179 research outputs found
An algorithm for correcting CoRoT raw light curves
We introduce the CoRoT detrend algorithm (CDA) for detrending CoRoT stellar
light curves. The algorithm CDA has the capability to remove random jumps and
systematic trends encountered in typical CoRoT data in a fully automatic
fashion. Since enormous jumps in flux can destroy the information content of a
light curve, such an algorithm is essential. From a study of 1030 light curves
in the CoRoT IRa01 field, we developed three simple assumptions which upon CDA
is based. We describe the algorithm analytically and provide some examples of
how it works. We demonstrate the functionality of the algorithm in the cases of
CoRoT0102702789, CoRoT0102874481, CoRoT0102741994, and CoRoT0102729260. Using
CDA in the specific case of CoRoT0102729260, we detect a candidate exoplanet
around the host star of spectral type G5, which remains undetected in the raw
light curve, and estimate the planetary parameters to be Rp=6.27Re and P=1.6986
days.Comment: 8 pages, 13 figure
A highly contiguous genome assembly of the bat hawkmoth Hyles vespertilio (Lepidoptera: Sphingidae)
Adapted to different ecological niches, moth species belonging to the Hyles genus exhibit a spectacular diversity of larval color patterns. These species diverged ∼7.5 million years ago, making this rather young genus an interesting system to study a wide range of questions including the process of speciation, ecological adaptation, and adaptive radiation
Lattice Boltzmann simulations of lamellar and droplet phases
Lattice Boltzmann simulations are used to investigate spinodal decomposition
in a two-dimensional binary fluid with equilibrium lamellar and droplet phases.
We emphasise the importance of hydrodynamic flow to the phase separation
kinetics. For mixtures slightly asymmetric in composition the fluid phase
separates into bulk and lamellar phases with the lamellae forming distinctive
spiral structures to minimise their elastic energy.Comment: 19 pages, 5 figure
Linking satellite derived LAI patterns with subsoil heterogeneity using large-scale ground-based electromagnetic induction measurements
Patterns in crop development and yield are often directly related to lateral and vertical changes in soil texture
causing changes in available water and resource supply for plant growth, especially under dry conditions. Relict
geomorphologic features, such as old river channels covered by shallow sediments can challenge assumptions of
uniformity in precision agriculture, subsurface hydrology, and crop modeling. Hence a better detection of these
subsurface structures is of great interest. In this study, the origins of narrow and undulating leaf area index
(LAI) patterns showing better crop performance in large scale multi-temporal satellite imagery were for the
first time interpreted by proximal soil sensor data. A multi-receiver electromagnetic induction (EMI) sensor measuring
soil apparent electrical conductivity (ECa) for six depths of exploration (DOE) ranging from 0–0.25 to
0–1.9 m was used as reconnaissance soil survey tool in combination with selected electrical resistivity tomography
(ERT) transects, and ground truth texture data to investigate lateral and vertical changes of soil properties at
ten arable fields. The moderate to excellent spatial consistency (R2 0.19–0.82) of ECa patterns and LAI crop marks that indicate a higher water storage capacity as well as the increased correlations between large-offset ECa data
and the subsoil clay content and soil profile depth, implies that along this buried paleo-river structure the subsoil is mainly responsible for better crop development in drought periods. Furthermore, observed stagnant water in
the subsoil indicates that this paleo-river structure still plays an important role in subsurface hydrology. These
insights should be considered and implemented in local hydrological as well as crop models
Revisiting the transits of CoRoT-7b at a lower activity level
CoRoT-7b, the first super-Earth with measured radius discovered, has opened
the new field of rocky exoplanets characterisation. To better understand this
interesting system, new observations were taken with the CoRoT satellite.
During this run 90 new transits were obtained in the imagette mode. These were
analysed together with the previous 151 transits obtained in the discovery run
and HARPS radial velocity observations to derive accurate system parameters. A
difference is found in the posterior probability distribution of the transit
parameters between the previous CoRoT run (LRa01) and the new run (LRa06). We
propose this is due to an extra noise component in the previous CoRoT run
suspected to be transit spot occultation events. These lead to the mean transit
shape becoming V-shaped. We show that the extra noise component is dominant at
low stellar flux levels and reject these transits in the final analysis. We
obtained a planetary radius, , in agreement
with previous estimates. Combining the planetary radius with the new mass
estimates results in a planetary density of
which is consistent with a rocky composition. The CoRoT-7 system remains an
excellent test bed for the effects of activity in the derivation of planetary
parameters in the shallow transit regime.Comment: 13 pages, 13 figures, accepted to A&
Polarimetric Properties of Flux-Ropes and Sheared Arcades in Coronal Prominence Cavities
The coronal magnetic field is the primary driver of solar dynamic events.
