 31 intermediate-mass (IM) subgiants (1.5 approx< M{sub *}/M{sub sun}approx< 2.0) ...with the goal of measuring the occurrence rate of Jovian planets around (evolved) A-type stars and comparing the distributions of their orbital and physical characteristics to those of planets around Sun-like stars. We provide updated orbital solutions incorporating new radial velocity measurements for five known planet-hosting stars in our sample; uncertainties in the fitted parameters are assessed using a Markov-Chain Monte Carlo method. The frequency of Jovian planets interior to 3 AU is 26{sup +9}{sub -8}%, which is significantly higher than the 5%-10% frequency observed around solar-mass stars. The median detection threshold for our sample includes minimum masses down to left brace0.2, 0.3, 0.5, 0.6, 1.3right brace M{sub Jup} within left brace0.1, 0.3, 0.6, 1.0, 3.0right brace AU. To compare the properties of planets around IM stars to those around solar-mass stars we synthesize a population of planets based on the parametric relationship dN propor to M {sup a}lpha P {sup b}eta dlnMdlnP, the observed planet frequency, and the detection limits we derived. We find that the values of alpha and beta for planets around solar-type stars from Cumming et al. fail to reproduce the observed properties of planets in our sample at the 4sigma level, even when accounting for the different planet occurrence rates. Thus, the properties of planets around A stars are markedly different than those around Sun-like stars, suggesting that only a small (approx50%) increase in stellar mass has a large influence on the formation and orbital evolution of planets.
Abstract
We have obtained high-dispersion spectroscopy and
BV
photometry of two F-type eclipsing binaries, HD 71636 and V1022 Cas, plus the A-type system OT And. Transiting Exoplanet Survey Satellite ...measurements for each system have also been incorporated. The photometry of HD 71636 enables a more consistent picture of this 5.01331 days, circular-orbit system to emerge. The F2 V primary has a mass of 1.506 ± 0.002
M
☉
and a radius of 1.583 ± 0.024
R
☉
. The mass of the F5 V secondary is 1.282 ± 0.002
M
☉
, and its radius is 1.314 ± 0.030
R
☉
. Comparison with evolutionary models of the Modules for Experiments in Stellar Astrophysics (MESA) series results in a good fit for a composition of Fe/H = 0.12 and an age of 0.9 Gyr. For the F6 V stars of V1022 Cas, our analysis produces a period of 12.15616 days and an eccentricity of 0.312. The two components have nearly equal masses of 1.626 ± 0.001
M
☉
and 1.607 ± 0.001
M
☉
. The radii of the primary and secondary are 2.570 ± 0.021
R
☉
and 2.445 ± 0.022
R
☉
, respectively. Comparison with the MESA evolutionary models results in Fe/H = 0.08 and an age of 1.87 Gyr. OT And consists of a pair of similar mid-A stars that have an orbital period of 20.85292 days and an eccentricity of 0.215. The primary has a mass of 2.253 ± 0.014
M
☉
and a radius of 3.167 ± 0.013
R
☉
. The corresponding parameters for the secondary are 2.147 ± 0.011
M
☉
and 2.649 ± 0.015
R
☉
, respectively. The MESA series models produce a best fit for this system with Fe/H = 0.10 and an age of 0.675 Gyr. The total apsidal motion in both eccentric systems is less than 1.°5 century
−1
.
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