Studies have shown that the remnants of destroyed planets and debris-disk planetesimals can survive the volatile evolution of their host stars into white dwarfs, but few intact planetary bodies ...around white dwarfs have been detected. Simulations predict that planets in Jupiter-like orbits around stars of ≲8 Mꙩ (solar mass) avoid being destroyed by the strong tidal forces of their stellar host, but as yet, there has been no observational confirmation of such a survivor. Here we report the non-detection of a main-sequence lens star in the microlensing event MOA-2010-BLG-477Lb using near-infrared observations from the Keck Observatory. We determine that this system contains a 0.53 ± 0.11 Mꙩ white-dwarf host orbited by a 1.4 ± 0.3 Jupiter-mass planet with a separation on the plane of the sky of 2.8 ± 0.5 astronomical units, which implies a semi-major axis larger than this. This system is evidence that planets around white dwarfs can survive the giant and asymptotic giant phases of their host’s evolution, and supports the prediction that more than half of white dwarfs have Jovian planetary companions. Located at approximately 2.0 kiloparsecs towards the center of our Galaxy, it is likely to represent an analogue to the end stages of the Sun and Jupiter in our own Solar System.
We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is ...injected by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23±3 km/s. The rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant κ^{2}∝r^{-2.8±0.8} rad^{2}/s^{2}. The plasma completes 0.5-2 full rotations in the experimental time frame (∼150 ns).
To obtain accurate mass measurements for cold planets discovered by microlensing, it is usually necessary to combine light curve modeling with at least two lens mass-distance relations. The physical ...parameters of the planetary system OGLE-2014-BLG-0124L have been constrained thanks to accurate parallax effect between ground-based and simultaneous space-based Spitzer observations. Here, we resolved the source+lens star from sub-arcsecond blends in H-band using adaptive optics (AO) observations with NIRC2 mounted on Keck II telescope. We identify additional flux, coincident with the source to within 160 mas. We estimate the potential contributions to this blended light (chance-aligned star, additional companion to the lens or to the source) and find that 85% of the NIR flux is due to the lens star at HL = 16.63 0.06 and KL = 16.44 0.06. We combined the parallax constraint and the AO constraint to derive the physical parameters of the system. The lensing system is composed of a mid-late type G main sequence star of ML = 0.9 0.05 M located at DL = 3.5 0.2 kpc in the Galactic disk. Taking the mass ratio and projected separation from the original study leads to a planet of Mp = 0.65 0.044 MJupiter at 3.48 0.22 au. Excellent parallax measurements from simultaneous ground-space observations have been obtained on the microlensing event OGLE-2014-BLG-0124, but it is only when they are combined with ∼30 minutes of Keck II AO observations that the physical parameters of the host star are well measured.
Abstract
The microlensing event OGLE-2017-BLG-1434 features a cold super-Earth planet that is 1 of 11 microlensing planets with a planet–host-star mass ratio of
q
< 1 × 10
−4
. We provide an ...additional mass–distance constraint on the lens host using near-infrared adaptive optics photometry from Keck/NIRC2. We are able to determine a flux excess of
K
L
= 16.96 ± 0.11, which most likely comes entirely from the lens star. Combining this with constraints from the large Einstein ring radius,
θ
E
= 1.40 ± 0.09 mas, and OGLE parallax we confirm this event as a super-Earth with a mass of
m
p
= 4.43 ± 0.25
M
⊕
. This system lies at a distance of
D
L
= 0.86 ± 0.05 kpc from Earth and the lens star has a mass of
M
L
= 0.234 ± 0.012
M
⊙
. We confirm that with a star–planet mass ratio of
q
= 0.57 × 10
−4
, OGLE-2017-BLG-1434 lies near the inflexion point of the planet–host mass-ratio power law.