Linear and circular polarization signals of certain infrared coronal emission
lines contain information about the magnetic field, and to access this
information, either a forward or an inversion method must be used. We study
three coronal magnetic configurations that are applicable to polar-crown
filament cavities by doing forward calculations to produce synthetic
polarization data. We analyze these forward data to determine the
distinguishing characteristics of each model. We conclude that it is possible
to distinguish between cylindrical flux ropes, spheromak flux ropes, and
sheared arcades using coronal polarization measurements. If one of these models
is found to be consistent with observational measurements, it will mean
positive identification of the magnetic morphology that surrounds certain
quiescent filaments, which will lead to a greater understanding of how they
form and why they erupt.Comment: 22 pages, 8 figures, Solar Physics topical issue: Coronal Magnetis
The future of planetary atmospheric, surface, and interior science using radio and laser links
Studies of planetary systems using spacecraft radio links constitute the field of Radio Science (RS). Experiments have been conducted on almost every planetary mission in the past five decades and have led to numerous discoveries. With substantial technical advancements in recent years, the following significant accomplishments are noted: • Elucidated the thermal history of the Moon from the GRAIL high precision gravitational field • Unveiled the interiors of Titan, Enceladus, Mercury, Phobos, Vesta, Ceres, and cometary nuclei from gravity fields, contributing to understanding their origins (Figure 1) • Sounded Titan, Saturn, and Pluto's atmospheres • Explored the surface properties of Pluto and 67P/Churyumov-Gerasimenko • Refined models for the atmospheres, surfaces, and interior structure of Mars and Venus • Juno and Cassini are currently measuring the gravity fields of Jupiter and Saturn to reveal their interior structures • Provided evidence for subsurface oceans on icy moons to expand understanding of potentially habitable bodies • Investigated the solar corona and the interaction of the solar wind with planetary atmospheres, and • Profiled the structure of Saturn's rings, which interact with moonlets
A Helicity-Based Method to Infer the CME Magnetic Field Magnitude in Sun and Geospace: Generalization and Extension to Sun-Like and M-Dwarf Stars and Implications for Exoplanet Habitability
Patsourakos et al. (Astrophys. J. 817, 14, 2016) and Patsourakos and
Georgoulis (Astron. Astrophys. 595, A121, 2016) introduced a method to infer
the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the
solar corona and farther away in the interplanetary medium. The method, based
on the conservation principle of magnetic helicity, uses the relative magnetic
helicity of the solar source region as input estimates, along with the radius
and length of the corresponding CME flux rope. The method was initially applied
to cylindrical force-free flux ropes, with encouraging results. We hereby
extend our framework along two distinct lines. First, we generalize our
formalism to several possible flux-rope configurations (linear and nonlinear
force-free, non-force-free, spheromak, and torus) to investigate the dependence
of the resulting CME axial magnetic field on input parameters and the employed
flux-rope configuration. Second, we generalize our framework to both Sun-like
and active M-dwarf stars hosting superflares. In a qualitative sense, we find
that Earth may not experience severe atmosphere-eroding magnetospheric
compression even for eruptive solar superflares with energies ~ 10^4 times
higher than those of the largest Geostationary Operational Environmental
Satellite (GOES) X-class flares currently observed. In addition, the two
recently discovered exoplanets with the highest Earth-similarity index, Kepler
438b and Proxima b, seem to lie in the prohibitive zone of atmospheric erosion
due to interplanetary CMEs (ICMEs), except when they possess planetary magnetic
fields that are much higher than that of Earth.Comment: http://adsabs.harvard.edu/abs/2017SoPh..292...89
Transiting exoplanets from the CoRoT space mission I - CoRoT-Exo-1b: a low-density short-period planet around a G0V star
Context. The pioneer space mission for photometric planet searches, CoRoT,
steadily monitors about 12,000 stars in each of its fields of view; it is able
to detect transit candidates early in the processing of the data and before the
end of a run. Aims. We report the detection of the first planet discovered by
CoRoT and characterizing it with the help of follow-up observations. Methods.
Raw data were filtered from outliers and residuals at the orbital period of the
satellite. The orbital parameters and the radius of the planet were estimated
by best fitting the phase folded light curve with 34 successive transits.
Doppler measurements with the SOPHIE spectrograph permitted us to secure the
detection and to estimate the planet mass. Results. The accuracy of the data is
very high with a dispersion in the 2.17 min binned phase-folded light curve
that does not exceed 3.10-4 in flux unit. The planet orbits a mildly metal-poor
G0V star of magnitude V=13.6 in 1.5 days. The estimated mass and radius of the
star are 0.95+-0.15Msun and 1.11+-0.05Rsun. We find the planet has a radius of
1.49+-0.08Rjup, a mass of 1.03+-0.12Mjup, and a particularly low mean density
of 0.38 +-0.05g cm-3.Comment: A&A letters (in press) - 4 pages - 3 figure
Maladaptive behaviors are linked with inefficient sleep in individuals with developmental disabilities
The purpose of the current study was to assess the relations between nightly sleep patterns and the frequency of daily maladaptive behavior. Antecedent and consequential relations between sleep patterns and behavior were evaluated with time series analysis. Sleep efficiency and maladaptive behavior were determined for 20 female residents of an institutional care facility for adults with developmental disabilities. Daily maladaptive behavioral data and nightly sleep/awake logs were collected for 4 months for each participant. Efficient sleep patterns were significantly associated with lower frequencies of maladaptive behaviors. All lagged cross-correlations 8 days before and 8 days after an evening of sleep were significant. These findings suggested that inefficient sleep was associated with increased maladaptive behaviors and that the lagged associations reflected a chronic but not an acute linkage between sleep and behavior
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