The high-magnification microlensing event MACHO-97-BLG-28 was previously determined to be a binary system composed of either two M dwarfs or an M dwarf and a brown dwarf. We present a revised ...light-curve model using additional data from the Mt. Stromlo 74″ telescope, model estimates of stellar limb darkening, and fitting of the blend separately for each telescope and passband. We find a lensing system with a larger mass ratio, q = 0.28 0.01, and smaller projected separation, s = 0.61 0.01, than those presented in the original study. We revise the estimate of the lens-source relative proper motion to rel = 2.8 0.5 mas yr−1, which indicates that 16.07 yr after the event maximum the lens and source should have separated by 46 8 mas. We revise the radius of the source star using more recent reddening maps and angular diameter-color relations to R* = (10.3 1.9) R . K- and J-band adaptive optics images of the field taken at this epoch using the NIRC2 imager on the Keck telescope show that the source and lens are still blended, consistent with our light-curve model. With no statistically significant excess flux detection we constrain the mass, , and distance, DL = 7.0 1.0 kpc, of the lensing system. This supports the interpretation of this event as a stellar binary in the Galactic bulge. This lens mass gives a companion mass of , close to the boundary between being a star and a brown dwarf.
Background and Aims
Shiraz is the most widely planted winegrape cultivar in Australia. Sensory studies have indicated that different grapegrowing regions in Australia produce distinct styles of ...Shiraz wines that differ in flavour characteristics. The current project aimed to characterise the underlying volatile composition associated with regional Shiraz wine styles.
Methods and Results
Wines were selected from six geographically distinct regions and the volatile compounds were analysed using gas chromatography time‐of‐flight mass spectrometry to provide a comprehensive and holistic overview of the wine volatilome. A suite of R language based software enabled feature extraction and importance ranking, following an untargeted metabolomics approach. A classification model based on the random forests algorithm using the 80 most important compounds correctly associated all samples to regions. A range of these compounds, including terpenoids, benzenoids, esters, furan derivatives and aliphatic alcohols, has been associated with grape composition, winemaking influences and the ageing process.
Conclusions
The results suggest that the regional compositional differences in varietal wines may be influenced by all processes in the entire wine production chain.
Significance of the Study
The current study highlighted the chemical basis underlying the regional typicality of Australian Shiraz wines, and identified specific volatile compounds that may be associated with a region.
Background and Aims
Wines that exhibit regional characters are often the most sought after and the highest valued wines available in the marketplace. This study evaluated the sensory properties that ...were regionally distinctive for Australian Shiraz wines.
Methods and Results
Sets of wines (22–28 wines) from six prominent Australian Shiraz‐producing regions were initially evaluated by groups of local winemakers using a rapid sensory method called Pivot Profile (PP) to obtain maps of their sensory characteristics. Three or four wines from each region were then selected using cluster analysis of the PP data and were evaluated using sensory descriptive analysis. The regional PP assessments provided a sensory fingerprint of the variability of each of the regions studied and identified sensory characteristics that typified the largest groups of wines of each region. The descriptive analysis highlighted sensory characteristics that distinguished the wines from the different regions, including mint, cooked vegetal, viscosity, dark fruit and savoury attributes.
Conclusions
This work has provided detailed quantitative data on the sensory properties associated with each of the regions and demonstrated that there are distinctive, region‐specific sensory characteristics.
Significance of the Study
Sensory fingerprints that differentiate one region from another will aid producers and the trade in appreciating what can be expected from different regions; they allow targeting of production decisions to enhance distinctive sensory attributes and will assist in improved communication between marketers and consumers.
We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w = P/(pc super(2)). We present a ...method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4 m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z approximately 0.5 plus or minus 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in nearly real time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their apparent brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4 m telescope's natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 Type Ia supernovae, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for all of the Type Ia supernovae found by ESSENCE and used in our measurement of w, presented in a companion paper by Wood-Vasey and coworkers.
ABSTRACT
We report on the results of a simulation-based study of colliding magnetized plasma flows. Our set-up mimics pulsed power laboratory astrophysical experiments but, with an appropriate frame ...change, is relevant to astrophysical jets with internal velocity variations. We track the evolution of the interaction region where the two flows collide. Cooling via radiative losses is included in the calculation. We systematically vary plasma beta (βm) in the flows, the strength of the cooling (Λ0), and the exponent (α) of temperature dependence of the cooling function. We find that for strong magnetic fields a counter-propagating jet called a ‘spine’ is driven by pressure from shocked toroidal fields. The spines eventually become unstable and break apart. We demonstrate how formation and evolution of the spines depend on initial flow parameters and provide a simple analytical model that captures the basic features of the flow.
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